Julian Schwinger

Julian's older brother Harold Schwinger was born in 1911, seven years before Julian who was born in 1918.

Schwinger was a precocious student.

Julian Seymour Schwinger (February 12, 1918 – July 16, 1994) was a Nobel Prize-winning American theoretical physicist.

He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order.

Schwinger was a physics professor at several universities.

Schwinger is recognized as one of the greatest physicists of the twentieth century, responsible for much of modern quantum field theory, including a variational approach, and the equations of motion for quantum fields.

He developed the first electroweak model, and the first example of confinement in 1+1 dimensions.

He is responsible for the theory of multiple neutrinos, Schwinger terms, and the theory of the spin-3/2 field.

Julian Seymour Schwinger was born in New York City, to Ashkenazi Jewish parents, Belle (née Rosenfeld) and Benjamin Schwinger, a garment manufacturer, who had emigrated from Poland to the United States.

Both his father and his mother's parents were prosperous clothing manufacturers, although the family business declined after the Wall Street Crash of 1929.

The family followed the Orthodox Jewish tradition.

He attended the Townsend Harris High School from 1932 to 1934, a highly regarded high school for gifted students at the time.

During high school, Julian had already started reading Physical Review papers by authors such as Paul Dirac in the library of the City College of New York, in whose campus Townsend Harris was then located.

In the fall of 1934, Schwinger entered the City College of New York as an undergraduate.

CCNY automatically accepted all Townsend Harris graduates at the time, and both institutions offered free tuition.

Due to his intense interest in physics and mathematics, Julian performed very well in those subjects despite often skipping classes and learning directly from books.

On the other hand, his lack of interest for other topics such as English led to academic conflicts with teachers of those subjects.

After Julian had joined CCNY, his brother Harold, who had previously graduated from CCNY, asked his ex-classmate Lloyd Motz to "get to know [Julian]".

Lloyd was a CCNY physics instructor and Ph.D. candidate at Columbia University at the time.

Lloyd made the acquaintance, and soon recognized Julian's talent.

Noticing Schwinger's academic problems, Lloyd decided to ask Isidor Isaac Rabi who he knew at Columbia for help.

Rabi also immediately recognized Schwinger's capabilities on their first meeting, and then made arrangements to award Schwinger with a scholarship to study at Columbia.

At first Julian's bad grades in some subjects at CCNY prevented the scholarship award.

But Rabi persisted and showed an unpublished paper on quantum electrodynamics written by Schwinger to Hans Bethe, who happened to be passing by New York.

Bethe's approval of the paper and his reputation in that domain were then enough to secure the scholarship for Julian, who then transferred to Columbia.

His academic situation at Columbia was much better than at CCNY.

He was accepted into the Phi Beta Kappa society and received his B.A. in 1936.

During Schwinger's graduate studies, Rabi felt that it would be good for Julian to visit other institutions around the country, and Julian was awarded a travelling fellowship for the year 37/38 which he spent at working with Gregory Breit and Eugene Wigner.

During this time, Schwinger, who previously had already had the habit of working until late at night, went further and made the day/night switch more complete, working at night and sleeping during the day, a habit he would carry throughout his career.

Schwinger later commented that this switch was in part a way to retain greater intellectual independence and avoid being "dominated" by Breit and Wigner by simply reducing the duration of contact with them by working different hours.

Schwinger obtained his PhD overseen by Rabi in 1939 at the age of 21.

During the fall of 1939 Schwinger started working at the University of California, Berkeley under J. Robert Oppenheimer, where he stayed for two years as an NRC fellow.

After having worked with Oppenheimer, Schwinger's first regular academic appointment was at Purdue University in 1941.

While on leave from Purdue, he worked at the MIT Radiation Laboratory instead of at the Los Alamos National Laboratory during World War II.

He provided theoretical support for the development of radar.

After the war, Schwinger left Purdue for Harvard University, where he taught from 1945 to 1974.

In 1966 he became the Eugene Higgins professor of physics at Harvard.

Schwinger developed an affinity for Green's functions from his radar work, and he used these methods to formulate quantum field theory in terms of local Green's functions in a relativistically invariant way.

This allowed him to calculate unambiguously the first corrections to the electron magnetic moment in quantum electrodynamics.

Earlier non-covariant work had arrived at infinite answers, but the extra symmetry in his methods allowed Schwinger to isolate the correct finite corrections.