Steven Weinberg

Steven Weinberg (May 3, 1933 – July 23, 2021) was an American theoretical physicist and Nobel laureate in physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interaction between elementary particles.

He held the Josey Regental Chair in Science at the University of Texas at Austin, where he was a member of the Physics and Astronomy Departments.

Steven Weinberg was born in 1933 in New York City.

His parents were Jewish immigrants; his father, Frederick, worked as a court stenographer, while his mother, Eva (Israel), was a housewife.

Becoming interested in science at age 16 through a chemistry set handed down by a cousin, he graduated from Bronx High School of Science in 1950.

Weinberg received his bachelor's degree from Cornell University in 1954.

There he resided at the Telluride House.

He then went to the Niels Bohr Institute in Copenhagen, where he started his graduate studies and research.

After one year, Weinberg moved to Princeton University, where he earned his Ph.D. in physics in 1957, completing his dissertation, "The role of strong interactions in decay processes", under the supervision of Sam Treiman.

After completing his Ph.D., Weinberg worked as a postdoctoral researcher at Columbia University (1957–59) and University of California, Berkeley (1959) and then was promoted to faculty at Berkeley (1960–66).

He did research in a variety of topics of particle physics, such as the high energy behavior of quantum field theory, symmetry breaking, pion scattering, infrared photons and quantum gravity.

It was also during this time that he developed the approach to quantum field theory described in the first chapters of his book The Quantum Theory of Fields and started to write his textbook Gravitation and Cosmology, having taken up an interest in general relativity after the discovery of cosmic microwave background radiation.

He was also appointed the senior scientist at the Smithsonian Astrophysical Observatory.

The Quantum Theory of Fields spanned three volumes and over 1,500 pages, and is often regarded as the leading book in the field.

Weinberg's model, now known as the electroweak unification theory, had the same symmetry structure as that proposed by Glashow in 1961: both included the then-unknown weak interaction mechanism between leptons, known as neutral current and mediated by the Z boson.

In 1966, Weinberg left Berkeley and accepted a lecturer position at Harvard.

In 1967 he was a visiting professor at MIT.

It was in that year at MIT that Weinberg proposed his model of unification of electromagnetism and nuclear weak forces (such as those involved in beta-decay and kaon-decay), with the masses of the force-carriers of the weak part of the interaction being explained by spontaneous symmetry breaking.

One of its fundamental aspects was the prediction of the existence of the Higgs boson.

After his 1967 seminal work on the unification of weak and electromagnetic interactions, Weinberg continued his work in many aspects of particle physics, quantum field theory, gravity, supersymmetry, superstrings and cosmology.

In the years after 1967, the full Standard Model of elementary particle theory was developed through the work of many contributors.

In it, the weak and electromagnetic interactions already unified by the work of Weinberg, Salam and Glashow, are made consistent with a theory of the strong interactions between quarks, in one overarching theory.

Also during the 1970s, he proposed a theory later known as technicolor, in which new strong interactions resolve the hierarchy problem.

The 1973 experimental discovery of weak neutral currents (mediated by this Z boson) was one verification of the electroweak unification.

The paper by Weinberg in which he presented this theory is one of the most cited works ever in high-energy physics.

In 1973, Weinberg proposed a modification of the Standard Model that did not contain that model's fundamental Higgs boson.

Weinberg became Eugene Higgins Professor of Physics at Harvard University in 1973, a post he held until 1983.

His research on elementary particles and physical cosmology was honored with numerous prizes and awards, including the 1979 Nobel Prize in physics and the 1991 National Medal of Science.

He was in the same graduating class as Sheldon Glashow, whose research, independent of Weinberg's, resulted in their (and Abdus Salam's) sharing the 1979 Nobel in physics.

In 1979 he pioneered the modern view on the renormalization aspect of quantum field theory that considers all quantum field theories effective field theories and changed the viewpoint of previous work (including his own in his 1967 paper) that a sensible quantum field theory must be renormalizable.

This approach allowed the development of effective theory of quantum gravity, low energy QCD, heavy quark effective field theory and other developments, and is a topic of considerable interest in current research.

In 1979, some six years after the experimental discovery of the neutral currents—i.e. the discovery of the inferred existence of the Z boson—but after the 1978 experimental discovery of the theory's predicted amount of parity violation due to Z bosons' mixing with electromagnetic interactions, Weinberg was awarded the Nobel Prize in physics with Glashow and Salam, who had independently proposed a theory of electroweak unification based on spontaneous symmetry breaking.

In 1982 Weinberg moved to the University of Texas at Austin as the Jack S. Josey-Welch Foundation Regents Chair in Science, and started a theoretical physics group at the university that now has eight full professors and is one of the leading research groups in the field in the U.S.

Weinberg is frequently listed among the top scientists with the highest research effect indices, such as the h-index and the creativity index.

The theoretical physicist Peter Woit called Weinberg "arguably the dominant figure in theoretical particle physics during its period of great success from the late sixties to the early eighties", calling his contribution to electroweak unification "to this day at the center of the Standard Model, our best understanding of fundamental physics".

Science News named him along with fellow theorists Murray Gell-Mann and Richard Feynman the leading physicists of the era, commenting, "Among his peers, Weinberg was one of the most respected figures in all of physics or perhaps all of science".

In 2004, he received the Benjamin Franklin Medal of the American Philosophical Society, with a citation that said he was "considered by many to be the preeminent theoretical physicist alive in the world today."

He was elected to the U.S. National Academy of Sciences, Britain's Royal Society, the American Philosophical Society, and the American Academy of Arts and Sciences.

Weinberg's articles on various subjects occasionally appeared in The New York Review of Books and other periodicals.

He served as a consultant at the U.S. Arms Control and Disarmament Agency, president of the Philosophical Society of Texas, and member of the Board of Editors of Daedalus magazine, the Council of Scholars of the Library of Congress, the JASON group of defense consultants, and many other boards and committees.