From Rymanów to the Lower East Side
Israel Isaac Rabi was born on July 29, 1898, in Rymanów, a small town in Galicia, then the Austrian-ruled corner of partitioned Poland. His parents were Orthodox Jews of modest means; his father worked as a tailor. In 1899 the family followed the great wave of Jewish emigration to America and moved into a two-room apartment on Manhattan’s Lower East Side, where the household spoke Yiddish. When his mother enrolled him in school she gave his name as “Izzy” and an official, assuming it was short for Isidor, wrote that down. The name stuck. Later, partly in response to antisemitism, he began signing himself Isidor Isaac Rabi, and the world came to know him as I. I. Rabi, though to friends and family he was simply “Rabi.”
In 1907 the family moved to Brownsville, Brooklyn, and opened a grocery store. Young Rabi devoured the children’s books in the public library and then moved on to the science shelves. He built his own radio set, and while still in elementary school published a short paper on the design of a radio condenser in the magazine Modern Electrics. Reading about Copernicus convinced him that the universe ran on laws, not on Providence, and he told his startled parents that he no longer believed in God. They reached a compromise for his bar mitzvah, held at home: the boy delivered his speech in Yiddish, on how an electric light works.
A long road to physics
After graduating from Brooklyn’s Manual Training High School in 1916, Rabi entered Cornell University to study electrical engineering, switched to chemistry, and graduated in 1919. It was a bad moment to be a young Jewish chemist: the chemical industry and most universities were largely closed to Jews, and no job offers came. He worked briefly at Lederle Laboratories and then as a bookkeeper, drifting for nearly three years.
In 1922 he went back to Cornell as a graduate student in chemistry and found himself drawn to physics. The next year he met Helen Newmark, a student at Hunter College, and to be near her he moved his studies to Columbia University in New York, supporting himself as a part-time tutor at City College. For his doctorate he measured the magnetic properties of crystals, inventing an elegant shortcut, inspired by reading James Clerk Maxwell, that suspended a crystal in a liquid whose magnetism could be tuned to match it. He mailed the thesis to Physical Review on July 16, 1926, and married Helen the following day.
An apprenticeship in Europe
Quantum mechanics was being born in Europe, and Rabi was determined to be there. A Barnard Fellowship in 1927 took him across the Atlantic, he resigned from City College when it refused him leave, and over two years he worked with or learned from nearly every great figure of the new physics: Arnold Sommerfeld in Munich, Niels Bohr in Copenhagen, Wolfgang Pauli and Otto Stern in Hamburg, Werner Heisenberg in Leipzig and Pauli again in Zurich. In Leipzig he met a fellow New Yorker, J. Robert Oppenheimer, beginning a friendship that would last for the rest of Oppenheimer’s life.
It was in Stern’s Hamburg laboratory that Rabi found his life’s subject. Stern’s group sent beams of atoms through magnetic fields to probe their properties, and Rabi devised a cleaner way to deflect them, using a uniform field and a glancing beam so the atoms bent like light through a prism. The result was published in Nature in 1929. In March of that year Columbia, on Heisenberg’s recommendation, offered him a lectureship, and he came home.
The resonance method
Rabi was, by the testimony of many students, a dreadful lecturer, but he was an inspired leader of research. In 1931, working with Gregory Breit, he derived the Breit–Rabi formula and showed how molecular beams could be used to read the properties of the atomic nucleus itself. With a growing band of young collaborators, Jerrold Zacharias, Sidney Millman, Polykarp Kusch, Jerome Kellogg and later Norman Ramsey and Julian Schwinger, he built Columbia’s Molecular Beam Laboratory, helped financially by Harold Urey, who gave Rabi half of his own Nobel Prize money.
The breakthrough came in 1937. Instead of simply deflecting the beam, Rabi’s team added an oscillating magnetic field. At one precise frequency, the nuclei absorbed energy and flipped their orientation, and the beam reaching the detector suddenly dipped. That frequency was a fingerprint of the nucleus’s magnetic moment, measurable with unprecedented accuracy. The team showed that the proton’s magnetic moment was about 2.79 nuclear magnetons, not the 1 that theory predicted, inferred the moment of the neutron, and discovered that the deuteron is not spherical, a vital clue to the nature of the nuclear force. For this “resonance method for recording the magnetic properties of atomic nuclei” Rabi received the 1944 Nobel Prize in Physics.
He was not without blind spots. Rabi did not believe women could be physicists, never took a woman as a doctoral or postdoctoral student, and generally opposed women as faculty candidates, an attitude his biographers record plainly.
Radar, the bomb and a bet
When war came, Rabi moved to the Radiation Laboratory at the Massachusetts Institute of Technology, created in 1940 to develop the British cavity magnetron into practical microwave radar. He became associate director and head of research, pushing the work toward shorter, three-centimetre wavelengths that gave sharper images, and set up a satellite laboratory at Columbia. Radar sets descended from this work flew in Allied bombers and sailed on Allied warships.
Oppenheimer wanted him at Los Alamos. Rabi declined to move but became a trusted consultant to the Manhattan Project, and he and Robert Bacher persuaded Oppenheimer that the laboratory must be run as a civilian institution rather than a military post. He was present at the Trinity test in July 1945. Arriving late to the scientists’ betting pool on the bomb’s yield, he took the only number left, 18 kilotons; the blast came in at about 18.6, and Rabi won.
Building the institutions of postwar science
After the war Rabi chaired Columbia’s physics department from 1945 to 1949, presiding over an astonishing concentration of present and future Nobel laureates. In a 1945 lecture he proposed that atomic resonance might be used to keep time; Zacharias and Ramsey soon built such atomic clocks, the ancestors of the timekeeping behind GPS. He helped organise the consortium of nine universities that founded Brookhaven National Laboratory on Long Island in 1947.
As American delegate to UNESCO, he called at a 1950 meeting in Florence for regional research laboratories to help rebuild European science. In 1952, eleven countries came together to create CERN, the European Organization for Nuclear Research. Bohr, Heisenberg and others wrote to thank him; he framed the letter and hung it in his study.
Conscience of the nuclear age
Appointed to the Atomic Energy Commission’s General Advisory Committee in 1946, Rabi joined Enrico Fermi in opposing development of the hydrogen bomb on moral as well as technical grounds; in January 1950 President Truman overruled the committee. Rabi succeeded Oppenheimer as chairman of the committee in 1952, and in 1954, when Oppenheimer’s security clearance was put on trial, Rabi was among his most forceful defenders, asking the board what more it could want from a man who had given the country the atomic bomb.
He chaired the Science Advisory Committee of the Office of Defense Mobilization, and after the Soviet launch of Sputnik in October 1957 his advice to President Eisenhower, whom he knew from Eisenhower’s years as Columbia’s president, helped turn it into the President’s Science Advisory Committee. In 1964 Columbia made him its first University Professor, the institution’s highest academic rank.
A proud Jew
Rabi left religious observance behind in childhood, but never his identity. He had come of age when Jewish scientists were shut out of industry and much of academia, and he faced that prejudice directly. Yet late in life he said that he had always made it clear he was a Jew and had found it an advantage. He described himself as a proud Jew and an admirer of Israel. He sat on the board of governors of the Weizmann Institute of Science from 1959, served on the science advisory committee of Bar-Ilan University, and in June 1987, months before his death, received an honorary doctorate from Bar-Ilan.
Last days and legacy
Rabi died of cancer at his home on Riverside Drive in Manhattan on January 11, 1988, aged eighty-nine, after a sixty-three-year association with Columbia. Helen, his wife of more than sixty years, survived him and lived to 102. In his final illness he was examined in a magnetic resonance imaging scanner, a machine descended directly from his own experiments. Seeing his reflection in its curved interior, he remarked that he had seen himself in the machine and had never thought his work would come to this.
That is his practical legacy: magnetic resonance underlies MRI scanners in hospitals worldwide, the NMR spectroscopy chemists use to identify molecules, and the atomic clocks that keep global time. His institutional legacy, from Brookhaven to CERN, is just as large. And through the students and colleagues he gathered, several of whom won Nobel Prizes of their own, the Yiddish-speaking tailor’s son from Galicia shaped American physics for half a century.
Sources & further reading
Isidor Isaac Rabi, Wikipedia · Nobel Laureate Physicist Isidor Isaac Rabi Dead at 89, JTA (1988) · Isidor I. Rabi, Atomic Heritage Foundation · 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.