# Wolfgang Pauli
## (1900 - 1958)
Pauli was born in Vienna, Austria on August 25, 1900.
Pauli attended the Döblinger Gymnasium in Vienna, graduating with
distinction in 1918. Only two months after graduation, he published
his first paper, on Einstein's theory of general relativity.
He attended the Ludwig-Maximilian University of Munich,
where he received his doctorate in July 1921 for a thesis on the quantum
theory of ionised molecular hydrogen. During his time at the University
of Munich, Pauli was requested to review relativity for the *Encyklopaedie
der mathematischen Wissenschaften*, a German encyclopedia. It was
praised by Einstein;
published as a monograph, it remains a standard reference on the subject
to this day.
He spent a year at the University of Göttingen
as the assistant to Max
Born (Nobel
Prize recipient in 1954), and the
following year at what became the Niels Bohr Institute for Theoretical
Physics in Copenhagen. From 1923 to 1928, he was a lecturer at the University
of Hamburg. During this period, Pauli was instrumental in the development
of the modern theory of quantum mechanics. In particular, he formulated
the exclusion principle and the theory of nonrelativistic spin.
In 1928, he was appointed Professor of Theoretical
Physics at the Federal Institute of Technology in Zurich, Switzerland.
He held visiting professorships at the University of Michigan in 1931,
and the Institute for Advanced Study at Princeton in 1935.
The German annexation of Austria in 1938 made Pauli a German citizen, which became a difficulty with the outbreak
of the Second World War in 1939. Pauli
moved to the United States in 1940,
where he was Professor of Theoretical Physics at Princeton. After the
war, Pauli became a naturalized citizen of the United States in 1946
before returning to Zurich, where he remained for the rest of his life.
In 1945, Pauli received the Nobel
Prize in Physics for his "decisive contribution through his
discovery in 1925 of a new law of Nature, the exclusion principle or
Pauli principle." He had been nominated for the prize by Einstein.
In 1958, Pauli was awarded the Max Planck medal. In
that same year, he fell ill with pancreatic cancer. Pauli died on December
15, 1958.
### Scientific Career
Pauli made many important contributions in his career
as a physicist, primarily in the subject of quantum mechanics. He seldom
published papers, preferring lengthy correspondences with colleagues
(such as Bohr and Heisenberg, with whom he had close friendships.) Many
of his ideas and results were never published and appeared only in his
letters, which were often copied and circulated by their recipients.
Pauli was apparently unconcerned that much of his work thus went uncredited.
The following are the most important results for which he has been credited:
In 1924, Pauli proposed a new quantum degree of freedom
to resolve inconsistencies between observed molecular spectra and the
developing theory of quantum mechanics. He formulated the Pauli exclusion
principle, perhaps his most important work, which stated that no two
electrons could exist in the same quantum state. Uhlenbeck and Goudsmit
later identified this degree of freedom as electron spin.
In 1926, shortly after Heisenberg published the matrix
theory of modern quantum mechanics, Pauli used it to derive the observed
spectrum of the hydrogen atom. This result was important in securing
credibility for Heisenberg's theory.
In 1927, he introduced the Pauli matrices as a basis
of spin operators, thus solving the nonrelativistic theory of spin.
This work influenced Dirac in his discovery of the Dirac equation for
the relativistic electron.
In 1930, he proposed the existence of a hitherto unobserved
neutral and massless particle, in order to explain the continuous spectrum
of beta decay. In 1934, Fermi incorporated the particle, which he called
a neutrino, into his theory of radioactive decay. The neutrino was first
observed experimentally in 1959.
In 1940, he proved the spin-statistics theorem, a
critical result of quantum mechanics which states that particles with
half-integer spin are fermions, while particles with integer spin are
bosons.
**Sources:** Wikipedia.
Picture courtesy of: Fermi
National Accelerator Laboratory |