Leonard Emanuel Parker (born Leonard Pearlman in 1938 in

Brooklyn Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York. Kings County is the most populous county in the State of New York, and the second-most densely populated county in the United States, be ...

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

) is a Distinguished Professor Emeritus of

Physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

and a former Director of the Center for Gravitation and Cosmology at the

University of Wisconsin–Milwaukee The University of Wisconsin–Milwaukee (UW–Milwaukee, UWM, or Milwaukee) is a public urban research university in Milwaukee, Wisconsin. It is the largest university in the Milwaukee metropolitan area and a member of the University of Wiscons ...

. During the late 1960s, Parker established a new area of physics—

quantum field theory in curved spacetime In theoretical physics, quantum field theory in curved spacetime (QFTCS) is an extension of quantum field theory from Minkowski spacetime to a general curved spacetime. This theory treats spacetime as a fixed, classical background, while giving ...

. Specifically, by applying the technique of

Bogoliubov transformation In theoretical physics, the Bogoliubov transformation, also known as the Bogoliubov–Valatin transformation, was independently developed in 1958 by Nikolay Bogolyubov and John George Valatin for finding solutions of BCS theory in a homogeneous s ...

s to

quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and ...

with a changing gravitational field, he discovered the physical mechanism now known as cosmological particle production. His breakthrough discovery has a surprising consequence: the expansion of the universe can create particles out of the vacuum. His work inspired research by hundreds of physicists and has been cited in more than 2,000 research papers; it was credited in the memoirs of Soviet physicist

Andrei Sakharov Andrei Dmitrievich Sakharov ( rus, Андрей Дмитриевич Сахаров, p=ɐnˈdrʲej ˈdmʲitrʲɪjevʲɪtɕ ˈsaxərəf; 21 May 192114 December 1989) was a Soviet nuclear physicist, dissident, nobel laureate and activist for nu ...

and helped Stephen Hawking discover the creation of particles by

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

s. Along with David Toms of

Newcastle University Newcastle University (legally the University of Newcastle upon Tyne) is a UK public university, public research university based in Newcastle upon Tyne, North East England. It has overseas campuses in Singapore and Malaysia. The university is ...

, Parker co-wrote a latest addition to graduate-level textbooks on quantum field theory in curved spacetime, entitled ''Quantum Field Theory in Curved Spacetime: Quantized Fields and Gravity'' (

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing hou ...

, 2009, ). He received his PhD from

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

in 1967. His advisor was

Sidney Coleman Sidney Richard Coleman (7 March 1937 – 18 November 2007) was an American theoretical physics, theoretical physicist noted for his research in high-energy theoretical physics. Life and work Sidney Coleman grew up on the Far North Side o ...

Awards and honors

*1984 Elected Fellow,

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of k ...

*200
The Parker symposium

References

External links

Parker's faculty page at University of Wisconsin–Milwaukee

The Center for Gravitation and Cosmology

Milwaukee Journal Sentinel article about Leonard Parker
Living people 20th-century American Jews 21st-century American physicists American cosmologists People from Brooklyn Harvard University alumni Scientists from Milwaukee University of Wisconsin–Milwaukee faculty 1938 births Scientists from New York (state) 21st-century American Jews {{US-physicist-stub