A childhood on the road
Roy Jay Glauber was born in New York City on September 1, 1925, to Emanuel Glauber and Felicia Fox Glauber. His father was a travelling salesman, and when Roy was two the family took to the road so that his father could cover customers across the American Midwest. In his Nobel autobiography Glauber remembered nights spent in farmhouses that had hung out a “Tourists-Vacancy” sign, rooms lit by kerosene and acetylene lamps, and his mother, a trained elementary school teacher, turning every small town into a lesson: she took him to fire stations, courtrooms and police departments so that the boy would learn how a community worked.
The 1929 crash cost his father his job and the company car, and the birth of a daughter in 1931 meant the family had to settle down. They moved first into a crowded flat in upper Manhattan with his father’s mother and aunt, then to Sunnyside in Queens, then to the Bronx and back to northern Manhattan, following the rent bargains of the Depression. Money was tight. Glauber built model aircraft from kits that uncles and aunts gave him, and an uncle bought him a subscription to Popular Mechanics, which, he admitted, inspired many projects he never managed to finish.
A boy who built telescopes
Astronomy caught him early. After a visit to the Hayden Planetarium with his aunt, he set out at the age of twelve to build a reflecting telescope, spending nine months grinding and polishing the mirror by hand. The steel axis of the mount came from the steering shaft of a Ford found in a junkyard; a local smith heated and bent it to the latitude of New York and charged him 25 cents. He spent less than five dollars on the whole instrument and observed from the roof of his apartment building. A planetarium lecturer, Dorothy Bennett, heard him describe his plans at a youth science congress in 1937 and invited him into the Junior Astronomy Club; he later called her “an influence in my life.”
In 1938 he entered the newly founded Bronx High School of Science and graduated with its first class in 1941. A mathematics teacher suggested he teach himself calculus from a textbook, and he did. He also built a spectroscope with a diffraction grating lent by the principal; it won two prizes and was displayed at the 1939 New York World’s Fair. With the help of a Harvard Club scholarship he entered Harvard College in the autumn of 1941, aged sixteen, and by eighteen he had taken most of the university’s graduate physics courses.
The youngest theorist at Los Alamos
In October 1943 a recruiter visited Harvard and invited Glauber to join an unnamed project “out west.” It was Los Alamos, the laboratory of the Manhattan Project, and at eighteen he was one of its youngest scientists. Working in Hans Bethe’s theoretical division, he calculated the diffusion of neutrons, part of the problem of finding the critical mass of the bomb. He recalled feeling, as everyone around him did, that the Germans might be building the same weapon. In July 1945 he watched the flash of the Trinity test from Sandia Peak, more than a hundred miles away, and he became one of the last surviving witnesses of that first nuclear explosion.
The experience stayed with him. Later in life he served on the national advisory board of the Center for Arms Control and Non-Proliferation, and at a meeting of Nobel laureates in 2016, asked how far nuclear arsenals should be reduced, he answered that absolute zero was the only figure that made sense.
From Princeton to Harvard
Glauber returned to Harvard, finished his bachelor’s degree in 1946 and earned his PhD in 1949 under the nominal supervision of Julian Schwinger, though by his own account he worked largely on his own. Robert Oppenheimer then invited him to the Institute for Advanced Study in Princeton, and in 1950 he spent several months in Zurich with Wolfgang Pauli. In 1951 to 1952 he taught at the California Institute of Technology, filling in for Richard Feynman, who was spending a year in Brazil.
At Caltech a puzzle from Linus Pauling’s chemists about electron diffraction led him to a general theory of how fast particles scatter from complex targets. Back at Harvard from 1952, he developed it into what physicists still call Glauber theory, a way of treating high-energy collisions with nuclei as a kind of diffraction. In his Nobel autobiography he noted that it is used to analyse collisions between heavy nuclei at today’s accelerators. In 1963 he also published the first study of the time evolution of the Ising model, known as Glauber dynamics, a basic tool in statistical physics and computer simulation. He became a full professor in 1962 and Mallinckrodt Professor of Physics in 1976.
What is laser light?
The work that made his name began in the late 1950s, when two problems arrived together. The laser had just been invented, and no one had a proper quantum description of its light. At the same time the British astronomers Robert Hanbury Brown and Richard Twiss had found that photons from an ordinary light source tend to arrive at detectors in clumps, an effect that seemed to defy explanation. Light had been treated as a classical wave for most practical purposes, even though Einstein had shown in 1905 that it comes in quanta.
In 1963 Glauber published a series of papers that applied the full machinery of quantum theory to light and to the way detectors register it. He showed how to describe the statistics of photons counted by one detector or by several detectors at once, and he defined the “coherent state,” the quantum description of the ideal light from a laser. His theory explained why photons from a lamp or a star bunch together while those in a perfect laser beam arrive independently, and it predicted kinds of light that no classical wave could produce. The Indian-American physicist E. C. George Sudarshan developed a closely related representation of light in the same year. Together these ideas gave birth to a new field. As the Nobel committee put it, no real in-depth theory of light based on quantum theory existed before Glauber established the foundation for quantum optics in 1963.
How it is used today
Quantum optics, the field Glauber founded, is now part of the infrastructure of modern technology. Every laser engineer who calculates the noise limit of an optical measurement uses concepts he defined, because the quantum “graininess” of light sets the final limit on how precise an optical instrument can be. The language of coherent states and photon correlations is the basis of single-photon sources and detectors, of quantum key distribution, which uses individual photons to send encryption keys that cannot be intercepted without detection, and of photonic approaches to quantum computing. Harvard’s memorial minute notes that his framework underlies experiments on quantum entanglement and teleportation and that gravitational-wave detectors now use “squeezed” quantum light to listen more sensitively to the universe.
Glauber himself kept working across the whole range of these questions: trapped ions, the statistics of atom beams, Bose-Einstein condensates and the nature of quantum jumps. He was also an adjunct professor of optical sciences at the University of Arizona, one of the great centres of optics in the United States. Colleagues remarked that his papers were written so clearly that they could be read as if they had been written yesterday.
Single father, Keeper of the Broom
In 1960 Glauber married Cynthia Rich, and they had a son, Jeffrey, in 1963 and a daughter, Valerie, in 1970. The marriage ended in the mid-1970s, and Glauber raised both children as a single father. He wrote that it cost him some papers he never got to write, and that he would not trade the experience for them or for any recognition. In later life he had five grandchildren.
He also had a playful side. For many years he took part in the Ig Nobel Prize ceremony at Harvard, the spoof awards for research that first makes people laugh and then makes them think, appearing as the “Keeper of the Broom” who swept the stage clear of the paper aeroplanes thrown by the audience. In 2005 he missed the ceremony for the first time: he was in Stockholm, receiving half of the real Nobel Prize in Physics “for his contribution to the quantum theory of optical coherence,” shared with John L. Hall and Theodor W. Hänsch, who were honoured for laser-based precision spectroscopy.
Jewish background
Glauber grew up in Depression-era New York, in a family of modest means that moved between Manhattan, Queens and the Bronx, and he was educated in the city’s free public schools, including the then new Bronx High School of Science. The Jewish Virtual Library counts him as a Jewish American physicist and includes him among Jewish Nobel laureates.
He wrote and spoke very little about religion. His own recollections dwell on family, teachers and public institutions: a mother who made learning out of every journey, uncles who supplied construction kits and a three-year magazine subscription, teachers who had come through the tuition-free city colleges, and a scholarship that made Harvard possible for a boy whose parents, he wrote, would never otherwise have imagined so large a leap.
Later years and legacy
Glauber received the Albert A. Michelson Medal and the Max Born Award in 1985, the Dannie Heineman Prize for Mathematical Physics in 1996, election to the National Academy of Sciences in 1988 and to the Royal Society as a foreign member in 1997. He kept teaching at Harvard into his eighties and lived for many years in Arlington, Massachusetts. He died in Newton, Massachusetts, on December 26, 2018, at the age of 93, and was buried at Kensico Cemetery in Valhalla, New York.
His legacy is a way of seeing light. Before 1963, physicists could describe a beam as a wave and a photon as a particle, but they had no consistent theory of what a light detector actually counts. Glauber supplied it, and in doing so he created a discipline that now trains thousands of researchers and underpins technologies from ultra-precise measurement to quantum communication. The boy who ground a telescope mirror in a Manhattan bedroom ended up explaining the nature of light itself.
Sources & further reading
Roy J. Glauber, Biographical, NobelPrize.org · The Nobel Prize in Physics 2005, Popular information, NobelPrize.org · Roy Jay Glauber, 93, Faculty of Arts and Sciences memorial minute, Harvard Gazette · Roy J. Glauber, Jewish Virtual Library · Roy J. Glauber, Wikipedia · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.