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5
Indice degli interventi
08
The Enrico Fermi School: Tradition and perspectives
G-F. Bassani
10
The audacious beginnings and the first developments of the Enrico Fermi School in Varenna
in physics and education
G. Salvini
16
Varenna: Highlights on the history of physics
R.A. Ricci
25
The Varenna School and particle physics
N. Cabibbo
31
Presentation of the Course ``Research on Physics Education''
E.F. Redish
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ALLOCUZIONE TENUTA DAL PRESIDENTE DELLA SOCIETAÁ ITALIANA DI FISICA
IL 15 LUGLIO 2003 PER LA CELEBRAZIONE DEL 50ë ANNIVERSARIO
DELLA SCUOLA "ENRICO FERMI" DI VARENNA.
Signor Sindaco, Signor Presidente della Provincia di Lecco, AutoritaÁ Presenti, gentili Signore e
Signori,
nel celebrare il 50ë anniversario della Scuola "Enrico Fermi" di Varenna desidero anzitutto ringraziare
tutti i presenti per la loro partecipazione, in particolare il Sindaco Cavalier Pier Antonio Cavalli, il
Presidente della Provincia di Lecco Avvocato Mario Anghileri, il Presidente e il Direttore dell'Istituzione Villa Monastero Marco Bandini e Roberto Panzeri, il Professor Vladimir Kouzminov dell'UNESCO, il Dottor Mario Negri in rappresentanza della Cariplo, Giovanni Ricco in rappresentanza dell'INFN,
Giorgio Benedek dell'INFM, il Presidente dell'Istituto Lombardo di Scienze e Lettere Emilio Gatti,
docenti e allievi del corso "Research in Physics Education" che oggi ha inizio. Abbiamo ricevuto
telegrammi dal Direttore Generale del MIUR Silvio Crisciuoli, dal Presidente dell'Accademia dei Lincei
Edoardo Vesentini, dal Direttore Generale del CERN Luciano Maiani, dal Prof. Carlo Salvetti, dal Prof.
Carlo Rubbia, dal Prof. Giampietro Puppi e un telegramma dal Capo dello Stato Carlo Azeglio Ciampi
che desidero leggere:
"Il cinquantenario di una istituzione prestigiosa come la Scuola di Fisica "Enrico Fermi" a Varenna rappresenta una utile occasione di riflessione sullo stato della ricerca in Italia.
La Scuola di Varenna eÁ un esempio di eccellenza italiana nel panorama scientifico internazionale
con una storia illustre illuminata dall'apporto e dalla guida di nomi di scienziati straordinari e
Premi Nobel.
Le scienze fisiche in Italia vantano una gloriosa tradizione di studi e successi. Da questa dobbiamo trarre il coraggio e l'entusiasmo per guardare con fiducia all'avvenire della nostra scienza
nello spazio europeo della ricerca scientifica e della formazione.
Occorre sostenere e incentivare gli istituti di alta cultura in grado di produrre e formare giovani
talenti, nuovi scienziati. EÁ questo l'investimento essenziale per il futuro dell'Italia e per la sua
presenza competitiva in Europa e nel mondo.
Con questa consapevolezza e sentimenti di vivo apprezzamento rivolgo alla SocietaÁ Italiana di
Fisica, alla Scuola "Enrico Fermi" e a tutti i partecipanti il mio piuÁ cordiale saluto ed augurio."
Firmato Carlo Azeglio Ciampi.
G.F. Bassani
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THE ENRICO FERMI SCHOOL: TRADITION
AND PERSPECTIVES
G.F. Bassani
Scuola Normale Superiore
Piazza Cavalieri, 7 - Pisa
8
We are here convened to celebrate the Jubilee of
the ``Enrico Fermi'' School of Varenna, whose
first course was held in 1953. The Italian Physical Society looks back with pride to the role of
this School in educating young physicists on
specific subjects, and in reporting the main accomplishements made in the various fields. We
look back to past achievements and formulate
hopeful perspectives for the future.
The birth of the School is due to the wisdom of
the President of the Italian Physical Society of
that time, Giovanni Polvani, who had the example of the Les Houche School, founded by the
French Physical Community one year earlier in
1952. He was so proud of this achievement to
mention it in his will, and to choose as his
resting place the Varenna Cemetery. To him a
street in Varenna has been dedicated by the
administration led by the former Mayor Dr.
Giorgio Monico, whom I wish to thank. Professor Polvani used to open all the courses with
speaches in beautiful literary Italian, and I recall
that he looked somewhat disappointed when the
translation of his sentences was so poor and
took a much shorter time than the original.
The occasions to meet with the prominent
people in a particular field from all countries
and with those who would become famous in
the future were not yet available in the fifties.
The consequences of the war were still felt, and
it was not easy to preserve the international
character of research, which was one of the
great traditions of physics, even during the
years of the nationalistic madness. The Varenna
School produced such an opportunity, and the
School developed its own character, which has
been preserved from the beginning through the
subsequent years and decades.
First of all its international vocation, without
any exclusion for political reasons. This was the
place where also physicists from Russia and
Easter European Countries were present without any concern, even in the coldest years of the
cold war. Then the very friendly atmosphere and
the costant exchange of ideas between lecturers, seminar speakers, observers and students. This was and still is encouraged by the
living together in a beautiful place, in the same
hotels and restaurants, and I wish to thank the
Directors of the Hotel Victoria Mr. Severino Beri
and of Olivedo, Mrs. Antonietta Colombo, for
their kind collaboration through many years,
and particularly Mrs. Seta Vitali who preserved a
handwritten booklet, with sentences signed by
the most distinguished guests. This booklet is
now in possession of the Italian Physical Society
as an important document. A sincere thank is
also due to Dr. Giorgio Monico, Mayor of Varenna for many years and a standing friend of the
Italian Physical Society. For the interaction between students and teachers the habit of correcting and distributing the manuscripts of the
lectures here, during the time of the School, has
been also helpful. The pleasent atmosphere is
also encouraged by social events, now somewhat reduced, but greatly emphasized in the
early years of the School. They included for
each Course two organized trips and one fabulous social dinner. A special recognition for
their contributions during all these 50 years is
due to Gioacchino GermanaÁ the secretary of the
SIF in the sixties, to the subsequent secretaries
Gerda Wolzak, and Enrica Mazzi, whose example is being now so well followed by Barbara
Alzani.
For many reasons, and particularly for the
new acquaintances and friendships, the Varenna
School was for many of us an unforgettable experience in our professional life. Recently, when
calling a few friends and colleagues to solicit
interest and support for the continuation of the
School, I was reminded by many of them that we
first met in Varenna.
In the early years the duration of the courses
was of three or four weeks since the subjects
were rather general, and only one course was
held every year. The first course of 1953 was on
elementary particles, directed by Giampietro
Puppi, and so was the course of 1954 with the
participation of Enrico Fermi. The course of
1955 was on nuclear physics, and was directed
by Carlo Salvetti. He has not been able to come,
but he sent me a letter recalling that at the end of
that course all the teachers rushed to Gineva to
take part in the first international conference of
the peaceful use of nuclear energy so that the
two events are somewhat connected in the
minds of the protagonists. The course of 1956,
directed by Luigi Giulotto, was on ``ProprietaÁ
magnetiche della materia''.
Other courses followed in the subsequent
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years. I recall the first course I attended as a
student in 1957. It dealt wih solid state physics
and was directed by Fausto Fumi, with the
participation of the most important figures in
the field, such as Fred Seitz, Jacques Friedel,
Walter Kohn and Sir Nevill Mott. Of that course I
recall in particular the first presentation of the
B.C.S. theory of superconductivity by Robert
Schrieffer.
All the courses and speakers are listed in the
blue booklet which is updated every year, and is
now in your possession. Looking through it, one
gets the feeling of a glance through the physics
of the last fifty years. In the beginning, the lectures of each course were published in ``Supplemento al Nuovo Cimento''. Since 1963 each
course is published as a carefully edited book,
and some of these volumes have become classics in their respective fields.
As said, the duration of the early courses
was of three or four weeks, and the format
always consisted of a relevant number of lectures intended to give a general background
and others to present the latest achievements.
More recently it was recognized that a twoweek duration, maintaining the same format,
was more ideal and appropriate, also because
more specific subjects are chosen for each
course. With the shorter duration we could
have more courses every year, in general two
or three courses, up to four courses in the past
two years. Three courses are planned for next
year.
The following speakers will talk about the
early times of the ``Enrico Fermi'' School, about
the more recent courses, and will describe, as an
exempification, the development of the specific
field of high-energy physics seen through the
courses of the ``Enrico Fermi'' School.
I wish to close by posing questions which
come to one's mind every time one celebrates a
Jubilee. What are the perspectives for the future? Will the School continue in its present
format? Are changes needed? I am sincerely
convinced that the ``Enrico Fermi'' Varenna
School has a great future and that its present
format is still appropriate. Probably the School
will continue as long as Physics remains the
basic science of the natural world. The traditional fields will continue to develop, and also
in the future it is likely that the predictions that
a given field is totally exhausted will be proven
9
Foto di gruppo dei relatori. Da sinistra N. Cabibbo, G. Salvini, G. F. Bassani, E. F. Redish e R. A. Ricci.
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fallacious. Suffice it to recall for the past lasers
developments in spectroscopy when spectroscopy seemed a closed field, in atomic physics
the novelties with atom manipulations, in
semiconductors the novelties with nanostructured materials and so on. In addition, a variety
of new subjects will develop because of the
great impact that many aspects of physics have
on industry and on the society. This year we
have had for the first time a course on Archaeometry directed by Mario Piacentini, Marco Martini and Mario Milazzo. A course on
Complex Systems, directed by Francesco Mallamace and Eugene H. Stanley, with more than
one hundred participants has just concluded. A
course on Physics Education Research is
starting today under the direction of Matilde
Vicentini and Edward Redish and next there
will be a course on Fermi Liquids. The proposals for future courses are numerous and highly
motivated. The future of the School is not in
jeopardy from this point of view, however the
present situation requires increasing the international coordination. For this reason, last
April we had a meeting in Paris to verify the
absence of relevant overlap between the courses planned at the Les Houche School, at the
Varenna School and at the Bad Honnef School.
A course in metrology is planned alternatively
every three years in France and in Varenna. Our
purpose is to continue such a coordination in
the framework of the European Physical Society, in order to have jointly the sponsorship of
the European Commission. This will assure
good teaching and good opportunities also for
the future generations.
THE AUDACIOUS BEGINNINGS AND THE
FIRST DEVELOPMENTS OF THE ENRICO
FERMI SCHOOL IN VARENNA IN PHYSICS
AND IN EDUCATION.
G. Salvini
Dipartimento di Fisica
UniversitaÁ ``La Sapienza'', Roma
I shall recall the beginning of this school in
1953±54, and what we learnt and what we did
not yet know in those years. After this, I shall
briefly comment on the decisive years 1955±63
at Villa Monastero, which established the basis
of our present knowledge in physics, in con-
densed matter and in elementary particles. I
shall recall how the exchange of ideas and
mathematics from cold superconductors to high
energy research (from Cooper pairs to heavy
Higgs) have given us a new larger view of our
Universe, and has established an irreversible
unity between solid state, astrophysics, elementary particles.
When going to education and to physics,
which is the aim of this Summer School, we can
recall the unity of science, the fact that we must
work together to conquer facts and new ideas
we do not know yet, with a humble respectful
attitude toward our universe which we are still
far from understanding. We must explain to
students of all ages (and to ourselves too) our
respect for both the subtle progress of our
knowledge in the preparation of instruments
and experimental measurements, in observation
on the Earth and on the sky, and our clear still
incomplete progress in theory and mathematics.
At the end, we underline the importance of
Summer schools when analyzing specific recent
details, defining general programs in physics
research, enlarging the participation in research
to all humans, independently of their race and
their country.
1. ± Introduction
I am very grateful for this occasion to talk to
you to day, and to comment the beginnings and
the consequences of the Enrico Fermi School.
For more than fifty years I have been a lover of
cosmic rays and elementary particle physics
and, at least in some physicists' views, I have
been what we call to day a ``reductionist''.
I have seen and in part I have contributed to
the birth of new machines (the betatrons, and
later the Synchrotrons) prepared for research,
and for creating new particles of masses 300,
1000, 2000, 20 000, 200 000 times the mass of the
electron, and in a few cases I had the opportunity to directly follow their discovery ( J= ; W;
Z). They were hectic years, with great attention
to the facts, in an intense race to arrive first (1).
One could say that the aim was to understand
the properties of each elementary particle:
mass, charge, angular momentum, coupling
constant, symmetry and symmetry violation,
and their interactions.
During this hunting, many of us, certainly I for
many years, have arrived at this nice 2003, with
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the ingenuous or candid hope of having identified the main bricks of our Universe. This may
recall to some of us who like history and analogies, the search, 800 years ago of the Holy
Graal, as described by Wolfram Von Eschenbach (1170±1220) (2). In fact the Higgs
seems to be today the particle (or the particles),
which could have the honour of closing the
search successfully, for being on top of that
general theory which is known as the Standard
Model. I shall give some details on this in the
next paragraph. These were years of great satisfaction to the elementary particle physicists.
The feeling was that our knowledge of the Universe was ``converging'' to a definitive representation, and we could go home and rest,
having earned the ``warrior' s rest''.
But reality soon appeared rather different.
Just in these years, with this new fascinating
millennium, new facts and knowledge emerged,
which have every right to blow down our house
of cards and to postpone our hopes for a final
synthesis.
I shall dedicate my talk to this reality, and to
its consequences when teaching physics to the
coming generation. To do this, I shall start now
from the beginning, the history of the first years
of the Varenna School.
2. ± The opening at Varenna, the first two
years in 1953-54.
Let me start with the words of Giovanni Polvani at the inauguration of the school, in 1953 (3)
He asked himself: ``Next year, and in the following years, shall this International School of
physics, open again, with new courses of physics?'' I personally think that both the new President and the Council of SIF will consider the
repetition, notwithstanding the difficulties of
the organization. But there is something more,
and I put the question to myself: Why limit this
activity to Physics? Why not form an Enterprise,
a Foundation Ð I do not know Ð which may
assume the responsability of organizing every
year in this Villa some international high level
studies regarding science, history, art? The
place is beautiful, perhaps the best along this
lake, the climate is good, international relations
are easy....''
And now let me recall the words of Gianni
Puppi, when commenting the first thirty years of
this Varenna school, in 1983 (4):
``The first year of the school (1953) was centered on the techniques to detect elementary
particles, on the origin of cosmic rays, and with a
first glance at pion physics, which became the
main argument of the following year. The second
year, 1954, (which was again with Gianni Puppi
as the Director, ndr) was a memorable event, not
that the first year was not very interesting too,
but for a series of ``Planetary Conjunctions'',which did create around this second course a
particular ``charisma'', considering also that just
in that period we would arrive at a kind of
``summa theologica'' about what we knew of pion
physics, which was for a rather long time a basic
reference. But the death of Enrico Fermi reverberated a particular light, and when we talk of
the Varenna School, this second year and Enrico
Fermi come to our minds. But this second year
was rich also for other pysicists, like Rossi,
Bernardini, Heisenberg, who had a fundamental
role with extraordinary lectures. In this second
year we put together the men who were preparing new accelerating machines, English, French,
Italians.......''
I was present, and I was guided by my friend
and Director Gianni Puppi (5). Let me remember
two suggestions by Enrico Fermi in the last
months of his life. He was powerful in ideas and
encouragement to all persons around him. One is
his suggestion to increase the injector energy of
our synchrotron for electrons, to improve its luminosity, after having heard the presentation of
Enrico Persico and myself. The other, to Gilberto
Bernardini and Marcello Conversi, to devote part
of the available funds to build a powerful electronic computer in Italy. Both suggestions had
immediate great consequences for the progress
of Italian Physics (6). As we know, Enrico Fermi
had to return to the States in September, where
he died on November 28, 1954 (7).
3. ± Those magic ten years, toward the unity
of physical sciences.
I must recall that some general consequences
descended to the Physics of the World, from that
1954. In fact the ten years that followed 1954
opened new ideas and strengthened to new
levels, experimental, theoretical, epistemological even, the relations between the physics of
condensed matter and elementary particles. The
Varenna School was always very timely in announcing, commenting, studying this evolution.
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12
I shall limit myself to recalling one case only,
which perhaps inspired all physics in these last
decades. I mean that line of thought which in
general goes under the name of ``Spontaneous
Symmetry Breaking''. Let us start from its origin.
The physics of the first half of the last century
had an unresolved problem of great interest: the
explanation of superconductivity. It is that
phenomenon by which many substances when
cooled down to a very very low temperature
lose their ohmic resistence, and may support
very heavy electric currents without getting
warm. It is a real current, which allows for instance the preparation of magnets of high fields
(ten tesla and more) which are necessary to
contain in the donut of a synchrotron the protons, while being accelerated to reach a high
kinetic energy. Superconductivity was an experimental discovery, due to Kamerlingh Omnes
in 1911. At first it appeared an incredible phenomenon, a challenge to the best physicists in
quantum mechanics and mathematics (8).
Well, this problem has been resolved in 1956±
57 by three theoretical physicists who rightly
earned the Nobel Prize for it: J. Bardeen, L. N.
Cooper, J. R. Schrieffer (9). This result was immediately discussed, at the Varenna School of
1957, July 14±August 3, directed by F. Fumi,
with the lecture presented by R. Schrieffer, one
of the three authors (10).
But this is only the beginning of a beautiful
story, which induces us to meditate on the unity
of physical sciences. In fact, the explanation of
superconductivity was based on the discovery
that electrons inside the solid structure of matter
can join in pairs at various distances, and even
with material in between. These are the Cooper
pairs,which when formed behave like bosons (11),
not as single electrons of spin . In this condition
the electrons flow in matter and achieve that incredible conductivity with zero resistence. I
know I am oversimplifying the problem.
But there is even more, in this discovery. This
idea of associating the electrons,which are fermions, in pairs, opened new views in other fields
of quantum mechanics, beyond the structure of
electrons in condensed matter. Some physicists
asked themselves if these new Cooper ideas could
be used to explain a problem which was, as Pais
said, a stumbling block (12) for the development of
elementary particles: the difficulty to describe
with coherent equations and without lethal divergences to infinity the particles with a mass
different from zero, like hadrons and leptons.
Something like considering the mass of a particle
as the gap in energy observed in superconductivity. The first inspiration in this direction
came actually from G. Jona-Lasinio and Y. Nambu,
starting with the results on superconductivity (13).
It has been a great march ahead which I cannot
recall here. Let me only say that this symbiosis
between so different branches of physics has
produced in a few years enormous progress in
the field of elementary particles. A new intelligence started to explain particles and their
masses. The way was to admit the existence of a
scalar field which can generate the masses of the
elementary particles (14). This field has a particle
which from its proposer took the name of Higgs
particle, as I mentioned in my introduction (15).
This Higgs mechanism has given charge and
mass to all existing particles, with legitimate
mathematical respect. The verification that this
is the right way to explain the hadronic and
leptonic structures is in its numerous verifications. It seems impossible that we are not on the
right path. But we must say, as you know, that
this Higgs, this ``Queen Bee'', has not been
identified yet (16).
4. ± The School of Varenna in those ten years
1954-1964.
What I said is only an example of the march
onwards of all physics in those years, with reciprocal inspirations. Let me recall only something of its story.
± The discovery of neutrinos and their properties (1958±1959) by B. Touscek, L.A. Radicati,
A. Wheeler (17).
± The Physics of Plasma, 1959 (18).
± Topics on Radiofrequency Spectroscopy (19).
± Evidence for gravitational theories (20). Gravitational waves (21).
± The development of symmetry and symmetry
breaking up to the Cabibbo angle and the CKM
matrix (22).
± The illustration of the great topics in elementary particle physics (23), directed by Conversi,
1962.
± The high energy neutrino physics, T.D Lee, 1527 June, 1964 (24);
± The course on liquid helium directed by G.
Careri (1961) (25).
I was present, and not as a protagonist. I dare
to say that those footpaths along the edges of
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the Lake in the beautiful garden of Villa Monastero, so inviting to meditation, have some responsability for the development of physics in
those ten years.
5. ± Some still unresolved, important problems of physics.
Other friends will recall the developments of
the Varenna School from the sixties to the present years, the last being in 2002, on neutrino
physics, stars and nuclei. I only wish to report
today some facts, which arrived to shake some
of our certainties. They may remind us about
what we know and what we do not know yet in
physics, and from this we may try to deduce
some consequences in our programs to physics
education.
± Dark Matter. Not only protons, neutrons,
electrons, photons, neutrinos, exist and are
rather stable in our Universe. Analysis of the
galaxies indicate that there is more mass than
we thought, and it may be that this mass which
does not emit light (we call it dark matter) is
due to new particles outside those predicted
in the Standard Model (supersymmetric particles) of unknown mass and charge and stability (26). Part of the dark matter could even
be some new form of material or energy condensation, which goes beyond our present
representation of matter.
± We have not yet succeeded in giving a coherent and complete picture of the fields and
forces which rule our Universe: gravitational,
hadronic, electroweak. We aspire to a synthesis, and some of our best theoreticians work
towards it. The more famous example in these
years is the subtle fascinating ``string theory'',
which requires new dimensions and forms
with respect to the old quantum model of
elementary particles, with a new representation of elementary matter, larger than any old
``reductionism''. We are still rather far from
definite success (27).
± Our Universe, as observed by us through our
best and powerful instruments from the Earth
and from satellites is sending unexpected
signals (for instance the gamma ray bursts)
and great condensations of energy (black
holes). The extension and destiny of our Universe, collapse, expansion, endless continuity,
cannot be foreseen with our present poor
evidence (28).
When keeping this in mind, it appears rather
strange or ridiculous to pretend to know at
which level our knowledge of the Universe will
be within three hundred years from now, the
time distance between us and Isaac Newton.
Our difficulty to foresee the future is tantalizing
and keeps every field of physics in continuous
evolution, and unforeseeable.This is one reason
why research in physics is cultivated by humans
with unquenchable ardour, and with a capacity
of altruism and collaboration. Without these
qualities progress would be impossible, and I
dare to say that this collaboration is the best
plus sign of our humanity.
6. ± Education in Physics: A new perspective?
Many things in education are obvious and
known: To teach everyone to look with free eyes
at experimental facts, not to believe any authority uncritically. I think all unbiased scientists believe this. But on the basis of the new
developments in physics I just recalled, I think
we can now add something more.
It is time, perhaps, to cancel, if we ever had it,
the assumption that our understandig of the
elementary structure of our Universe, is close to
any final conclusion. New experimental facts
shall follow. The Higgs and other new particles
are a great progress of today. But it is important
to recognize that this Higgs may be only a lucky
incomplete solution of our present understanding. We must expect for our descendents a
larger and larger view, perhaps as large as it is
now with respect to Newton's time. This produces the feeling that we are still at the beginning of scientific knowledge, and there is a long
way to go ahead of us. This feeling makes me
happy.
We may also observe something more in our
research in physics: the basic ideas of our science migrate successfully from one field to the
other (remember my example with spontaneously broken symmetry, a fundamental idea
which came from condensed matter to elementary particles), and there is no hierarchy among
the different branches of physics: I dare to say
that it is important in education to give young
people (I imagine I am talking to middle school
teenagers, now entering university) the solid
evidence of this open progress.
This can also be made clear when we stick to
experimental facts: the students themselves can
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verify how fast our progress is going, from little
things, like the continuous progress in telephones, Internet, computers, to the great news,
from astrophysics, laboratories of biology, physics etc. This huge growing development of science and technology, shall give to good teachers
the possibility to show that full knowledge of the
world in which we live is still far from us, and it is
something that we may conquer step by step,
observing nature and making new experiments.
And what we learn is well beyond our possible
imagination: think of the origin of the Planck
constant; of the laws of quantum mechanics; of
the gravitational theory inspired to Newton and
others by the motion of the Moon, and the periodic movement of satellites around Jupiter.
Conquests like these are evidence of the cross
fertilization between different branches of physics, something which maintains our joy in physics and the interest to teach it.
7. ± Forgive me for a three minute digression
to botany.
14
I must confess that this thinking of the reciprocal help between different branches of
knowledge has suggested an image to me, which
is probably no more than a witticism, which I
hope you will forgive me.
In these days, while talking with friends who
are experts in botany, I learnt more about an
extraordinary plant, the Ficus Magnolioides (or
Macrophylla), see fig. 1 and 2 (29). It is not the
only one of its genus. It belongs to the family of
Moracee, like the Mulberry tree. These extraordinary plants increase the power of their
trunk or even multiply it, with embryonic gems
which originate even from the highest branches
of the tree. These elementary roots emerge
subtle and pendulous and descend toward the
ground. When touching the ground, they suck
water and nourishment, and will grow and get
stronger, so that at the end they form a new
trunk which may weld with the father trunk, or
remain as a brother tree. In some cases the Ficus Magnolioides with its offsprings can constitute a gentle amphitheater which may shelter
a group of men and animals.
With perhaps a too audacious analogy I
thought that such a tree may be a proper image
of our physics. What emerges unexpectedly
from the leafy branches of the ficus may definitely determine its development, and produce
Fig. 1.
new powerful lines of the trunk. Usually plants
do not receive such a help from the top (30).
Well, our history of physics, and especially in
these last years, reminds me of the Ficus Magnolioides. The tree enlarges and renews its
history, like our mind, and new elements, new
ideas from unexpected directions increase the
might of the plant during the centuries.
Fig. 2.
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8. ± The importance of summer schools.
All the history of good international summer
schools demonstrates that they have an irreplaceable role in the industry of culture. Published articles in qualified magazines, which
undergo rather severe judgement, usually have a
well-established target; books and treatises
have larger aims, but hardly can they discuss
last month's discoveries. The schools like Varenna may contain and express all ferments of
the last weeks, and may transmit the impetus
and even the anguish of physics in the moment
of its development. Young, new people meet,
and this is important. Collaboration gives our
work its human visage.
We discover how many important results and
discoveries have the mark of reciprocal help and
altruism. This is the benefit of travel and exchanges that scientists have always had along the
centuries. It was the master key for the fast development and spread of science. Summer
schools definitely help the problem. Their length,
5-15 days, is often enough for a first exchange.
Later you go home and work with new stamina,
even ready to change your angle of view for the
best.
But this is true also for any age. The grown-up
physicist is bound to his problem, has a difficulty
in changing. The summer school compels him to
look around, to compare his way of teaching with
the teaching art of others, to look directly or to
catch a glimpse of other sciences. We know that
sometimes a glimpse is enough to change our life.
A last point, which I consider important. We
give hospitality in our summer schools to students of any colour race origin, from countries
in course of development, that do not have yet
industries and universities comparable with
those in some countries in Europe, in the United
States, in Russia, in Japan.
Going through the Varenna School we had the
occasion to verify that the capacity to improve
original mathematics and opening new experimental activity, as well as poetry and musics, is
distributed with equal probability among the
humans of the Planet.
Of course, many of us know this since many
years. But in case some one is doubtful about
this equality, the summer international schools
are the best occasion to acknowledge to all hu-
mans of our Planet equal capacity and equal
rights to scientific culture.
I close my talk here. I tried to express to you
my pleasure in being here, my confidence in our
future, my joy for anything new that our great
grand children will discover and learn, and my
gratitude to all the persons who work so hard
for the success of this school.
Bibliografia
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
L. M AIANI, Enciclopedia delle Scienze Fisiche (ESF).
Enciclopedia Treccani: Particelle Elementari, Vol. IV
(1994) p. 467- 484; A. PAIS, Inward Bounds (Oxford University Press, 1986).
Lessico Universale Italiano, Enciclopedia Italiana. Vol.
XXIV (1970) p. 64.
G. POLVANI, Discorso inaugurale. Suppl. Nuovo Cimento,
Vol. XI, Ser. IX, No. 2 (1954).
G. PUPPI , Discorso di ricordo al 30 mo anniversario della
fondazione della scuola di Villa Monastero in Varenna,
1984 reported by R.A. Ricci, President of SocietaÁ Italiana
di Fisica.
E. PERSICO , G. S ALVINI . Suppl. Nuovo Cimento, Vol. II, Ser.
X, (1955) p. 442-459.
C. BERNARDINI and L. BONOLIS (Editors), Conoscere Fermi,
nel centenario della sua nascita, Articolo di G. Salvini, p. 1.
E. SEGREÁ : Enrico Fermi, fisico (Zanichelli, Bologna,
1987).
C. RIZZUTO, SuperconduttivitaÁin ESF, op. cit., Vol. VI, p. 2.
J. BARDEEN , L.N. C OOPER and J.R. S CHRIEFFER, Phys. Rev.
106 (1957) 162.
J.R. S CHRIEFFER, Theory of Superconductivity, Suppl.
Nuovo Cimento, Vol. VII, Ser. X, No. 2 (1958), 377.
ESF, op. cit., Vol. II, p. 236; Vol. II, p. 844.
A. PAIS, op. cit. in (1). In this volume the difficulties afforded in the early '60 are magistrally presented, and emphasis is put on the light shed on physics by condensed
matter. See, especially Sections 20, 21, pp. 500-620.
L. B ONOLIS e M.G. M ELCHIORRI (Editors), Vita di Gianni
Jona, in Fisici Italiani del tempo Presente (Editore
Marsilio, 2003) p. 173-213;
A. P AIS , op. cit. pp. 594-600.
P.W. HIGGS ; Phys. Rev. Lett. 12 (1964) 132.
A great experimental research has been done, and is still
active at CERN with LEP and at Fermi Lab, USA, with
Tevatron.
Curse XI, 1959, Directed by L. Radicati, 29 June-11 July
1959.
Directed by H. Alfven, 2-15 September 1959.
Course XVII, directed by A. Gozzini, 1-17 August 1960.
Course XX, 18 June-1 July, 1961.
J. W EBER , in the course of Moller: Methods for measurement of gravitational waves.
The development of symmetry and symmetry breaking
up to the Cabibbo Angle and the CKM matrix has been
discussed in many Varenna Schools.
Course XXVI, Selected topics in elementary particle
physics.
Course XXII, The high energy neutrino Physics 15-27
June, 1964.
Course XXI, 3-15 July 1961.
S. B ONOMETTO and J. PRIMACK , Dark Matter in the Universe, 25 July-4 August, 1995, Course CXXXII of Varenna
School.
See, D. Amati in ESF op. cit., Corde Relativistiche, Vol. I,
p. 765.
M. REES, Prima dell'Inizio (Raffaello Cortina Editore, 1998).
On Ficus Magnolioides you can look up in Enciclopedia
Agraria, p. 616, and Exotica, p. 1172.
I wish to express my gratitude to Professors Alessandro
Pignatti and Antonio Graniti of the Accademia Nazionale
dei Lincei, for their help in understanding the propertirs
of the Ficus Magnolioides.
15
IL NUOVO SAGGIATORE
VARENNA: HIGHLIGHTS IN THE HISTORY
OF PHYSICS
R.A. Ricci
INFN - Laboratori Nazionali di Legnaro
Viale dell'UniversitaÁ, 2 - 35020 Legnaro, Padova
1. ± Introduction
Twenty years ago, June 1983, a celebration
of the 30th anniversary of the foundation of
the ``International School of Physics'' (1953)
of the Italian Physical Society, was held,
under my chairmanship, as a President of SIF
at the time.
I introduced that celebration, here in Villa
Monastero, with these words:
16
``We are here today for two reasons: The
first concerns the celebration, in the way
which is usual for us without too many
ceremonies, the 30 th anniversary of the Varenna School. The meaning and the importance of such an event does not need to be
explained. The second reason is the ``normal''
inauguration of the Courses of this year
starting with the present one, directed by M.
Ghil on ``Turbulence and predictability in
geophysical fluid dynamics and climate dynamics''.
I think that we can repeat exactly the same
words, since the usual way to celebrate the
event is in our tradition and due to the fact that
the ambience and the audience are, together
with some of the Italian protagonists, those of a
normal physics course with a large participation
of young physicists.
It is also interesting to note that in both circumstance (1983 and 2003) the courses coincident with our celebrations are not related to
the more usual topics, like elementary particles,
nuclear and solid state physics, but to subjects
with a wide interdisciplinary spectrum. The
present course, directed by E. J. Redish and M.
Vicentini is in fact devoted to ``Research on
Physics Education''.
This shows how the history of the Varenna
school is embedded in the history of physics
covering almost all the aspects of the physical
science from the more fundamentals to those
strongly related to applications and information.
Fig. 1. ± The cover of the booklet devoted to the 30th
anniversary of the Varenna School (1983).
Coming back to the 1983 ceremony, which
was reported in a special book, whose cover is
reported in fig. 1, I have to mention that one of
the main aspects of that celebration was the
presence of some illustrious protagonists of
the unforgettable venture of the Varenna
School so strongly connected with the revival
and further development of physics in Italy,
after the second world war.
Figure 2 shows a picture of the opening of that
ceremony with some of them: Carlo Castagnoli,
Gilberto Bernardini, Antonio Rostagni, Giuliano
Toraldo di Francia, Giuseppe Occhialini.
Also present (not shown in the picture)
were Giampietro Puppi, the director of the
first two courses in 1953 and 1954 and Piero
Caldirola, while Edoardo Amaldi, Giorgio
Salvini and Carlo Salvetti were not able to
come but were of course with us in a friendly
recollection.
IL NOSTRO MONDO
Fig. 2. ± Opening ceremony of the 30th anniversary of the Varenna School at Villa Monastero (1983). From right to
the left: C. Castagnoli, C. Bernardini, R.A. Ricci, A. Rostagni, G. Toraldo di Francia, G. Occhialini and the major of
Varenna, G. Monico.
2. ± The beginning
Already at the beginning, the Varenna School
when Giovanni Polvani, the founder of the new
era of the Italian Physical Society, opened the
first course (August 19,1953) was plunged in an
historical stage of the modern physics.
It will be enough mentioning the titles of the
first 2 courses. The first, in 1953, directed by G.
Puppi, devoted to ``Detection of elementary
particles and Cosmic radiation'', with the participation of, among others, M. S. Blackett and
C. F. Powell (both already Nobel Prizes), H.
Alfven (Awarded Nobel Prize in 1970), G. Occhialini, G. Bernardini, Ch. Peyrou, Y. Goldsmith, E. Amaldi, D. A. Glaser, G. Wataghin; the
second, in 1954 (also directed by G. Puppi) on
``Detection on elementary particles and their
interaction artificially produced and accelerated'', with the participation of E. Fermi
(Nobel Prize in 1938), B. Rossi, E. Amaldi, B.
Adams, T. G. Pickavance, R. Levi-Setti, G. Salvini, E. Persico, N. Dalla Porta, J. Steinberger
(Nobel Prize in 1988), A. De Benedetti.
Let me quote what G. Bernardini said on the
occasion of the 30th anniversary celebration
remembering those courses:
``.....The first two lectures (of the second
course) were given by Fermi on ``Pions and
Nucleons''. I do believe that for him it was
natural to extend to the interaction between
nucleons through pions the concept of Quantum
Electrodynamics on which he wrote in 1932 an
article which, for the influence it exerted in the
future, has been recently referred by Pontecorvo
as the ``Roman Bible''.
I would have liked to quote also the words of
G. Puppi on that occasion, with special reference
to the year 1954 as the year of ``Enrico Fermi'',
but since Salvini already reported the same passege, the reader is referred to his section 2.
To complete the topical aspects of the beginning of Varenna School, I have to mention the
first course on Nuclear Physics (the 3rd of the
School) in 1955, directed by C. Salvetti and devoted to ``Nuclear structure problems and lowenergy nuclear processes'' with the participation
of Aage Bohr (Nobel Prize in 1975), I. Rabi
(Nobel Prize since 1944), C. H. Townes (Nobel
Prize in 1964), L. N. Cooper (Nobel Prize in
1972) J. Horowitz, D. M. Brink, A. De Shalit, S.
De Benedetti, A. M. Weinberg, M. Cini, S. Fubini,
H. J. Lipkin, among the Varenna lecturers.
17
IL NUOVO SAGGIATORE
It was the beginning of nuclear structure investigations not yet with powerful particle accelerators, but with some emphasis on nuclear
moments and their importance on the structure
of matter, as shown by the participation of two
future Nobel Prizes in different fields like
Townes and Cooper, who lectured on ``Nuclear
radius'' and ``Molecular structure and nuclear
moments'' the first, and on ``m-mesonic atoms''
the second.
18
The 4th course, in 1956, was the first on
Condensed Matter. It was directed by Luigi
Giulotto, a pioneer of solid-state physics in Italy
and devoted to ``Magnetic properties of matter''
with the participation of M. H. L. Pryce, J. K. Van
Vleck (Nobel Prize in 1977), C. Kittel, L. Neel
(Nobel Prize in 1970). E. M. Purcell (Nobel
Prize since 1952), A. Abragam, A. Kastler (Nobel Prize in 1966).
As you con see quite a number of Nobel Prizes, at least 40 as far as I could check, have
honoured the Varenna Courses since the beginning. This is a continuous tradition and, what is
more important, not only for the appreciation of
the School worldwide but also for the perception of important topics and the selection of
lectures. The large number of people awarded
with Nobel Prizes after their participation to the
School (in some cases few years later) is really
gratifying for the image and the scientific heritage of Varenna and of the Italian Physical Society. Some of them have been in Varenna more
than once, as a demonstration of their personal
interest in the School.
3. ± The Varenna courses and the evolution of
contemporary physics
I have not too much to say about the connection between the Varenna Courses and the
evolution of elementary particle physics, since
Nicola Cabibbo will illustrate this peculiar aspect in a very exhaustive way.
Let me only mention that just in the 50's two
milestones were laid for the development of the
Italian and European physics research: INFN
(Istituto Nazionale di Fisica Nucleare) in 1951,
thanks to the efforts of Amaldi, Bernardini and
Rostagni and CERN in 1954. The peculiar aspects of these ventures from the scientific and
organization point of view were matter of discussion in Varenna, as shown by other courses
like the one directed by A. Borsellino on the
``Quantistic theory of particles and fields'' in
1958, with the presence of W. Pauli (Nobel Prize
in 1945), B. Touschek, G. Racah, E. R. Caianiello, A. S. Wightman and that directed by
B. Touschek also in 1958, on the ``Physics of
Pions'' with the participation of S. Fubini,
R. Gatto, W. Thirring, G. Puppi, J. Ashkin,
among others. In fact, at that time, the 1000 MeV
electrosynchrotron of Frascati was put in operation (1958) under the direction of Giorgio
Salvini, and in 1961 the first electron-positron
storage ring (ADA) was realized following the
pioneering work of B. Touschek to open the way
to the e+-e± first collider (ADONE) at 1500 MeV,
under the direction of Fernando Amman, and to
the big collider physics at CERN.
Moreover, a course like that directed by L.
Radicati on ``Weak Interactions'', with the participation of L. Rosenfeld, B. Touschek, J. A.
Wheeler, R. H. Dalitz, R. Gatto, L. M. Lederman
(Nobel Prize in 1988) and J. Steinberger, was
certainly of particular interest since it was followed by other courses on the same subject
(T.D. Lee in 1964, M. Baldo-Ceolin in 1977) to
finally conclude with the famous meeting organized in Bologna in 1984 on the occasion of the
50th anniversary of weak interaction theory (see
later).
These are the years of the first experimental
production of antiparticles (E. SegreÁ and D.
Chamberlain) and of the discovery of parity
violation (T. D. Lee, C. Yang, L. Wu), as well as
the identification of the neutrino (anti-neutrino)
by F. Reines and C. Cowan.
Then it is in the 60's that a number of Varenna
courses were devoted to the development of the
different branches in physics.
Some examples:
a) Nuclear Physics. After the first already mentioned, there followed a series of significant
events in the field: the 1960 course directed
by G. Racah on ``Nuclear Spectroscopy'' did
present the interesting comparison between
the shell-model effective interaction as presented by the pragmatic school of Rehovot
(I. Talmi) and the nuclear collective phenomena interpretation of the Copenhagen
School (B. Mottelson, Nobel Prize in 1975)
together with the nuclear phenomena related
with electromagnetic properties (G. Morpurgo) and b-decay (G. Alaga and H. Daniel). The
pure shell-model approach (Talmi) and the
collective models including the pairing plus
IL NOSTRO MONDO
Fig. 3. ± Participants to the 1961 course on ``Nuclear Physics'' directed by V. Weisskopf.
quadrupole interaction (B. Mottelson) were
more specifically discussed later in the 1976
course on ``Elementary modes of excitation
in nuclei'', directed by A. Bohr. Subsequently
the 1961 course directed by W. Veisskopf
(and temporarily by A. De Shalit) on ``Nuclear
Physics'' was a kind of presentation of the
status of the art of the different facets of the
nuclear-matter behaviour. The main topics
were: Hartree-Fock shell-model calculations
(F. Villars); nuclear moments (A. De Shalit);
collective motion and many-body techniques
(G. E. Brown), compound-nucleus and random-phase approximation, shell-model and
deformation... This was a particular event
also from my personal point of view because
it was my first participation, as a student, to
the Varenna School (see fig. 3).
It was followed by 2 courses which could be
considered a series of text books in nuclear
physics starting from the course on ``Manybody description of nuclear structure and
dynamics'' (1965, director C. Boch from Saclay with, F. Villars,V.Gillet, P. Elliott, A
Migdal, D. Brink as teachers) to that on
``Nuclear Structure and Reactions'' (1967,
directors M. Jean from Orsay and R. A. Ricci)
with the presence of D. A. Bromley (speaking
about the new nuclear physics with heavy-ion
accelerators), H. A. Weidenmuller (on isobaric analogue resonance).
One of the main important aspects of such
courses was the assessment of the nuclear
physics research in Italy especially concerning nuclear spectroscopy with heavy-ion
beams and involving a fruitful collaboration
between the groups of Naples, Florence, Padua, Amsterdam, Orsay, Munich and Yale.
The advent of the heavy ion opened a new era
in nuclear physics investigations, for instance, using the in beam g-ray spectroscopy
technique invented by Morinaga and Gugelot(1).
That was clear in the succeeding course in
1974, directed by H. Faraggi (Saclay) and
myself.
The presence, as teachers, of M. Lefort (Orsay-Caen), H. Morinaga, S. G. Nilsson, N.
Cindro, D. Kurath, P. Armbruster (one of the
discoverers of new superheavy elements), M.
Harvey, U. Facchini, did ensure an outstanding level of the lectures and surely was
an important step related to the new perspectives of nuclear structure and dynamics
investigations.
b) Atomic and Condensed Matter Physics. At
this point I have to mention the very specific
connection with important developments in
this field of some peculiar courses of the
Varenna School. Already in 1957 a specific
course on ``Solid State Physics'' was held
under the direction of Fausto Fumi with the
19
IL NUOVO SAGGIATORE
20
participation of F. Seitz, N. F. Mott (Nobel
Prize in 1977). A. Schrieffer (Nobel Prize in
1972), E. Madelung, E. Wigner (Nobel Prize
in 1963), W. Kohn and J. Friedel, discussing
on metallic and non-metallic states, optical
properties of solids, radiation effects on solids, dislocation effects, superconductivity
and semiconductors. The peculiar event was,
of course, the first presentation of the BCS
theory on superconductivity.
A more specific course on ``Semiconductors''
was that directed by R. A. Smith in 1961 and
an assessment on ``Quantum Electronics and
Coherent Light'' was discussed in 1963, under
the direction of C. H. Townes (one of the
most frequent visitor of Varenna, who got the
Nobel Prize just one year later). At this
course there were: A. L. Schawlow (Nobel
Prize in 1981), N. Bloembergen (Nobel Prize
in 1981), W. E. Lamb (Nobel Prize in 1955)
together with T. Arecchi, O. Svelto and G.
Toraldo, among others.
This was the beginning of a series of courses
which were held along the history of the
physics of matter.
In fact in 1960 the XVII course directed by
Adriano Gozzini on ``Topics on Radiofrequency Spectrometry'' was already related
to the optical resonances, atomic beams and
mass spectroscopy, with the participation of
K. Shimoda, A. Kastler, C. Cohen Tannoudji
(Nobel Prize in 1988), A. Abragam and C. H.
Townes who, in 1963, just one year before
getting the Nobel Prize, directed the Course
on ``Quantum Electronics and Coherent
Light'', a milestone in the field, suffices it to
mention the participation of A. L. Schawlow
and of N. Bloembergen (Nobel Prizes in
1981) lecturing on ``Optical Pumped and
Solid-State Masers'' and on ``Non Linear
Optics'', respectively.
On the other hand, the ``Optical Properties of
solids'' were the subject of the 1965 course
directed by J. Tauc, with the participation of
W. Paul (Nobel Prize in 1989) and dealing
with band structure and interband transitions
(our chairman Franco Bassani gave, I think,
his first Varenna lecture on such a topic) and
semiconductors, whereas the ``Quantum
Optic'' phenomena dealing with coherent
states and fields, non linear optical processes, the quantum theory of lasers and related topics were the subject of the 1967
Course directed by R. J. Glauber.
Other pioneering topics at that time were
covered by B. Lax, G. Toraldo di Francia, W.
E. Lamb jr., F. T. Arecchi, O. Svelto, as
semiconductor lasers, optical resonators,
optical masers semiconductors. Another
course, held in 1975, that is worth mentioning
is that on ``Non-Linear Spectroscopy'', directed by N. Bloembergen (Nobel Prize in
1981), with the participation of T. W. Hansch,
F. Bassani, Y. R. Shen.
c) Astrophysics. One should also mention that
in this period topics like ``Space exploration and the solar system'' dealing with
plasma physics, solar corona, solar cosmic
rays and planetary atmospheres, were the
subject of a specific course in 1962, directed by Bruno Rossi, with the participation
of J. A. Van Allen, R. Jastrow, R. Lust and
C. Righini.
That course did represent the starting point
of a series devoted to astrophysics. Let me
mention the 1965 course on ``High Energy
Astrophysics'', directed by L. Gratton, dealing with radio galaxies, quasi-stellar sources,
neutron stars, quasars, neutrino-astrophysics
and especially with X-ray and g-ray astronomy, as shown by the presence of W. A.
Fowler (Nobel Prize in 1983) and R. Giacconi (Nobel Prize in 2002), together with E.
M. Burbidge, K. S. Thorne, N. Dalla Porta and
D. W. Sciama.
A course on ``General Relativity and Cosmology'' was held in 1969 and directed by R.
K. Sachs, where also the question of detecting gravitational waves was discussed.
That topic was the specific subject of a 1972
course directed by B. Bertotti on ``Experimental Gravitation'' with the participation,
among others, of J. Weber, L. Halpern, R. W.
Davies and W. M. Fairbank.
On the other hand, an important course on
``Physics and Astrophysics of Neutron Stars
and Black Holes'' was held in 1975 and directed by R. Giacconi and Remo Ruffini,
where S. Chandrasekhar (Nobel Prize in
1983) was also present.
d) Other subject. In fact, during the 70's a
number of courses on different aspects
concerning physics were held, namely on the
``Foundation of Quantum Mechanics''. This
was the title of the 1970 course directed by
IL NOSTRO MONDO
Fig. 4. ± Participants to the 1972 course on the ``History of Twenty Century Physics''.
B. D'Espagnat . Let me mention that, among
the lecturers, you could find E. Wigner (Nobel Prize in 1963) and L. De Broglie (Nobel
Prize in 1929), together with J. M. Jauch, B.
S. De Witt, A. Frenkel. That course was followed by the one on ``Problems in the foundation of Physics'' in 1977, directed by G.
Toraldo di Francia with the presence of E.
Amaldi, M. Jammer, J. M. Levy-Leblond, J. A.
Wheeler and I. Prigogine.
Other fields covered at the time were the
``Physics of High Energy Density'' directed
by P. Caldirola and H. Knoepfel with the
participation of E. Teller and R. Gratton and
``Health and Medical Physics'' in 1975 directed by J. Baarli, which was followed by
another course on ``Medical Physics'' in
1979, directed by J. R. Greening, where an
extensive program dealing with the various
physics techniques applied to the diagnostic
and therapy was presented (image formation, tomography, radiotherapy, nuclear
cardiology .....).
Perhaps an important step was also achieved
in the field of the History of physics with a
specific course held in 1972, devoted to the
``History of twenty century physics'' directed
by C. Weiner and with the participation, as
lecturers, of P. A. M. Dirac (Nobel Prize in
1933), H. B. G. Casimir, J. Bromberg, G.
Holton, E. Amaldi, L. Kowarski, W. Goldstein
and W. Weisskopf. (See fig. 4).
4. ± The 80's and the more advanced Courses
in the last XX century decade
I will start in considering this very interesting
period of the history of the Varenna School with
the course on ``Elementary Particles'' directed
by Nicola Cabibbo as he mentioned in his talk.
The reason is that it occurred just after the UA1
and UA2 experiment and before the award of the
Nobel Prize to C. Rubbia and S. Van der Meer at
CERN; also questions on supersymmetry and
supegravity were discussed, so as topics in detector physics as reported by G. Charpak (Nobel
Prize in 1992).
Concerning the field of high-energy physics, it
was in 1995 that an extensive course on QCD
was held with the title ``Selected Topics in nonPerturbative QCD'' and directed by A. Di Giacomo and D. Diakonov, whereas the ``HeavyFlavour Physics'' was the subject of the course
directed by I. Bigi and L. Moroni in 1997 dealing
with B-physics, rare K-decays and the heavyquark production (for instance at HERA). The
``Neutrino Physics'' has recently been reviewed
in the 2002 course directed by E. Bellotti, Y.
Declais and P. Strolin, some time after the pioneering courses on ``Weak Interactions'' already
mentioned, held in 1959, 1964 and 1977.
In fact it was in '84 that the Italian Physical
Society did organize in Bologna the very important Meeting devoted to the celebration of
the 50th Anniversary of the Fermi Theory.
21
IL NUOVO SAGGIATORE
22
``La Fisica Italiana e le Interazioni Deboli'' was
the title of the event where a large number of Italian protagonists of such a fundamental venture in
the history of physics were present : Edoardo
Amaldi, Milla Baldo-Ceolin, Gilberto Bernardini,
Nicola Cabibbo, Piero Caldirola, Carlo Castagnoli,
Marcello Conversi, Giuseppe Fidecaro, Ettore
Fiorini, Raoul Gatto, Alberto Gigli-Berzolari, Luciano Maiani, Giuseppe Occhialini, Emilio Picasso, Oreste Piccioni, Bruno Pontecorvo, Giampietro Puppi, Franco Rasetti. Bruno Rossi, Antonio Rostagni, Carlo Rubbia, Giorgio Salvini, Claudio Villi, Gleb Wataghin, Gian Carlo Wick, Emilio
Zavattini ed Antonino Zichichi (see fig. 5).
Of particular relevance is the series of courses
following the evolution of atomic and condensed matter physics.
The 1983 course on ``Highlights of Condensed
Matter'' was directed by F. Fumi, F. Bassani and
M. Tosi and could be considered an exhaustive
assessment of the field if one looks at the various lectures: density functional theory, electronic structure of nonmetals, chemical bonding, solitons and fractional charge, charge
transport in conductors, non linear optics and
dynamics, excitation and transport in quantum
liquids, quantum vortices, electron glasses, optical bistability, given by teachers like W. Kohn,
J. R. Schrieffer and J. Barden (both Nobel Prizes
in 1972), M. Schluter, D. Pines, T. Regge and L.
Lugiato.
On the other hand quite a number of important
courses were held in the 90's concerning atomic
physics as that directed by A. Arimondo and W. D.
Phillips (Nobel Prize in 1997) and Strumia in 1991
on ``Laser Manipulation of Atoms and Ions'', with
the participation of N. F. Ramsey (Nobel Prize in
1989) and the two future Nobel Prizes, C. CohenTannoudji and W. D. Phillips.
The ``Frontiers in Laser Spectroscopy'' were
discussed in the following year (1992) in the
course directed by T. W. Hansch and M. Inguscio,
with the participation of L. Schawlow (already
Nobel Prize), whereas in 1988 a specific course on
``Bose-Einstein Condensation in Atomic Gases''
was directed by M. Inguscio, S. Stringari and C. E.
Wieman (who got the Nobel Prize in 2001). At this
course, just dealing with that important discovery,
the participation of E. Cornell and W. Ketterle
(Nobel Prizes in 2001) gives the idea of the scientific level of the lectures.
In 1991 the course directed by A. Stella on
``Semiconductors, Superlattices and Interfaces''
was also a significant event with reference to
the superlattice physics, as shown by the presence of the pioneer of that field, L. Esaki (Nobel
Prize in 1973).
Moreover the nanostructure physics was the
main topic of the last course in 2002, directed by B.
Deveaud-PleÂdran and A. Quattropani. It was devoted to ``Electron and Photon Confinement in
Semiconductor Nanostructures'', with new results
of new perspective in that field.
I have to mention also the 1997 Course on
``Modes and Phenomenology for Conventional
and High-Temperature Superconductivity'',
directed by G. Iadonisi and R. J. Schrieffer, with
the participation of G.C. Strinati, Y. Liang, A.
Barone, Z. X. Shen, A. S. Alexandrov , T. M. Rice,
among others.
Another topic, whose interest was increasing
in recent years, is that concerning disordered
and chaotic systems. A course on ``Quantum
Chaos'' was directed in 1981 by G. Casati, I.
Guarneri and U. Smilanski, whereas ``The Physics of Complex Systems'' was the subject of the
courses in 1996 and 2003 both directed by F.
Mallamace and H. E. Stanley, with the participation of P. G. De Gennes (Nobel Prize in 1991)
and K. A. Muller (Nobel Prize in 1987).
It is interesting to note that Alex Muller was
the director, together with Rigamonti, of the
course on ``Local Properties at Phase Transitions'' in 1979, where also De Gennes was present lecturing on mesoscopic phases.
Muller got the Nobel Prize in 1987, just when he
was participating in the National Congress of the
Italian Physical Society in Naples, giving there a
general report on ``high-T superconductivity''.
Let me conclude with some emphasis on the
nuclear physics courses. In 1984, one of the
most successful years of the scientific policy of
the Italian Physical Society, as we have already
seen, a course on ``From Nuclei to Stars'' directed by A. Molinari and myself, was dedicated
to H. Bethe (Nobel Prize in 1967) , who lectured
on ``Supernova Theory''.
Flashes on Bethe contributions to physics
were presented by E. Amaldi.
This also was a reference course including topics like nuclear models, pion and quark effects in
nuclei, nuclear matter under extreme conditions,
element synthesis, superheavy nuclei (the Z = 108
element was just discovered). Among the lecturers
I can mention I. Talmi, H. Feshbach, T. E. O.
Ericson, L. Van Hove, B. Coppi, H. Morinaga, P.
Armbruster, M. Hack, A. Covello.
IL NOSTRO MONDO
23
Fig. 5. ± Flashes of the Bologna meeting of the Italian Physical Society celebrating the 50th anniversary of the Weak
Interactions Physics.
IL NUOVO SAGGIATORE
Another event did occur in the same time: the
dedication of the street along Villa Monastero to
Giovanni Polvani, the founder of the School (see
fig. 6).
There were two significant courses in 1987
concerning the frontiers of nuclear and manybody physics.
The first was ``Trends in Nuclear Physics'',
directed by P. Kienle, A. Rubbino and myself
and was particularly interesting since the borderlines of nuclear physics were analyzed in
details from the high-energy frontier as lectured
by Carlo Rubbia (Nobel Prize in 1984), the
subnucleonic degrees of freedom in nuclei as
lectured by B. Povh and the Quark Gluon Plasma deconfinement (R. Stock) to the superheavy
nuclei, which were reviewed by two of the pioneers in the field, i.e. P. Armbruster and Y.
Oganessian. That Course started on June 23,
coinciding with my 60th birthday, which was
also discretly celebrated in a friendly atmosphere (allow me this personal touch!).
The second was that directed by R. A. Broglia
and J. R. Schrieffer (once again!) on ``Frontiers
and Borderlines in Many-Particle Physics'' and
topics like lattice interactions, quantum machanics of macroscopic variables, heavy fermions, phase transitions in nuclei, quantum ef-
fects in heavy-ion reactions, Mott-phenomena,
relativistic effects in nuclei and rotating superconductors were treated. Among the lecturers
A. J. Legget, T. M. Rice, D. M. Brink, G. Bertsch,
P. W. Anderson, G. Baym were present.
That course was repeated in 1992 with the
same directors and almost the same title (``Perspective in Many-Particle Physics''), with also
the participation of B. Mottelson (Nobel Prize in
1975) with more emphasis in the many-body
phenomena in nuclear and condensed matter.
Concerning borderline topics this period was
full of courses dealing with frontier-physics.
I will consider just few examples.
In 1989 there was a course on ``Solid-State
Astrophysics'' directed by E. Bussoletti and G.
Strazzullo dealing with interstellar grain and
ices , asteroids, meteorites, interplanetary and
cometary dust, space exploration of comets and
primitive minor objects.
In the same year a course on ``High-Pressure
Equation of State: Theory and Applications''
directed by S. Eliezer and myself did cover the
use of EOS in different fields: chemistry, plasma
astrophysics, geophysics, planetary physics,
nuclear, hadronic and quark matter.
That topic was of a large interest, as shown by
another course held in 1990 and directed by J. C.
24
Fig. 6. ± The dedication of the street along Villa Monastero to G. Polvani during the course ``From Nuclei to Stars''.
IL NOSTRO MONDO
Gille and G. Visconti on ``The Use of EOS for
Studies of atmospheric physics'', with some
connection with a successive one, in 1993, directed by G. Fiocco and G. Visconti concerning
the ``Diagnostic Tools in Atmospheric Physics''.
The general importance of such courses cannot
escape if one consider problems like global climate, atmospheric dynamics and corresponding
observations.
In 1995 a course on ``Dark Matter'' was held,
under the direction of S. Bonometto and J. Primack and, in 1996, one on ``Past and Present
Variability of the Solar Systems'' , directed by
G. Cini-Castagnoli, just to show the large spectrum of the Varenna Courses in the last period.
However, I cannot forget the course directed by
C. Salvetti and myself in 1990 on ``Status and
Perspectives of Nuclear Energy Fission and Fusion'' with the participation of E. Teller, M. Silvestri, G. Vendryes, R. Carl, F. I. Parker, M. Cumo,
F. Niehaus, C. Marchetti, Ph. Rebut, E. Bertolini, B.
Coppi, R. Toschi, R. Bock, C. Rubbia, F. Scaramuzzi, A. Bertin and A. Vitale. It was a special
occasion to give a message from a large scientific
community to the Italian political authorities and
to the public opinion in order to take care of the
energy problems without any discriminations of
the nuclear energy research and use.
Coming back to nuclear physics (my field
anyway!) I like to mention in conclusion at least
two courses. In 1997 (just ten years after that
corresponding to my 60th birthday, which
means that I was already 70 this time) a Course,
also directed by A. Molinari and myself was
devoted to ``Unfolding the Matter of Nuclei''.
This was also a complete review of the state of
the art of nuclear physics from the standard and
improved shell-model to the more algebraic
methods introduced by symmetries, to the quark
effects and composition of nuclear matter, the
hadron-structure QCD, the quark deconfinement, so as the nuclear astrophysics, the production of new superheavy elements, hypernuclei, quark . Among the lecturers, I. Talmi, F.
Iachello, B. Frois, P. Armbruster, Y. Oganessian,
A. Kerman, J. Negele, H. Satz, F. Close, S. M.
Blanky, J. Vervier, T. Bressani, A. Covello,
M. Pignanelli, F. Palumbo were present. It was
gratifying for me to give a talk on the ``hundred
years of Italian Physical Society'' with some
recollections that could be complementary to
the present talk.
The last comment I would like to give, in conclusion, is that just one year ago, in 2002, another
course with the title ``From Nuclei and their
Constituents to Stars'' has been held and directed
once again by A. Molinari, together, this time,
with L. Riccati and with the participation of quite
a number of friends and colleagues (among
which: F. Iachello, R. A. Broglia, A. Covello, S. M.
Bilenky, M. Di Toro, T. Bressani, R. Stock, W.
Weise, J. P. Blaizot); that course was in fact
dedicated to myself and my career for the long
involvement (50 years) in nuclear physics.
Let me finish by dedicating my present talk
here to the 50 years of the Varenna School.
THE VARENNA SCHOOL AND PARTICLE
PHYSICS
N. Cabibbo
INFN e Dipartimento di Fisica
UniversitaÁ ``La Sapienza'',
P.le A. Moro, 2 00185 Roma
1. ± Varenna and the reconstruction of European physics.
The principal task of the post-war European
Ð and Italian Ð physics was that of reconstructing an infrastructure of institutions
and research centers which could bring back
that center of physics research which the destructions of the war and the forced emigration
of so many of the most talented physicists had
inexorably pushed to the other side of the
ocean.
The combined effect of the Manhattan project
and of the evolution of physical instrumentation,
in particular the development of ever more
powerful particle accelerators, had in the
meantime radically changed the way in which
physics research was carried on. The university
groups, such as those in Florence or Rome, or
even the Cavendish in Cambridge, could not any
more compete alone with powerful organizations such as the Brookhaven or the Berkeley
laboratories in the United States. The neutron
work by the Fermi group was a miracle which
could not easily be repeated. The miracle had in
fact been repeated in the immediate post war
years with the Conversi-Pancini-Piccioni experiment, and with the development in the UK,
with an essential and never enough recognized
contribution by Beppo Occhialini, of the nuclear
emulsions, which led to the discovery of the
25
IL NUOVO SAGGIATORE
26
pion. These fundamental and much admired results were in fact the swan song of the old way of
doing physics. For remaining competitive, a new
scale of operations was needed, and this led to
the creation of institutions and research centers
such as CERN at an European level, INFN and
the Frascati synchrotron laboratory in Italy.
A second hurdle had to be faced: while across
the ocean physics had been enriched by the influx of European eÂmigreÂs and the experience of
the war effort had reinforced the links between
the different schools, European physics had
been impoverished by the emigration; the lively
prewar network of scientific relations had been
disrupted. A new generation of young physicists
had to be raised to fill-in the gaping holes left by
the war, and new links had to be created between the research groups in Europe, and between them and the groups in Japan and the
United States. One of the tools which contributed to the achievement of this task was the
establishment of summer schools where a selected group of young physicists led for a few
weeks a common life while being exposed to the
teaching of some of the great masters, and to the
most recent developments in physics.
The Varenna School, which started its operations in 1953, was among the first, with Les
Houches, in post-war Europe. The example was
followed by the Scottish Universities school in
1960, by the Cargese School, by Erice in 1963,
and at present the number of summer schools
has grown to the point that each European
physicist is able to take part in them during the
formative years of his career. In the United
States, where the summer school movement had
started before the war at Ann Harbor, the number of schools has also dramatically increased
starting in the early sixties. The creation of the
International Center for Theoretical Physics at
Trieste has encouraged the extension of the
summer school movement to less developed
countries in Africa, Asia and Latin America.
The year I graduated, in 1958, I took part in a
summer school at Varenna, the IX course, on
Pion Physics, organized by Bruno Touschek, my
thesis advisor. The next year I took part in the XI
course on weak interactions, organized by Luigi
Radicati. In 1960 Ð there was no course on
elementary particles in Varenna that year Ð I
was in Edinburgh for the first course of the
Scottish Universities summer school. These
were wonderful experiences, I learned a lot of
physics, I started to form my taste with respect
to what I liked more or less in theoretical physics, but most of all I established friendships
which lasted over the years, with people such as
Derek Robinson, Peter Higgs and M. Veltman,
Shelley Glashow and Nick Burgoyne, Nino Zichichi, Giorgio Bellettini and Vittorio Silvestrini.
I also had the chance of getting to know some of
the impressive teachers, among which Archibald Wheeler, Jeff Steinberger, Leon Lederman,
Walther Thirring (who one night gave a piano
concert which was interrupted by a large bat
while he was playing the Fledermaus), Jeff
Chew, David Jackson. A great experience for a
young physicist!
2. ± Varenna and high energy physics
The first two courses of the Varenna school
took place in 1953 (starting on August 19, nearly
exactly fifty years ago) and in 1954. Under the
direction of Giampiero Puppi, they lasted three
weeks each. The programs where coordinated,
the first course focusing on the cosmic ray
searches and the related techniques,the second
on accelerator experiments. The cast of lecturers was stellar, and included six Nobel prize
winners: Blackett, Powell, Glaser, Alfven, Fermi, Heisenberg, and some of the grand masters:
G. Occhialini, F. G. Houtermans, G. Bernardini,
E. Amaldi, B. Rossi, J. Adams, M. Ceccarelli, G.
Salvini, E. Persico.
This very high standard was upheld in the
following years. The fourth course, on nuclear
structure (1955, director: C. Salvetti) included
lectures by A. Bohr, L. Cooper, I. Rabi, C.
Townes. The fourth, on magnetism (1956, director: L. Giulotto), had lectures by L. NeÂel, E.
Purcell, A. Kastler, A. Abragam. So on with the
fifth, (1957, director F. Fumi), on solid state
physics, with lectures by J. Schrieffer, F. Seitz,
C. Zener, and on and on.
It is clear, from the program of the first
courses, that the Varenna School was not conceived as a school in High Energy Physics, but
that it intended to cover all aspects of physics,
according to the aims and statutes of the Italian
Physical Society. Over the years the courses
have covered nuclear physics, plasma physics,
different aspects of the physics of condensed
matter, astrophysics, information theory, including quantum computation, optics, acoustics, earth sciences, medical physics, practically
the whole spectrum of physics research.
IL NOSTRO MONDO
2) 1963-1972: 29 courses, of which 8 (26%) on HEP.
3) 1973-1982: 30 courses, of which 5 (16%) on HEP.
4) 1983-1992: 36 courses, of which 1 (3%) on HEP.
5) 1993-2002: 30 courses, of which 4 (13%) on HEP.
In this talk I will concentrate on high energy
physics, and the related subject of quantum field
theories. I count 24 Varenna courses devoted to
these subjects, approximately 15% of the total
number up to 2002. The level of these courses
has been very high. Among the lecturers one can
identify 23 presences by physicists who had received a Nobel Prize, a good measure of the
prestige enjoyed by the School, or who received
a Nobel prize in the following years, a sure sign
of keen judgment on the part of the organizers.
Among the latter group S. Glashow, L. Lederman,
A. Salam, M. Schwartz, J. Steinberger, M. Veltman, E. Wigner, H. A. Bethe. Four of the courses
(XXIX-1963, XXXII-1964, XXXIII-1964, XLI-1967)
were directed by scientists who had received a
Nobel prize, or would receive one in the following. Among the mythical icons of physics that
have honored the School with their teaching, I
have already mentioned Fermi and Heisenberg,
but I would like to recall that W. Pauli was in
Varenna in 1958 at the VIII course, L. de Broglie
took part in the IL course in 1970, and P. A. M.
Dirac lectured in the LVII course in 1972.
The presence of high energy physics and field
theories in Varenna has not been evenly distributed through the five decades of the School.
Including under the HEP heading courses on the
physics of elementary particles and the related
experimental techniques as well as courses on
the role of elementary particles in nuclear physics and courses on field theories, one can find:
1) 1953-1962: 28 courses, of which 6 (21%) on HEP.
It is clear that the impact of the Varenna
School on the development of elementary particle physics, and on the formation of its young
practitioners, which was very substantial in the
first two decades of its life, began to slide in the
third.
As a personal recollection, I could not avoid
to be surprised when in 1983 Renato Angelo
Ricci asked me to organize a course on elementary particles for the following year; it had
been my impression that the Italian Physical
Society had decided to phase out the subject in
the Varenna courses, perhaps recognizing that
the Erice school had over the years acquired a
well deserved leadership in the field. Renato
insisted on the importance of reaffirming the
presence of elementary particles in a School
dedicated to the memory of Enrico Fermi. So I
became responsible for the XCII course, the
lone HEP course in the 4th decade of the school.
Only ten years after, in 1994, the subject started
picking up some momentum in Varenna, with
four courses held since then. A course on neutrino physics was held last year, while next year
we will have a course on hadron physics.
3. ± The development of elementary particle
physics.
It is interesting to outline the development of
particle physics through the fifty years of activity of the Enrico Fermi School. A review of
the progress of high energy physics through the
five decades dispels the possible perception that
the field reached a peak at the end of the seventies with the establishment of the unified
theories of the fundamental interactions and
that little happened after that. Individual laboratories, even large ones as in the case of
CERN or Fermilab, have seen alternations of
very productive periods and less exciting ones,
but considering the wide front which spans from
accelerator and collider experiments to the
large underground laboratories, the progress
has been continuous.
While CERN is preparing the LHC collider and
the related large detectors, the excitement of
discovery has moved to the B-factories at Stan-
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IL NUOVO SAGGIATORE
ford and Tsukuba, where large numbers of mesons containing the b-quark have been produced
and analyzed, and to the underground laboratories which in the recent years have led to a
veritable revolution in neutrino physics. With
the completion of LHC the pendulum will swing
back.
3.1. ± Particles today.
28
To frame the historical outline, let us briefly
recall the present status of our knowledge of
elementary particles. As far as we now know,
matter is made up by elementary particles,
fermions of spin 1/2, acted upon by forces of
four types: gravitational, weak, electromagnetic, strong. When we say matter, we intend all matter, including the entire universe.
We should remember that we are still lacking
a satisfactory quantum theory of the gravitational interaction, a sign of the incomplete state
of our theoretical understanding. Many are
convinced that superstrings, when fully developed, will provide an all-inclusive description of
all forces, including the gravitational forces, but
we are not there yet. Since gravitational effects
in the world of particles are extremely weak and
essentially undetectable, we will omit them in
the following.
There are two types of fermions, the leptons
and the quarks. The quarks only appear in
composites such as the baryons, which include
the proton and the neutron, the building blocks
of the atomic nucleus, and contain three quarks,
and the mesons, which contain a quark-antiquark pair. Quark composites are collectively
called hadrons. Hundreds of hadronic states are
known at present. The leptons include three
electrically charged particles, the e ; ; , and
three neutral very light particles, the neutrinos.
The different types of quarks and leptons are
called flavors; quarks and leptons are organized
in three families, each of them containing a negatively charged lepton, a neutrino, and two
quarks with charge, respectively, equal to 2e/3
and e/3. Each quark flavour appears in three
copies called colors, and the symmetry among
the three colors is the basis for Quantum Chromo Dynamics (QCD), the theory of the gluonic
forces which bind quarks inside hadrons, and
are responsible for the nuclear forces.
The three families are not independent, being
interwined by a phenomenon, now known as
``quark mixing'', that I discovered in 1963, and
presented at the 1964 course in Varenna (the
XXXII) directed by T. D. Lee. In 1973 Kobayashy
and Maskawa demonstrated that quark mixing
offers a natural explanation for the violation of
matter-antimatter (CP) symmetry.
The three families are also connected by a
second network of mixing, between leptons, as
proposed by Bruno Pontecorvo in 1967. Lepton
mixing leads to the recently discovered phenomenon of neutrino oscillations.
To the fields of force there correspond one or
more types of quanta, collectively known as the
elementary bosons: the photon is the quantum
of the electromagnetic force, the W‡ , W , and Z0
are the quanta of weak interacting forces, and
the eight gluons are the quanta of the forces
which bind quarks inside baryons.
The modern theory gives in principle a complete description of these phenomena in a welldefined mathematical frame Ð the so-called
Standard Model, where force fields are closely
connected to the existence of a set of symmetries of the particles, including the color symmetry which is the origin of the inter-quark
gluonic forces described by QCD. Only approximate solutions to the equations of the Standard
Model are available, and an important role in the
comparison of the theory with experimental
data is played by massive computer simulations.
These simulations, to offer but one example,
have been essential in obtaining information on
the confinement of quarks (and of gluons) inside
the hadrons.
3.2. ± Particles over the decades.
How did we get to where we are now, starting
in 1953? The theoretical framework of the
standard model, including an accurate prediction of the large masses of the W , and Z0 bosons was essentially complete at the end of the
second decade of the Fermi School, but details,
sometimes surprising even if not completely
unexpected, as in the recent discovery of neutrino oscillations, have been accumulating up to
now, and given the incompleteness of the existing theory we expect exciting new breakthroughs in the future. I wold like to outline the
progress of the field over the five decades of the
school. Given the short time at my disposal, I
will only present with few comments a list of the
main acquisitions and research themes in each
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decade, a list, I repeat, which aims to demonstrate that the progress in the field has continued with remarkable success through the five
decades. Even with in these limits the list is
necessarily incomplete.
To set the scene, let me recall that the years
which preceded the first course in 1953 had
witnessed important results, which included the
discovery of the pion, and the first indications of
the leptonic nature of the muon through the
Conversi-Pancini-Piccioni experiment, the discoveries of the first strange particles in cosmic
radiation, the work by Enrico Fermi on pionproton scattering which led to the discovery of
an excited nucleon, now called the -particle.
3.3. ± From 1953 to 1962
This was a decade of intense exploration, and
unexpected discoveries Ð the violation of parity in weak interactions. The tools which dominated the subsequent developments were devised during this decade, starting with the synchrotron, the early colliding rings, in particular
ADA, the prototype of the electron-positron
colliders, the bubble chamber which started
giving its fruits.
Experiment: Discovery of the neutrino, strange
particles, violation of parity symmetry, -nucleon scattering, photoproduction, discovery of
muon neutrino.
Theory: Quantum Electro-Dynamics, dispersion
relations, V A theory of weak interactions,
Regge poles.
Tools: Syncrocyclotrons, synchrotrons, colliding rings, bubble chambers.
3.4. ± From 1963 to 1972
The decade is dominated by hadron physics,
with the discovery of large numbers of new
mesons and baryons, and by the development
of deep inelastic scattering of electrons and
neutrinos for exploring the structure of the
nucleons. One unexpected discovery: the violation of CP symmetry. On the theoretical side
this decade is characterized by important developments, such as the quark model and the
first successful formulations of gauge theories
of the fundamental forces.
Experiment: Multiplication of hadron states,
deep inelastic scattering, violation of CP symmetry.
Theory: The quark model, charm, quark mixing,
neutrino oscillations, unified electroweak theory,
the parton model.
Tools: e‡ e colliders, Adone to SPEAR.
3.5. ± From 1973 to 1982
During this decade the unified theory of
electroweak interactions is consolidated with a
number of experimental results, such as the
discovery of neutral current weak interactions
and of the charm quark. The theoretical proposal of a third lepton-quark family, which through
quark mixing could explain the violation of CP
symmetry, finds a brilliant confirmation with the
discovery of a third charged lepton, the , and a
fifth quark, the b. New high energy colliders,
LEP and the SPS proton-antiproton ring, built
during these years, will dominate experimental
physics in the next decade. The theoretical development of super-unified theories suggests
that the proton may be unstable, and renews the
interest in large underground laboratories.
Experiment: Discovery of neutral currents,
discovery of charm, discovery of lepton, tests
of electroweak unification, discovery of b quark.
Theory: Quantum Chromo Dynamics, grand
unification, proton decay, CKM matrix and CP
violation.
Tools: 4 detectors, LEP, the SPS collider.
3.6. ± From 1983 to 1992
This decade opens with the discovery of the
intermediate bosons of weak interactions, the
crown piece of the unified electroweak model.
The four LEP experiments start their activity
which over nearly fifteen years would lead to a
precision test of the Standard Model. Theoretical
physicists start a detailed exploration of QCD by
computer simulations. We begin looking beyond
the unified and grand-unified theories in the direction of super-symmetric models which will
dominate theoretical physics in the coming
years. There is a growing interest in the role of
elementary particles in the universe, both inside
the solar system Ð the solar neutrinos Ð and
29
IL NUOVO SAGGIATORE
beyond Ð the dark matter and inflationary
models of the Big Bang.
Experiment: Discovery of W, Z, LEP physics:
only three families, the Dark Matter.
Theory: Lattice QCD and quark confinement, super-symmetric models.
Tools: Underground laboratories: Gran Sasso,
Kamioka.
3.7. ± From 1993 to 2002
The last decade is very productive. It starts
with the discovery of the sixth quark, the t, and
closes with a number of important results: the
discovery of a new instance of CP violation in
the decay of neutral kaons, and the experimental confirmation of the violation of CP in the
mixing of neutral B-mesons, expected on the
basis of the quark mixing scheme.
The physics of neutrinos is in the midst of a
revolution, with the solution of the long-lasting
puzzle of the missing solar neutrinos and the
discovery of two types of neutrino oscillations.
Experiment: Discovery of top quark, direct CP
violation in K decay (0=), violation of CP symmetry in B decays, neutrino oscillations.
30
Theory: Tests of the unified electroweak theory,
taming the CKM matrix, string theory, KaluzaKlein theories.
Tools: LHC, muon colliders, neutrino factories.
4. ± The next decade of HEP at the Fermi
school
I would like to conclude with some considerations on the future of high energy physics in the
Varenna courses. The Italian Physical Society
might wish to keep its involvement at the relatively low level experienced in the eighties and
nineties, or it may decide a revival of Varenna's
impact on the field, back to the level it had in the
fifties and sixties. Either decision has its merits.
In favor of the ``business as usual'' is the consideration that while Varenna was essentially
alone in the fifties, now the Italian scene offers a
variety of schools, Erice certainly, but also the
winter school in the Aosta Valley, schools organized by INFN for its fellowship students and by a
consortium of physics departments for their
graduate students, not to mention the many
schools available in other EU countries.
If on the contrary the Italian Physical Society
chooses to renew the impact of the Varenna
school in HEP related subjects, it should try to
mark its difference from these excellent enterprises. Is this possible? perhaps yes, by emphasizing its international flavor, by a careful
choice of directors, or better of an international
board of directors, nominated for a well-defined
period, charged with the task of devising a midterm program which comprises a number of coordinated courses. The impact of the first two
courses, 1953-54, owes a lot to their careful coordination under a single director, the young
Giampiero Puppi, and the two courses I attended
in '58 and '59 as a student were organized in close
cooperation by Bruno Touschek and Luigi Radicati. While other schools are characterized by a
relatively stable ``faculty'' and choice of themes,
Varenna could aim at variety, mixed with some
element of continuity, identifying a few threads
which would alternate through the years, each
lasting for a certain limited number of courses.
The subject is as lively now as it was fifty years
ago. As an exercise I tried to build a program for
the courses in the next decade:
Hadron Physics: Already scheduled for 2004.
Astro-particle Physics: Including the role of CP
violation in the birth of normal matter and the
problem of dark matter.
The hunt for the Higgs Boson: LHC, Tevatron,
theoretical ideas.
Neutrino Physics: Solar neutrinos, earth based
neutrino experiments, violation of CP symmetry.
The new colliders: e‡ e colliders, muon colliders.
Super-symmetry: Theory and phenomenology
of LHC searches.
Quantum gravity and strings: Is there an experimental angle?
Physics at high energy density: Quark-gluon
phase transitions, experimental tests, cosmological implications.
Please, do not take this list too seriously: it is
not intended as a definite proposal, but only as a
proof of existence of a possible exciting program, a list of subjects I would love to learn
more about. I am convinced, however, that
better and more coordinated ideas would easily
emerge if the Italian Physical Society decides to
proceed in this direction.
IL NOSTRO MONDO
PRESENTATION OF THE COURSE
``RESEARCH ON PHYSICS EDUCATION''
E. F. Redish
University of Maryland, USA
Let me begin these brief remarks by offering
my congratulations to the Italian Physical Society on 50 years of the International School of
Physics ``Enrico Fermi'' held in this delightful
venue here in Varenna on Lake Como. Although
this course is the first I have attended in person,
I have fond memories of learning physics from
Fermi School proceedings while I was a graduate student. In particular, I still recall learning
dispersion relations from the volume edited by
Eugene Wigner.
Since the Fermi Schools have been so effective in teaching physicists how to do research, it
is now appropriate and fitting that here in the
50th anniversary year we should be holding the
first Fermi School on research on how to teach
physics.
Although our course focuses on research on
physics learning and on how to teach physics
more effectively, the connection to traditional
physics research is strong. Physics, after all, is
not only about finding out how the world works;
physics is finding out how we can best think
about how the world works. If it were the former, a large ``Wizard's book'' of ``what happens
when'' would suffice. But that is not physics.
Physics requires a coherence and an elegance
that is about creating and transforming our descriptions and rules until they fit comfortably in
our heads.
A colleague and I recently solved a minor
mathematical problem for a biologist trying to
understand his measurements of processes in a
cell Ð two coupled ordinary differential rate
equations. Solving them took a matter of only a
few minutes, but we spent an hour ``licking the
equations into shape'', like a mother cat rearranging the fur on a newborn kitten. We redefined our constants so the rate parameters
were defined by time constants with comparable units. We defined constants that specified
the initial and the limiting values of the variables. We rearranged both the starting equations
and my solution. When we were done, both our
equations and our solution were totally obvious.
The problem had been transformed until it was
trivial. I could write down the solution at any
time without re-deriving (or memorizing) it Ð
because it made sense to me. Moreover, in the
form we had created, the relationships between
the measured variables and the parameters of
the system were crystal clear and one could
easily tell what one was learning by the measurement.
The exercise described in the previous paragraph was a reasonably elementary one, similar
in style and scope to problems solved by research physicists every day. But I was taken
with it because I had only recently come to appreciate how much of the research physics we
do is about learning to frame things so they are
easy to think about.
This view that physics is about finding ways to
look at the world that ``matches human thinking'' is not restricted to the everyday activities of
the research physicist. Many of the grand leaps
in our understanding have this character. A
large fraction of the research done in physics
today is not at the ``unknown edge'' where we
believe new physics is to be discovered, in previously unexplored regimes such as cosmology,
ultra-high energy, or ultra-high matter density.
Rather, much physics research is about making
sense of physics that we in principle know. The
proposal of the Cooper pair, mentioned in an
early talk in this session (and discussed in early
Fermi Schools) provided a breakthrough in our
understanding of how to think about superconductivity. But the fundamental physics underlying the Cooper pair is simply the manybody non-relativistic SchroÈdinger equation of
electrons and nuclei with the Coulomb interaction. This, however, does not help us much,
unless we can ``find the physics'' Ð find the way
to rearrange an unthinkably complex set of unsolvable equations in a way that we can think
about them. Today, much of forefront physics
research is about finding new ways to think
about phenomena described in principle by the
well-known physics of classical mechanics (the
physics of chaos and complexity) and non-relativistic quantum mechanics (new quantum
states of matter, quantum computing).
This focus on ``finding a better way to think
about it'' isn't new. Newtonian mechanics was
first presented to the world as statements in
geometry. Soon thereafter, the tools developed
by Newton and Leibniz to help think about
classical mechanics took over. Lagrange and
Hamilton developed new ways to think about
well-established physics Ð in part to simplify
complex calculations Ð and that in turn led to
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IL NUOVO SAGGIATORE
32
new physics. In the past century, Feynman's
new way of thinking about quantum field theory
transformed the way that physics felt in our
heads.
In this course of the International Summer
School, ``Enrico Fermi'', we explore the issues of
how people think about physics, how they learn
physics, and how we can optimize what we can
do to help them. As physicists, we know that
when we study an interaction, it is not a good
idea to restrict our study to one end of the interaction. As we begin to think about physics as
an interaction between the world outside our
heads and the world inside our heads, it becomes of great value to begin to pay explicit
attention to the oft neglected end Ð how people
think about physics.
In addition to the intellectual challenge of
understanding our physics on a new, deeper level, these activities have powerful implications
for teaching and there are critical questions to
be studied and answered. In this course we
discuss (at least) three distinct populations of
physics learners: physicists to be, scientists and
engineers in other professions, and the general
populace.
For our intellectual descendents, the physicists-to-be, we recall our own struggles. Often,
it took us years to see the coherence and simplicity in a topic of physics. Is it possible to
shorten the path? The amount of physics we
need to learn to do forefront research continues
to grow. We need to develop new efficiencies.
Some results from physics education research
indicate that new methods of teaching, better
``impedance matched'' to the state of the learner, can help first year students do as well on
conceptual issues as physics graduate students.
Transformations are needed at all levels and
these must rely heavily on understanding what
are the elements of deep understanding in
physics.
For our colleagues in other sciences and engineering, physics is becoming an increasingly
important foundation as technology provides
increasingly powerful tools of observation and
control. Yet in fields such as biology and computer science, what their students need to know
for their own professions has grown dramatically and has begun to squeeze all non-essential
elements out of their own curricula. What does
physics have that is essential for these students,
and how can we provide it to them in the small
amount of time they have to study physics?
For the general populace, they have to live in
an increasingly technical environment. In the
great democracies of the world, members of the
general population not trained directly in science are called on to make decisions that may
rely heavily on scientific information. How
much does a judge, a member of parliament, a
voter need to know about science?
For all these questions it is clear that the answers are not simple. There is not a list of facts a
physicist or a member of parliament should
know; rather, there is a way of thinking about
the world and how we describe it that they need
to develop. In this course, we consider a wide
range of these issues from a variety of viewpoints. Physics education research, like many
other young fields of physics, has a variety of
viewpoints and a variety of goals. This course
has been designed to give an overview of some
of these viewpoints and to provide a benchmark
for further development.
Let me conclude by thanking the Italian Physical Society for choosing Physics Education
Research as a topic for a Varenna school and for
honoring us with their celebratory symposium.
IL NOSTRO MONDO
CERIMONIA A GROSSETO PER ORESTE
PICCIONI
Lo scorso 12 aprile, la Maremma Grossetana
ha tributato l'estremo saluto al piuÁ illustre dei
suoi figli, lo scienziato Oreste Piccioni, le cui
ceneri sono giunte dalla California a un anno
dalla Sua scomparsa, cosõÁ come lo stesso
scienziato aveva chiesto che avvenisse per riposare nella tomba della mamma, nella Sua
terra. La cerimonia si eÁ svolta a cura dell'associazione onlus ``Amici di Etruria Nuova''
(periodico fondato il 10 marzo 1893 da Giuseppe
Benci, mazziniano e noto massone di Palazzo
Giustiniani), della Provincia e del Comune di
Grosseto, sotto l'alto patronato del Presidente
della Repubblica, Carlo Azeglio Ciampi, e con il
patrocinio di: Regione Toscana, Accademia
Nazionale delle Scienze detta dei XL, E.N.E.A.,
Istituto Tecnico di Via Panisperna di Roma,
Scuola Normale Superiore di Pisa, SocietaÁ Italiana di Fisica e SocietaÁ Italiana per il Progresso
delle Scienze. Il Ministero dell'Interno, su proposta del Prefetto e del Questore, ha anticipato
di un giorno la locale Festa Nazionale della Polizia di Stato. Tra i messaggi pervenuti, quelli del
Presidente della Repubblica e del Console degli
Stati Uniti a Firenze.
La cerimonia si eÁ svolta nel Teatro Comunale
degli Industri, alla presenza di tutte le autoritaÁ di
Stato e locali, delle rappresentanze dei Comuni
e della Provincia giunte con i gonfaloni, oltre
che della Regione Toscana.
Prima della cerimonia i famigliari di Oreste
Piccioni, giunti appositamente dagli Stati Uniti,
erano stati ufficialmente ricevuti nella sala del
Consiglio Comunale dal Sindaco, dal Presidente
della Provincia e dalle altre autoritaÁ; anch'essi
hanno seguito le fasi della manifestazione commossi. Numerosa l'affluenza di cittadini e studenti. I famigliari sono stati ospiti dell'Amministrazione Comunale di Castiglione della Pescaia, di quella di Magliano in Toscana e dell'altra
di Monte Argentario. Il Sindaco di Castiglione,
Monica Faenzi, ha reso noto, tra l'altro di aver
deciso di dedicare una strada a nome di Oreste
Piccioni. I famigliari di Oreste sono rimasti
entusiati dell'ambiente naturale maremmano
ovunque osservato, trovandovi conferma delle
innumerevoli descrizioni loro fatte dal genitore,
nonche dei preziosi contenuti di immenso valore
storico ed artistico del Museo Etrusco di Vetulonia. Descrizioni spesso accompagnate dai
racconti di tristi avvenimenti dell'epoca di
guerra quando il loro genitore fu catturato dai
nazisti dai quali riuscõÁ miracolosamente a fuggire.
La figura e l'opera di Oreste Picioni sono state
illustrate dal direttore responsabile di ``Etruria
Nuova'', il giornalista Gino Bernardini, autore
della presente cronaca, che ebbe lo scienziato
tra gli amici adulti della sua infanzia. Ha ricordato la bontaÁ d'animo di Piccioni, la Sua vicinanza verso tutti i piuÁ giovani amici, la Sua
passione per il gioco del calcio lungo le strade
Saffi e Colombo, le sassaiole sulle Mura Medicee, la raccolta dei capperi dai cespugli nati
nelle crepe dei bastioni. Ha dato lettura, poi, di
un biglietto scritto dallo Scienziato ad un vecchio amico, Morgaro Morgantini, nella primavera del 2001, nel quale, tra l'altro, si legge:
``FaroÁ il possibile per tornare presto in Maremma. Grosseto eÁ cambiata, le automobili sono
troppe. I cavalli troppo pochi. Ma eÁ sempre la
nostra. Le Mura, dove si facevano le sassaiole,
sono sempre belle''.
Ha citato, inoltre, la miseria che tormentava il
grande fisico, orfano della guerra 15/18, rimasto
con la mamma, sarta da uomo, e la sorella Anna di
un anno piuÁ grande di lui. Poi ha fatto cenno alle
simpatie politiche di Piccioni, molto vicino al
Partito d'Azione, del quale giaÁ nel periodo clan-
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IL NUOVO SAGGIATORE
34
destino, la sorella era attiva militante e, nell'immediato dopoguerra, fu tra le fondatrici dell'Unione Donne Italiane, a Grosseto ed altrove,
insieme alle compagne dei partiti Comunista e
Socialista. Militanza che il Presidente della Repubblica, evidentemente, non ha dimenticato
quando ha rivolto il proprio saluto anche ad Anna
(in quei giorni insignita della onorificenza di Cavaliere al Merito della Repubblica Italiana) nel
messaggio letto da Bernardini.
Il Vice Presidente della Giunta Toscana, Angelo Passaleva, ha poi espresso il saluto del
Presidente della Regione Claudio Martini, seguito dal Presidente dell'Amministrazione Provinciale, Lio Scheggi, e dal Sindaco della CittaÁ,
Alessandro Antichi. Ad essi hanno fatto seguito
le relazioni degli scenziati Franco Bassani, Presidente della SocietaÁ Italiana di Fisica, e Giorgio
Salvini, Presidente Onorario dell'Accademia dei
Lincei.
Il Professor Bassani ha illustrato gli inizi
dell'attivitaÁ scientifica di Oreste Piccioni prima
della Sua partenza per gli Stati Uniti, mostrando i temi da Lui svolti nel 1934 per il
IL NOSTRO MONDO
concorso di ammissione alla Scuola Normale
Superiore di Pisa ed i suoi primi lavori, pubblicati su ``Il Nuovo Cimento'' della SocietaÁ
Italiana di Fisica, dal 1942 al 1947, culminati
nella scoperta che ha consentito di chiarire la
natura dei mesoni mediante il famoso esperimento di Conversi, Pancini e Piccioni. Lo
scienziato ha testimoniato poi dei legami costanti avuti dallo stesso Piccioni con i fisici
italiani e con la SocietaÁ Italiana di Fisica,
proiettando documenti ed immagini relativi
alla sua partecipazione al convegno di Bologna
del 1984, per il cinquantenario della scoperta
delle interazioni deboli di Fermi. Come ultimo
regalo alla Fisica Italiana, ha concluso Bassani,
Oreste Piccioni accettoÁ con entusiasmo di
iscriversi alla SocietaÁ nel 2000, poco prima
della sua scomparsa.
Il Professor Giorgio Salvini, anch'egli allievo
della Scuola di Roma e amico personale di
Oreste Piccioni, ne ha illustrato la figura di
uomo e di scienziato, svolgendo anche una
disamina dei principali risultati ottenuti dallo
Scomparso nel suo lungo percorso scientifico,
prima a Roma e, dopo il 1946, negli States, al
M.I.T. di Boston, ai laboratori di Brookhaven e
dal 1960, all'UniversitaÁ di California, San Diego. La descrizione, fluida ed appassionata, eÁ
stata seguita con attenzione e con vivo interesse anche dal folto uditorio che non ha
competenze specifiche in fisica moderna. E'
stata la preparazione ad una piuÁ tecnica esposizione che avraÁ luogo all'Accademia dei Lincei
il 12 novembre.
Salvini ha descritto poi in dettaglio il primo
esperimento, che aprõÁ la strada alla fisica dei
leptoni (particelle leggere) e alla conoscenza
odierna del mondo subnucleare, lo sviluppo di
nuove tecniche di estrazione del fascio di particelle e di lenti magnetiche che consentono di
separare quelle di carica diversa, che vennero
usate da Emilio SegreÁ e collaboratori per la
scoperta dell'antiprotone (Nobel 1959). Immediatamente dopo la scoperta dell'antiprotone
Oreste Piccioni scoprõÁ, nel 1956, l'antineutrone.
Salvini descrive anche i risultati degli interessi
piuÁ squisitamente teorici di Oreste Piccioni, in
particolare la teoria della rigenerazione di particelle che sono stati quantici misti, sviluppata
con Abraham Pais, e i suoi studi sul paradosso di
Einstein, Podorski e Rosen della meccanica
quantistica. L'esposizione eÁ stata arricchita con
la proiezione di documenti e lettere personali di
grande interesse.
EÁ seguito il ricordo di Oreste Piccioni da
parte di uno degli amici di liceo dello scomparso, il Dottor Fernando Giusti (presenti anche i Dottori Raffaello Cambi, Lelio Marini ed
altri), ex liceali che ben ricordano ancora
quando il loro docente di fisica e matematica,
Professor Nencini, affidoÁ ad Oreste un biglietto
per Enrico Fermi, nel quale tra l'altro gli
scrisse questa preveggente nota: ``Caro Enrico,
ti mando un piccioncino che ha giaÁ messo le ali
e che, ne sono sicuro, voleraÁ molto lontano''.
Infine, Cristopher, uno dei cinque figli di Oreste, a nome di tutti i famigliari, ha concluso la
cerimonia esprimendo con viva commozione
parole di gratitudine per l'avvenimento.
La cittaÁ di Grosseto ha dedicato al nome di
Oreste Piccioni un intero comparto viario, nella
zona di espansione urbanistica sita a nord ovest
dell'abitato.
35
Terminata la cerimonia, un corteo ha raggiunto la vicina Via Colombo dove, al numero
51, eÁ stata inaugurata una lapide al ricordo
della prima residenza e del primo laboratorio
nei quali lo scienziato abitoÁ e lavoroÁ, dopo
essersi laureato nel 1938 a Roma, dove Piccioni si era trasferito per seguire Enrico Fermi,
lo stesso anno della scomparsa della mamma,
Calliope Burali. Un picchetto d'onore dell'Arma dei Carabinieri ha prestato servizio in
alta uniforme e le note del silenzio fuori ordinanza (perfettamente eseguito da un sottoufficiale dell'Arma) hanno toccato visibilmente
tutti i presenti.
Gino Bernardini