Raphael Bousso () (born 1971) is a

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict natural phenomena. This is in contrast to experimental physics, which uses experi ...

and cosmologist. He is a professor at the Berkeley Center for Theoretical Physics in the Department of Physics,

UC Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...

. He is known for the Bousso bound on the information content of the universe. With

Joseph Polchinski Joseph Gerard Polchinski Jr. (; May 16, 1954 – February 2, 2018) was an American theoretical physicist and string theorist. Biography Polchinski was born in White Plains, New York, the elder of two children to Joseph Gerard Polchinski Sr. (19 ...

, Bousso proposed the

string theory landscape In string theory, the string theory landscape (or landscape of vacua) is the collection of possible false vacua,The number of metastable vacua is not known exactly, but commonly quoted estimates are of the order 10500. See M. Douglas, "The stat ...

as a solution to the cosmological constant problem.

Life and career

Bousso was born in

Haifa Haifa ( ; , ; ) is the List of cities in Israel, third-largest city in Israel—after Jerusalem and Tel Aviv—with a population of in . The city of Haifa forms part of the Haifa metropolitan area, the third-most populous metropolitan area i ...

, Israel, the son of late scientist . He grew up near

Augsburg Augsburg ( , ; ; ) is a city in the Bavaria, Bavarian part of Swabia, Germany, around west of the Bavarian capital Munich. It is a College town, university town and the regional seat of the Swabia (administrative region), Swabia with a well ...

, Germany, where he studied physics from 1990 until 1993. Bousso earned his Ph.D. at

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

in 1997; his doctoral advisor was

Stephen Hawking Stephen William Hawking (8January 194214March 2018) was an English theoretical physics, theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge. Between ...

. Bousso did

postdoctoral research A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). Postdocs most commonly, but not always, have a temporary acade ...

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

until 2000, and at the

Kavli Institute for Theoretical Physics The Kavli Institute for Theoretical Physics (KITP) is a research institute of the University of California, Santa Barbara dedicated to theoretical physics. KITP is one of 20 Kavli Foundation (United_States)#The Kavli Institutes, Kavli Institutes ...

in Santa Barbara until 2002. In 2002/03, Bousso was a fellow at the

Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...

physics department and the

Radcliffe Institute for Advanced Study The Radcliffe Institute for Advanced Study at Harvard University, also known as the Harvard Radcliffe Institute, is an institute of Harvard University that fosters interdisciplinary research across the humanities, sciences, social sciences, arts ...

. Since 2002, he has been a professor in the physics department at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

. In 2012, Bousso was elected Fellow of the American Physical Society "for fundamental discoveries in the field of quantum cosmology, including the covariant entropy bound and the string landscape."

Research

Bousso's research is focused on

quantum gravity Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics. It deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the v ...

and

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...

, particularly through the study of

quantum information Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ...

. His 1999 covariant entropy bound ( Bousso bound) established a general relation between quantum information and the geometry of spacetime (i.e.,

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

). The Bousso bound has since been refined and strengthened, leading to provable new results in quantum field theory, such as the quantum null energy condition. Bousso has also worked on the black hole information paradox (firewall problem). Since 2018, he has led a consortium of theoretical and experimental physicists exploring and developing the relations between quantum gravity, quantum information, and quantum computing. In 2000, Bousso and

argued that

string theory In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and intera ...

has many long-lived vacua, including solutions compatible with the observed positive value of the

cosmological constant In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: ), alternatively called Einstein's cosmological constant, is a coefficient that Albert Einstein initially added to his field equations of general rel ...

(

vacuum energy Vacuum energy is an underlying background energy that exists in space throughout the entire universe. The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum. The effects of vacuum energy can be experiment ...

). This came to be called the "landscape of string theory." Bousso has developed an approach to the cosmological measure problem, with the ultimate goal of testing the string theory landscape.

Life and career

Research

References

External links