The
diversity of scientific opportunities that now exists at Columbia has grown out of a long and
distinguished tradition of physics teaching and research. Columbia graduates, along with many other
scientists who spent their formative years here, have gone on to make
extraordinary contributions to science as researchers, teachers, and
intellectual leaders. The array of Nobel prizes acknowledges singular accomplishments that are widely recognized
by their colleagues and the lay community. Such awards typically represent only the most visible points in a research
program. A Nobel prize list only hints
at the wide diversity of accomplishment underpinning forefront physics research
done by Columbia
students and faculty over the decades. Large
numbers of Columbia
graduates, along with many other scientists who spent their formative years
here, have gone on to make extraordinary contributions to science in research,
as teachers, and as intellectual leaders.
A
CENTURY AGO
The graduate department was formally
established in 1892, although the roots of graduate physics can be traced to
the opening of the School
of Mines in 1864. The first physics PhD, Robert Millikan, went on to win a Nobel Prize. The
central figure in the early years of the Department was Michael Pupin, who contributed
substantially to new discoveries involving X-rays and to the continued
understanding and applications of electromagnetism. He served as Department
Chair for many years. Under his
impressive leadership, the present Pupin Laboratory was completed in 1925 to
serve as the home of the Physics Department. After his death in 1935, the building was named for him.The
Department still resides here.
In
May 1899, the American Physical Society was founded at Columbia. The Earnest Kempton Adams (EKA)
Fund was established in 1904, enabling the department of Physics to invite
distinguished scientists to Morningside. H.A. Lorentz was appointed EKA
Lecturer in 1905-1906 and Max
Planck in 1909. One of Lorentz’ most important works, The
Theory of Electrons, was written during his tenure at Columbia.
In
the early years of the twentieth century, Lorentz’ work had led toEinstein's
theory of relativity, and Planck's black-body radiation formula led Einstein to
the concept of the quantum, which culminated in the theory of quantum
mechanics, developed by Bohr, Schroedinger, Heisenberg and many others in
Europe over the two decades from 1910-1930. These ideas underlie our present understanding of nature at its most fundamental
level, and represent great historical intellectual achievements. Most modern scientific and technological
developments--nuclear energy, atomic physics, molecular beams, lasers, x-ray
technology, semiconductors, superconductors, supercomputers-- were realized
only because we could build on the foundations of relativity and quantum
mechanics. The Columbia Physics
Department played significant roles in several of these and related
developments over ensuing decades.
I.I.
Rabi, a Columbia graduate student in the 1920’s,
was very interested in the new Quantum Mechanics being developed primarily in Europe. After
completing his degree, he received a fellowship to spend a few years in
European laboratories. On his return to Columbia, he spearheaded successful efforts to put Columbia, and the U.S., at the forefront of scientific research.
By
1931, Columbia
had become a visible science presence with Harold Urey’s discovery of deuterium
(Nobel Laureate in Chemistry, 1936) using a new spectrometer in Pupin Laboratory. That reputation continued as Rabi did his
famous work with atomic beams and George Pegram investigated phenomena
associated with the newly discovered neutron. In the fall of 1938, Italian
fascism had created a hostile environment for Enrico Fermi, so he decided to
leave his native country. His Nobel Prize award that year gave him the perfect
opportunity to visit elsewhere. He wrote to George Pegram regarding this
possibility, and received every encouragement to come to Columbia.
The
war years saw great activity at Columbia and by Columbia faculty.Soon after Fermi arrived, he set about
verifying the fission properties of the Uranium isotopes and pursuing what
later became the Manhattan Project
to develop the first nuclear weapon. Rabi, as wartime Director of Research of the
Radiation laboratory located at MIT, worked on the development of radar.
MID 20th
CENTURY - ATOMIC AND NUCLEAR PHYSICS
I.I.
Rabi's contributions to the development of atomic and molecular physics and
some of the basic discoveries in nuclear fission by Enrico Fermi and his
collaborators ushered in a golden era of fundamental research. This period just prior to World War II was
marked particularly by Rabi’s measurements of the spins and magnetic moments of
atoms and nuclei, by the construction of the “Pupin cyclotron” by Dunning, and
by the work of Fermi, Dunning and others on nuclear fission. After the war, many experiments were
groundbreaking, particularly those by Polykarp Kusch and Henry Foley on the
magnetic moment of the electron and Willis Lamb's work on the fine structure of
hydrogen. These were crucial to the
development of quantum electrodynamics. Theoretical research in the 1940s
involved close collaboration with the atomic physics experiments. Goals emphasized calculations to clarify
precise predictions of quantum electrodynamics to compare with experiment.
Microwave
techniques developed by Columbia
faculty members during the war were later used to explore molecular spectra;
the observation of large nuclear quadrupole moments stimulated the unified
nuclear model of James Rainwater and Aage Bohr. Molecular spectroscopy also led Charles Townes and his collaborators to
the development of the maser, the microwave precursor of the laser. These works were recognized by the Nobel
Foundation.
High
energy physics and properties of subatomic particles increasingly became a
major postwar focus. In 1950, Columbia's
cyclotron was commissioned at Nevis Laboratories in Westchester
County about twenty miles north of Morningside. The Nevis Laboratories continue
to house substantial infrastructure in support of experimental programs in the
department.T. D. Lee, his collaborators, and their students made major
strides in understanding the symmetries of subatomic particles, culminating in
the prediction of parity violation in the weak interactions. The effect of maximal parity nonconservation was quickly observed in the landmark nuclear physics experiment conducted in Pupin by C.S.
Wu.Soon afterwards, maximal parity
violation was also found in pion- and muon- decay experiments by Leon Lederman
and Richard Garwin at Nevis.
Life as a graduate student in the 1950’s was both interesting and
exciting.
HIGH ENERGY AND NUCLEAR
PHYSICS
The
desire to investigate matter on an increasingly fine scale led to experiments
using beams of increasingly high energies. Beginning in the 1950’s, the Nevis cyclotron and accelerators at Brookhaven National
Laboratory were used in a number of experiments that continued beyond the
decade. The structure of nuclei was
delineated by observing X-ray transitions in muonic atoms; observations of pion
and muon decay constituted further validation of maximal parity
nonconservation; and in 1964, Lederman, Mel Schwartz, and Jack Steinberger
proved that the muon neutrino was distinct from the electron neutrino.
By
the early 1970s, particle physicists began using even higher energy accelerator
beams, and Columbia experimenters spread out to
accelerators in Europe and the new Fermi National Accelerator Laboratory (FNAL)
west of Chicago. By mid-decade, the Standard Model of
elementary particles was becoming established, with electroweak interactions
and quantum chromodynamics (QCD) describing the basic forces and constituents
of matter. It ultimately incorporated
three families of leptons (electron-like) and three families of quarks
(proton-like) as the observed constituents, with two members in each family. The second quark family, with one already
well-established (“strange”) member was then confirmed to have a second member:
the “charm” quark.In 1977, Lederman led
an effort at FNAL which discovered the first member (“bottom” quark) of the
third quark family. (The remaining very
massive “top quark” was confirmed in 1995 by experiments performed at Fermilab;
collaborators from Columbia participated in this discovery.)
During
the ensuing two decades, experiments at FNAL with neutrino beams, led by Columbia experimenters,
verified electroweak predictions of the Standard Model, and definitively
established the quark and gluon constituency of nucleons assumed in QCD. Furthermore, these and other experiments
demonstrated QCD as the best predictor of measurable strong interaction
phenomena. Beginning in 1985, Columbia physicists led
experiments using the accelerator complex at the German DESY laboratory, where
predictions of the Standard Model were further verified while searching for
specific effects beyond the Model. Properties of nucleon structure and QCD, the force holding quarks within
the proton were investigated in many different ways and in phenomena that QCD
did not easily predict. In the process,
the proton was found to contain huge numbers of gluons carrying very tiny
fractions of the proton momentum as expected in the developed QCD theory; where
such gluons carry the strong interaction force.
Many
studies of the second quark family’s charm quark were carried out in the period
between 1985 and 1995 by Columbia
physicists at the Cornell accelerator. These measured specific properties of charm, and properties of the
binding of charmed quarks inside nucleons. Additional studies of important properties of the bottom quark were led
by Columbia
physicists using the Stanford SLC accelerator during the same period. This program also provided important
information on the properties of the elementary bosons that carry the
electroweak forces.
Substantial
theoretical work on QCD continues to be carried out by Columbia theorists, with many difficulties to
be overcome in making predictions from such a highly nonlinear theory. Since 1981, Columbia theoreticians have led in designing,
constructing, and utilizing novel parallel processing computing systems to
carry out these calculations. The
details of many strong interaction phenomena, including the binding properties
and masses of specific meson and baryon states, could begin to be predicted
with accuracy.
By
1990, Columbia-led experiments were exploring implications of QCD in collisions
of heavy nuclei at higher and higher energies. In collaboration with Brookhaven National Laboratory, the Relativistic
Heavy Ion Collider (RHIC), constructed to accelerate and collide heavy nuclei,
is advancing our understanding of nuclei and explores new forms of nuclear
matter, including the quark-gluon plasma. This program continues today.
Columbia scientists
will be playing an important role in major experiments at the soon-to-be
completed LHC super-high energy collider in Switzerland. Among other exciting possibilities, these may
at last reveal the origin of the masses of the familiar elementary particles of
our Universe. Columbia physicists are also continuing to
play important leadership roles using neutrinos to understand their intrinsic
nature, including their masses and interactions with each other.
ASTROPHYSICS
Astrophysics
had its roots in early collaborations between astronomers and physicists at Columbia. In 1967 the Columbia Astrophysics Laboratory
(CAL) was founded and, under the leadership of Columbia physicist Robert Novick, this fledgling
organizationquickly moved to the
frontier of high energy astrophysics. By
the early 1970's, CAL
was, along with MIT, Harvard, and the NASA Goddard Space Flight Center, the
architect of a series of three satellites that would make X-ray observations a
central feature of our study of the Universe. Today the astrophysics lab boasts
23 faculty, 37 other PhD scientists and 40 graduate students from three
departments.
In addition to studies of extraterrestrial
X-rays, areas of research in the department have included measurements of the
very highest energy cosmic rays; design, construction, and operation of innovative
instruments to find the thus far undiscovered dark matter; measurement of the
radiation from the Big Bang, detection and studies of neutron stars and black
holes; and charting the star formation history of the Universe. Throughout the
entire period, such experimental and observational efforts have always complementedforefront theoretical
and phenomenological research.
ATOMIC AND CONDENSED MATTER
PHYSICS
Columbia had, from the postwar period onwards, been involved in the study
of complex material and electromagnetic systems, both from theoretical and
experimental perspectives. The Columbia
Radiation Lab gave such programs a home and work on laser phenomena has
continued in the Department since the invention of the maser here by Townes and
Schwalow. Experimental condensed matter
physics had a rebirth in the department in the late 1980’s with the
establishment ofprograms studying spin
glasses and high temperature superconducting systems with muons and
neutrons. The program grew with new people
and efforts, both from joint programs with other departments and with new
individuals who joined the department. One new appointment, Horst Stormer, received the Nobel Prize soon after
coming to Columbia
for his discovery of the fractional quantum hall effect. More recently, interdisciplinary
collaboration between physics, chemistry and the engineering school has given Columbia a leadership role
in the burgeoning field of nanoscience.
CONCLUSION
Although
some of today’s questions and the tools used to answer them were inconceivable
50 years ago, one aspect of life in Pupin has not changed: Science at Columbia continues to be
done by people who care deeply and passionately for the truth.
More
detailed descriptions of current experimental and theoretical efforts can be
found at the department’s research web page.
