Alan Harvey Guth (; born February 27, 1947) is an American theoretical physicist and cosmologist. Guth has researched elementary particle theory (and how particle theory is applicable to the early universe). He is Victor Weisskopf Professor of Physics at the Massachusetts Institute of Technology. Along with

Alexei Starobinsky Alexei Alexandrovich Starobinsky (russian: Алексе́й Алекса́ндрович Староби́нский; born 19 April 1948) is a Soviet and Russian astrophysicist and cosmologist. He received the Kavli Prize in Astrophysics "for p ...

and

Andrei Linde Andrei Dmitriyevich Linde (russian: Андре́й Дми́триевич Ли́нде; born March 2, 1948) is a Russian-American theoretical physicist and the Harald Trap Friis Professor of Physics at Stanford University. Linde is one of the ...

, he won the 2014 Kavli Prize "for pioneering the theory of cosmic inflation." He graduated from MIT in 1968 in physics and stayed to receive a master's and a doctorate, also in physics. As a junior particle physicist, Guth developed the idea of

cosmic inflation In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from seconds after the conjectured Big Bang singularity ...

in 1979 at Cornell and gave his first seminar on the subject in January 1980. SLAC seminar, "10-35 seconds after the Big Bang", January 23, 1980. see Guth (1997), pg 186. Moving on to the SLAC Theory Group at

Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...

Guth formally proposed the idea of cosmic inflation in 1981, the idea that the nascent universe passed through a phase of exponential expansion that was driven by a positive vacuum energy density (negative vacuum pressure). The results of the WMAP mission in 2006 made the case for cosmic inflation very compelling.

Early life and education

Guth was born to a Jewish family in

New Brunswick, New Jersey New Brunswick is a city (New Jersey), city in and the county seat, seat of government of Middlesex County, New Jersey, Middlesex County, in the U.S. state of New Jersey.Raritan River in Highland Park, where he attended the local public schools. After his junior year at Highland Park High School, he left school and enrolled in a five-year program at the Massachusetts Institute of Technology where he could get his

bachelor's A bachelor's degree (from Middle Latin ''baccalaureus'') or baccalaureate (from Modern Latin ''baccalaureatus'') is an undergraduate academic degree awarded by colleges and universities upon completion of a course of study lasting three to six ye ...

and master's after two more years. Guth obtained a bachelor's and master's degree in 1969 and a doctorate in 1972. In 1971, he married Susan Tisch, his high school sweetheart. They have two children: Lawrence (born 1977) and Jennifer (born 1983). Guth was at Princeton 1971 to 1974,

Columbia Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region in ...

1974 to 1977, Cornell 1977 to 1979, and the

Stanford Linear Accelerator Center SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...

(SLAC) 1979 to 1980. Like many other young physicists of the

baby boom A baby boom is a period marked by a significant increase of birth rate. This demographic phenomenon is usually ascribed within certain geographical bounds of defined national and cultural populations. People born during these periods are often ca ...

era, he had a hard time finding a permanent job, because there were far fewer assistant professorships than there were young scientists seeking such jobs, a phenomenon that has been referred to as the "generation of lost scholars." At the start of his career, Guth studied particle physics, not physical cosmology. Guth's earliest work at Princeton was in the study of

quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly o ...

s, the elementary particles that make up protons and neutrons. At Columbia, Guth studied

grand unification theories A Grand Unified Theory (GUT) is a model in particle physics in which, at high energies, the three gauge interactions of the Standard Model comprising the electromagnetic, weak, and strong forces are merged into a single force. Although this u ...

(GUTs), focusing on the phase transitions generated by spontaneous symmetry breaking. Most GUTs predict the generation of magnetic monopoles during spontaneous symmetry breaking, but none had ever been detected—the monopole problem.

Career

Inflationary theory

Guth's first step to developing his theory of inflation occurred at Cornell in 1978, when he attended a lecture by Robert Dicke about the flatness problem of the universe. Dicke explained how the flatness problem showed that something significant was missing from the

Big Bang The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the ...

theory at the time. The fate of the universe depended on its density. If the density of the universe was large enough, it would collapse into a singularity, and if the actual density of the matter in the cosmos was lower than the critical density, the universe would increasingly get much bigger. The next part in Guth's path came when he heard a lecture by Steven Weinberg in early 1979. Weinberg talked in two lectures about the Grand Unified Theory (GUT) that had been developed since 1974, and how it could explain the huge amount of matter in the universe compared to the amount of antimatter. The GUT explained all the fundamental forces known in science except for gravity. It established that in very hot conditions, such as those after the Big Bang, electromagnetism, the strong nuclear force, and the weak nuclear force were united to form one force. Weinberg also was the one who emphasized the idea that the universe goes through phase transitions, similar to the phases of matter, when going from high energy to low energy. Weinberg's discussion of why matter is so dominant over anti-matter showed Guth how precise calculations about particles could be obtained by studying the first few seconds of the universe. Guth decided to solve this problem by suggesting a supercooling during a delayed phase transition. This seemed very promising for solving the magnetic monopole problem. By the time Guth and his collaborator

Henry Tye Sze-Hoi Henry Tye (; born 1947 in Shanghai, China) is a Chinese-American cosmologist and theoretical physicist most notable for proposing that relative brane motion could cause cosmic inflation as well as his work on superstring theory, brane cosm ...

came up with that, Guth had gone to the

(SLAC) for a year. Tye suggested that they check that the expansion of the universe would not be affected by the supercooling. The supercooled state is a false vacuum: It is a ''vacuum'' in the sense that it is the state of the lowest possible density of energy; it is "false" since its state is not permanent. False vacuums decay, and Guth found that the decay of the false vacuum at the beginning of the universe would produce an exponential expansion of space. This solved the monopole problem, since the expansion proportionately reduces the monopole density. Guth realized from his theory that the reason the universe appears to be flat was that it had enlarged to such an overwhelming size in comparison to its original size. The perspective is analogous to the apparent flatness of the Earth, on a human scale, when seen from its surface. The ''observable'' universe was actually only a very small part of the ''actual'' universe. Traditional Big Bang theory found values of omega near 1 to be puzzling, because any deviations from 1 would quickly become much, much larger. In inflation theory, no matter where omega starts, it would approach 1 because of the scale of the universe's expansion. In fact, a major prediction of inflationary theory is that omega will be found to be precisely 1. Two weeks later, Guth heard colleagues discussing something called the horizon problem. The microwave background radiation discovered by Arno Penzias and Robert Woodrow Wilson appeared extremely uniform, with almost no variance. This seemed very paradoxical because when the radiation was released about 300,000 years after the Big Bang, the observable universe had a diameter of 90 million

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s. There was no time for one end of the cosmos to communicate with the other end, because energy cannot move faster than the speed of light. The paradox was resolved, as Guth soon realized, by the inflation theory. Since inflation started with a far smaller amount of matter than the Big Bang had presupposed, an amount so small that all parts would have been in touch with each other. The universe then inflated, at a rate corresponding to a billion times the speed of light, and the homogeneity remained unbroken. The universe after inflation would have been very uniform, even though its parts were no longer able to influence each other. Guth first made public his ideas on inflation in a seminar at SLAC in January 1980. He ignored magnetic monopoles because they were based on assumptions of GUT, which was outside the scope of the speech. In August 1980, he submitted his paper, entitled "Inflationary universe: A possible solution to the horizon and flatness problems" to the journal ''

Physical Review ''Physical Review'' is a peer-reviewed scientific journal established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical S ...

''. In this paper Guth postulated that the inflation of the universe could be explained if the universe were supercooled 28 orders of magnitude below the critical temperatures required for a phase change. In December 1981, Guth read a paper from Moscow physicist

saying that the whole universe is within just one bubble, so nothing is destroyed by wall collisions. This conclusion was made using a Higgs field with an energy graph that was originally proposed by Sidney Coleman and

Erick Weinberg Erick J. Weinberg (born August 29, 1947) is a theoretical physicist and professor of physics at Columbia University. Weinberg received his undergraduate degree from Manhattan College in 1968. He obtained his Ph.D. from Harvard University in 1973 ...

. Guth discussed this with Linde, who had independently been working on bubble inflation, but without considering the flatness problem. Linde and Guth eventually exchanged papers on the subject. By 1983, Guth had published a paper describing how his supercooled universe scenario was not ideal, as the "triggering mechanism" to exit such a state would require "extreme fine tuning of parameters" and felt a more natural solution was required. However, this did not deter him from the belief that the universe expanded exponentially in a vacuum in its early lifetime.

Current interests

In the past, Guth has studied lattice gauge theory, magnetic monopoles and instantons, Gott time machines, and a number of other topics in theoretical physics. Much of Guth's current work includes extrapolating density fluctuations arising from various versions of inflation, to test against observations, and investigating inflation in "

brane world Brane cosmology refers to several theories in particle physics and cosmology related to string theory, superstring theory and M-theory. Brane and bulk The central idea is that the visible, three-dimensional universe is restricted to a b ...

" models. He is the Victor F. Weisskopf Professor of Physics at the Massachusetts Institute of Technology (MIT). He has written more than 60 technical papers related to the effects of inflation and its interactions with particle physics.

Honors and awards

Guth has won many awards and medals, including the Medal of the International Center for Theoretical Physics, Trieste, Italy, with

and Paul Steinhardt and the Eddington Medal in 1996, and the 2009 Isaac Newton Medal, awarded by the British Institute of Physics. In July 2012, he was an inaugural awardee of the Fundamental Physics Prize, the creation of physicist and internet entrepreneur, Yuri Milner. In 2014, he was a co-recipient of the Kavli Prize awarded by the Norwegian Academy of Science and Letters, together with

, and

of the Landau Institute for Theoretical Physics, "for pioneering the theory of cosmic inflation." That same year, Guth received the Golden Plate Award of the American Academy of Achievement. In 2005, Guth won the award for the messiest office in Boston, organised by the Boston Globe. He was entered by colleagues who hoped it would shame him into tidying up, but Guth is quite proud of the award. Alexander Vilenkin, ''Many Worlds in One: The Search for Other Universes'', , page 51 for photo'.

Publications

* *

References

External links

Alan H. Guth's webpage at MITMIT Center for Theoretical Physics
*Alan Guth - "

Successes and questions''"
The Growth of Inflation
Symmetry magazine, December 2004/January 2005
Guth's Grand Guess
Discover magazine, April 2002
Additional photoInflationary spacetimes are not past-complete
{{DEFAULTSORT:Guth, Alan 1947 births Living people 21st-century American physicists American cosmologists Columbia University faculty Members of the United States National Academy of Sciences Jewish American scientists Highland Park High School (New Jersey) alumni People from Highland Park, New Jersey People from New Brunswick, New Jersey Members of the Norwegian Academy of Science and Letters American string theorists MIT Center for Theoretical Physics faculty MIT Center for Theoretical Physics alumni MIT Department of Physics alumni Kavli Prize laureates in Astrophysics Fellows of the American Physical Society 21st-century American Jews