Wolfgang Paulis 100th birthday
A personal view by Prof. C. P. Enz, W. Paulis last
assistant |
According to a recent inquiry by Physics World concerning
the ten most important physicists ever, Wolfgang Pauli does
not belong to them.
For those of an older generation for
whom Pauli was the conscience of physics this
comes as a surprise.
But it shows perhaps that both his exclusion
principle and his neutrino idea which at first were
hard to swallow have since become household words,
while his proverbial wit is lost to a generation communicating
by e-mail.
So who was this man?
Pauli was born just 100 years ago
on 25 April 1900 in Vienna.
His
father Wolf Pascheles came from a well-known Jewish family
in Prague where he studied medicine with one of Ernst Machs
sons and took physics classes from Mach himself.
As a young medical doctor Wolf
Pascheles settled in Vienna in 1893, took the name of Pauli,
was baptized Catholic and married in 1899.
Mach, who accepted
a chair of philosophy at the University of Vienna in 1895
accepted to be godfather for Paulis son Wolfgang.
At age 13 Wolfgang read Machs famous Mechanics that
the latter had given him with a dedication.
At 18, before
becoming a student of Arnold Sommerfeld in Munich, Pauli
published his first paper on general relativity.
Sommerfeld,
who saw that this young man could not learn much more from
him, let Pauli write a review on relativity in the Encyklopdie
der Mathematischen Wissenchaften.
This almost perfect work
published in 1921 (still a standard reference today) made
Pauli famous.
Paulis biting wit was already well-known.
When in 1922 Paul Ehrenfest who had also written
an Encyklopdie article met Pauli, he said to
him :
Pauli, I like your Encyklopdie article
better than yourself, to which Pauli answered : How
strange, with me it is just the opposite!.
In Copenhagen
where Pauli spent the year 1922/23 at Bohrs institute
he became a good friend of Bohrs assistant Hans Kramers
who remarked : Pauli, your heart is better than your
wit!.
The following six years Pauli spent in Hamburg where three
fundamental ideas were born.
First, Pauli introduced the
fourth quantum number of the electron that later was recognized
as the spin.
Then, making use of this fourth quantum number,
he formulated the exculsion principle which could explain
the periodic system of the elements and later was recognized
to be responsible, quite generally, for the stability of
matter.
But even before that he had postulated the existence
of a nuclear spin in order to explain the hyperfine anomalies
in the spectra.
Hamburg also was the scene of Paulis
discussions with Otto Stern.
But in spite of this friendship
Stern would not let Pauli enter his laboratory because
of the Pauli effect.
For, it was said that every time Pauli
entered a laboratory something went wrong.
Pauli believed
in it and was amused.
In 1928 Pauli became the successor of Peter Debye at ETH,
the Swiss Federal Institute of Technology in Zurich.
He asked
for only one condition, namely to have a research assistant.
Pauli stayed in this position to the end of his life, and
at the same time the assistantship was occupied 12 times.
The first of Paulis assistants was Ralf Kronig.
With
him and with his experimental colleague Paul Scherrer, Pauli
explored the night life of Zurich.
The second assistant,
Felix Bloch, later received the Nobel Prize.
Of the third,
Rudolf Peierls from Berlin, Pauli said : Peierls,
he speaks so fast, when one understands what he has said
he already claims the contrary.
Hendrik Casimir, the
fourth assistant, later became a director with Philips at
Eindhoven.
When Pauli then heard that one was going to Holland
he would say : when you see Casimir, call him Herr
Director, for, that vexes him!.
His fifth assistant,
Victor Weisskopf had the misfortune to publish the result
for the self-energy of the electron with the wrong sign,
whereupon Pauli mused : I should have taken Bethe! For,
Hans Bethe was an accomplished calculator, but he worked
on the solid state which displeased Pauli.
Apparently, later
assistants came away with milder jugements until
the last, myself, who at the beginning ignored that organizing
tickets for classical concerts for Pauli and collaborators
was one of the assistants tasks.
One day I had in
my mail a card from a bar in down-town Zurich, on which Pauli
complained that he had missed a concert with Isaac Stern
and which closed with the hope of better times.
There was also a more hidden side to Paulis personality.
At the beginning of his professorship at ETH he developed
a neurosis which manifested itself in the fact that, as he
told his friend and colleague at the University of Zurich,
Gregor Wentzel, with the women things dont
go at all.
In fact, a first marriage failed after
less than a year. It was during this period, however, that
Pauli had the idea of the neutrino as the only way out of
the problem of an energy deficit in the beta-decay.
In
1932 Pauli met the famous psychiatrist Carl Gustav Jung in
Zurich which resulted in a psychoanalysis during three years.
Shortly afterwards Pauli remarried, this time durably.
Jung
had immediatly seen that Pauli had frequent dreams containing
a wealth of archaic material that caught Jungs keen
interest.
From this time on Pauli wrote up his dreams, and
a fascinating exchange of ideas developed between Pauli and
Jung which lasted almost to the end of Paulis life.
The war years, from 1940 to 1946 Pauli spent in the United
States at the Institute for Advanced Study in Princeton.
There he published the famous spin-statistics theorem which
probably constitutes his most brilliant paper.
It was in
Princeton that in November 1945 the news of his Nobel Prize
for the exclusion principle reached him.
But Pauli went to
Stockholm only in 1946, on the way back to ETH in Zurich.
Instead there was a great celebration in Princeton where
Einstein unexpectedly rose for a toast, in which he designated
Pauli his spiritual son and successor at the Insitute for
Advanced Study.
Back in Zurich Paulis institute became a world centre
of quantum field theory. Moreover Pauli, influenced by his
dreams, also devoted much time to the archetypal background
of physical ideas.
This he first exemplified with Johannes
Kepler, on whom he wrote an important essay, and went on
to physical notions in general.
In the mid-fifties, again
guided by dreams, he turned his attention to symmetries and
wrote the important paper on the CPT-theorem This was like
a presentiment of the sensational news in January 1957 of
parity violation in weak decays.
The last year of his life
Pauli let himself be carried away by the world formula,
a non-linear Dirac equation, of his life-long friend Werner
Heisenberg who had succeded in building into it an internal
symmetry.
But realizing the shortcomings of this approach,
Pauli soon withdrew again in disappointment.
And after a
short struggle with cancer he died in Zurich on 15 December
1958.
Source : http://www.europhysicsnews.com/full/04/article5/article5.html |