Editing Alan Guth

{{short description|American theoretical physicist and cosmologist}}
{{Use mdy dates|date=January 2021}}
{{Infobox scientist
| name              = Alan Guth
| image             = AlanGuthCambridge.jpg
| caption           = Guth at [[Trinity College, Cambridge]], 2007
| birth_name        = Alan Harvey Guth
| birth_date        = {{Birth date and age|1947|2|27}}
| birth_place       = [[New Brunswick, New Jersey]], U.S.
| death_date        = 
| death_place       = 
| nationality       = American
| field             = [[Cosmology]], [[theoretical physics]], [[particle physics]]
| work_institution  = [[Princeton University|Princeton]]<br>[[Columbia University|Columbia]]<br>[[Cornell University|Cornell]]<br>[[Stanford Linear Accelerator]]<br>[[Massachusetts Institute of Technology|MIT]]
| alma_mater        = [[Massachusetts Institute of Technology]] ([[B. S.|BS]], [[M. S.|MS]], [[PhD]])
| doctoral_advisor  = [[Francis E. Low]]
| doctoral_students = 
| known_for         = [[Cosmic inflation]]<br>[[Borde–Guth–Vilenkin theorem]]<br>[[Inflaton]]
| prizes            = [[Oskar Klein Memorial Lecture|Oskar Klein Medal]] (1991)<br>
[[Benjamin Franklin Medal (Franklin Institute)|Benjamin Franklin Medal]] for Physics of the [[Franklin Institute]]<br>
[[Institute of Physics Isaac Newton Medal]] (2009)<br>
[[Dirac Medal (ICTP)|Dirac Prize]] of the International Center for Theoretical Physics in Trieste<br>
[[Gruber Prize in Cosmology]] (2004)<br>
[[Breakthrough Prize in Fundamental Physics]] (2012)<br>
[[Kavli Prize]] (2014)
| spouse            = {{marriage|Susan Tisch|1971}}
| children          = 2, including [[Larry Guth]]
| website           = 
| footnotes         = 
}}
{{Cosmology|scientists}}

'''Alan Harvey Guth''' ({{IPAc-en|g|uː|θ}}; born February 27, 1947) is an American [[theoretical physicist]] and [[cosmologist]] who is the [[Victor Weisskopf]] Professor of Physics at the [[Massachusetts Institute of Technology]]. Along with [[Alexei Starobinsky]] and [[Andrei Linde]], he won the 2014 [[Kavli Prize]] "for pioneering the theory of cosmic inflation."<ref name="KavliPrize">{{cite web |title=2014 Astrophysics Citation |url=http://www.kavlifoundation.org/2014-astrophysics-citation |url-status=dead |archive-url=https://web.archive.org/web/20140714114045/http://www.kavlifoundation.org/2014-astrophysics-citation |archive-date=July 14, 2014 |access-date=July 27, 2014 |website=The Kavli Foundation }}</ref> Guth's research focuses on [[elementary particle]] theory and how particle theory is applicable to the early [[universe]]. 
<!-- According to some sources, Guth is the originator of the [[cosmic inflation|inflationary universe theory]];<ref>[http://www.pbs.org/wnet/hawking/mysteries/html/guth_1.html PBS Unsolved Mysteries]</ref><ref>[https://www.nytimes.com/2006/03/16/science/16cnd-cosmic.html?pagewanted=1&sq&st=cse%22alan%20guth%22&scp=3 ''New York Times'', March 16, 2006. "Scientists Get Glimpse of First Moments After Beginning of Time"]</ref> however, according to other sources, the originator was [[Alexei Starobinsky]].<ref name=LindeSciAm>[http://www.mukto-mona.com/science/physics/Inflation_lself_prod_inde.pdf The Self-Reproducing Inflationary Universe] by Andrei Linde, Scientific American, Volume 9, Issue 1 (1998) 98–104.</ref><ref name="JETP-19791205">{{cite journal |last=Starobinskii |first=A.A. |title=Spectrum of relict gravitational radiation and the early state of the universe |url=http://www.jetpletters.ac.ru/ps/1370/article_20738.shtml |date=December 5, 1979 |journal=[[Journal of Experimental and Theoretical Physics|JETP]] |volume=30 |issue=11 |page=682 |format=http://www.jetpletters.ac.ru/ps/1370/article_20738.pdf |access-date=June 14, 2014}}</ref> -->

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 1979 at [[Cornell University|Cornell]] and gave his first seminar on the subject in January 1980.<ref>{{citation |last1=Guth |first1=Alan H. |title=[[The Inflationary Universe]] |publisher=Perseus Books |location=Reading, Massachusetts |date=1997 |isbn=0-201-14942-7}}</ref><ref name="SLAC">[[Stanford Linear Accelerator Center|SLAC]] seminar, "10-35 seconds after the Big Bang", January 23, 1980. see Guth (1997), pg 186.</ref> Moving on to the [[SLAC Theory Group]] at [[Stanford University]], 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<ref>{{Cite web |url=https://news.nationalgeographic.com/news/innovators/2014/06/140630-alan-guth-profile-inflation-cosmology-science/ |archive-url=https://web.archive.org/web/20140702172441/http://news.nationalgeographic.com/news/innovators/2014/06/140630-alan-guth-profile-inflation-cosmology-science/ |url-status=dead |archive-date=July 2, 2014 |title=Alan Guth: Waiting for the Big Bang }}</ref> in [[New Brunswick, New Jersey]] in 1947 and grew up across the [[Raritan River]] in [[Highland Park, New Jersey|Highland Park]], where he attended the local public schools.<ref>[https://www.aps.org/programs/honors/prizes/prizerecipient.cfm?last_nm=Guth&first_nm=Alan&year=1992 1992 Julius Edgar Lilienfeld Prize Recipient - Alan H. Guth], [[American Physical Society]]. Accessed January 23, 2018. "Professor Alan Guth was born in New Brunswick, New Jersey, in 1947. He grew up and attended the public schools in Highland Park, NJ, but skipped his senior year of high school to begin studies at the Massachusetts Institute of Technology."</ref> After his junior year at [[Highland Park High School (New Jersey)|Highland Park High School]],<ref name=":0">{{Cite news |date=1 Feb 1971 |title=Susan Tisch, Alan H Guth Plan to Wed |pages=7 |work=[[Home News Tribune|The Central New Jersey Home News]] |url=https://www.newspapers.com/image/316046041 |access-date=26 May 2023}}</ref> he left school and enrolled in a five-year program at the [[Massachusetts Institute of Technology]] where he could get his [[bachelor's degree|bachelor's]] and [[master's degree|master's]] after two more years.<ref>[https://books.google.com/books?id=yooYAAAAIAAJ&q=highland+park+high+school+Alan+Guth ''Current Biography Yearbook, Volume 48''], p. 219. [[H. W. Wilson Company]], 1988. Accessed January 23, 2018. "At the end of his junior year he left Highland Park (New Jersey) High School to enter the Massachusetts Institute of Technology, where his extracurricular activities included, as they had in high school, debating, track, and the mathematics club."</ref> 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.<ref name=":0" /> They have two children: [[Larry Guth|Lawrence]] (born 1977) and Jennifer (born 1983).<ref name="Cosmos2015">{{Cite web |url=https://cosmosmagazine.com/space/physicist-who-inflated-universe |title=The physicist who inflated the Universe |last=da Silva |first=Wilson |work=Cosmos |quote=When people said that gravitational waves would be the smoking gun for inflation, my response was that I thought the room was pretty filled with smoke already. |date=March 2, 2015 |access-date=February 20, 2020}}</ref>

Guth was at [[Princeton University|Princeton]] 1971 to 1974, [[Columbia University|Columbia]] 1974 to 1977, [[Cornell University|Cornell]] 1977 to 1979, and the [[Stanford Linear Accelerator Center]] (SLAC) 1979 to 1980. Like many other young physicists of the [[Baby boomers|baby boom]] 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."<ref>{{cite web |date=1978 |publisher=Carnegie Council on Policy Studies in Higher Education |title=Preserving a Lost Generation: Policies to Assure a Steady Flow of Young Scholars Until the Year 2000 |url=http://pages.stern.nyu.edu/~rradner/publishedpapers/42PreservingLostGeneration.pdf |access-date=July 9, 2011 }}</ref>

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]]s, the elementary particles that make up protons and neutrons. At Columbia, Guth studied [[grand unification theories]] (GUTs), focusing on the [[cosmological 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===
{{main|Cosmic inflation}}
{{BLP sources section|date=July 2014}}
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.<ref>{{cite book |author-link=Timothy Ferris |author=Ferris, Timothy |url=https://books.google.com/books?id=k0vCHGD5Y00C&pg=PA356 |via=Google Books |title=Coming of Age in the Milky Way |date=July 6, 2010 |page=356|publisher=Harper Collins |isbn=9780062006547 }}</ref> Dicke explained how the flatness problem showed that something significant was missing from the [[Big Bang]] 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 [[Gravitational singularity|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.<ref name="Swidey-2014">{{cite web |last1=Swidey |first1=Neil |title=Alan Guth: What made the Big Bang bang? |url=https://www.bostonglobe.com/magazine/2014/05/02/alan-guth-what-made-big-bang-bang/RmI4s9yCI56jKF6ddMiF4L/story.html |publisher=The Boston Globe |access-date=July 14, 2015 |date=May 2, 2014 |archive-date=February 27, 2019 |archive-url=https://web.archive.org/web/20190227040746/https://www.bostonglobe.com/magazine/2014/05/02/alan-guth-what-made-big-bang-bang/RmI4s9yCI56jKF6ddMiF4L/story.html |url-status=dead }}</ref> 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 transition]]s, 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]] came up with that, Guth had gone to the [[SLAC National Accelerator Laboratory|Stanford Linear Accelerator Center]] (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 [[Density parameter#Density parameter|omega]] near&nbsp;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&nbsp;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&nbsp;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&nbsp;years after the Big Bang, the observable universe had a diameter of 90&nbsp;million [[light-year]]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{{vague|date=August 2019}} 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&nbsp;1980. He ignored magnetic monopoles because they were based on assumptions of GUT, which was outside the scope of the speech. In August&nbsp;1980, he submitted his paper, entitled "Inflationary universe: A possible solution to the horizon and flatness problems" to the journal ''[[Physical Review]]''.<ref name="Inflationary Universe">{{cite journal |last1=Guth |first1=Alan H. |title=Inflationary universe: A possible solution to the horizon and flatness problems |journal=Physical Review D |year=1981 |volume=23 |issue=2 |pages=347–356 |doi=10.1103/PhysRevD.23.347 |bibcode=1981PhRvD..23..347G|doi-access=free }}</ref>  In this paper Guth postulated that the inflation of the universe could be explained if the universe were supercooled 28&nbsp;orders of magnitude below the critical temperatures required for a phase change.

In December&nbsp;1981, Guth read a paper from Moscow physicist [[Andrei Linde]] 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]]. 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.<ref name=KavliPrize/><ref name=LindeSciAm>{{cite magazine |url=http://www.mukto-mona.com/science/physics/Inflation_lself_prod_inde.pdf |title=The self-reproducing inflationary universe |first=Andrei |last=Linde |magazine=Scientific American |volume=9 |issue=1 |year=1998 |pages=98–104}}</ref><ref>{{cite journal |last1=Guth |first1=Alan H. |last2=Weinberg |first2=Erick J. |title=Could the universe have recovered from a slow first-order phase transition? |journal=Nuclear Physics B |year=1983 |volume=212 |issue=2 |pages=321–364 |doi=10.1016/0550-3213(83)90307-3 |bibcode=1983NuPhB.212..321G}}</ref> However, this did not deter him from the belief that the universe expanded exponentially in a vacuum in its early lifetime.<ref>{{cite journal |last1=GUTH |first1=ALAN H. |title=The New Inflationary Universe |journal=Annals of the New York Academy of Sciences |year=1984 |volume=422 |issue=1 Eleventh Texa |pages=1–14 |doi=10.1111/j.1749-6632.1984.tb23336.x |bibcode=1984NYASA.422....1G|s2cid=117856496 }}</ref>

==Current interests==
In the past, Guth has studied [[lattice gauge theory]], magnetic monopoles and [[instanton]]s, [[J. Richard Gott#Exotic matter time travel theories|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]]" models.

He is the [[Victor Frederick Weisskopf|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 [[Andrei Linde]] and [[Paul Steinhardt]] and the [[Eddington Medal]] in 1996, and the [[Isaac Newton Medal|2009 Isaac Newton Medal]], awarded by the British [[Institute of Physics]].

In July 2012, he was an inaugural awardee of the [[Breakthrough Prize in Fundamental Physics]], the creation of physicist and internet entrepreneur, [[Yuri Milner]].<ref>[https://breakthroughprize.org/News/15 New annual US$3 million Fundamental Physics Prize recognizes transformative advances in the field] {{webarchive|url=https://web.archive.org/web/20120803211628/https://breakthroughprize.org/News/15 |date=August 3, 2012 }}, FPP, accessed August 1, 2012.</ref><ref name="NYT_Breakthrough">{{Cite web |url=https://www.nytimes.com/2012/07/31/science/9-scientists-win-yuri-milners-fundamental-physics-prize.html |title=xx |last=Chang |first=Kenneth |work=NY Times |quote=The nine are recipients of the Fundamental Physics Prize, established by Yuri Milner, a Russian physics student who dropped out of graduate school in 1989 and later earned billions investing in Internet companies like Facebook and Groupon. |date=July 31, 2012 |access-date=February 20, 2020}}</ref>

In 2014, he was a co-recipient of the [[Kavli Prize]] awarded by the [[Norwegian Academy of Science and Letters]], together with [[Andrei Linde]] of [[Stanford University]], and [[Alexei Starobinsky]] of the [[Landau Institute for Theoretical Physics]], "for pioneering the theory of cosmic inflation."<ref name=KavliPrize /><ref name=AAAS>{{cite web |title=Nine Scientists Share Three Kavli Prizes |url=https://www.science.org/content/article/nine-scientists-share-three-kavli-prizes}}</ref><ref name="BosGlobe2014">{{Cite web |url=https://www.bostonglobe.com/news/science/2014/05/29/alan-guth-shares-million-kavli-astrophysics-prize/ |title=Alan Guth shares $1 million Kavli astrophysics prize |last=Johnson |first=Carolyn Y |work=Boston Globe |quote=It isn't the first time Guth's work has been honored. Last year, he received a $3 million award from the Fundamental Physics Prize Foundation. At the time, he told The New York Times that his bank account balance ballooned from $200 to $3,000,200. |date=May 29, 2014 |access-date=February 20, 2020}}</ref> That same year, Guth received the Golden Plate Award of the [[Academy of Achievement|American Academy of Achievement]].<ref>{{cite web|title= Golden Plate Awardees of the American Academy of Achievement |website=www.achievement.org|publisher=[[American Academy of Achievement]]|url=https://achievement.org/our-history/golden-plate-awards/#science-exploration}}</ref>

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,<ref>[https://web.archive.org/web/20160304062904/http://www.boston.com/realestate/galleries/springsweep/14.htm Boston Globe photos of winning entry]</ref> but Guth is quite proud of the award.<ref>[[Alexander Vilenkin]], ''Many Worlds in One: The Search for Other Universes'', {{ISBN|978-0-8090-9523-0}}, page 51 for photo'.</ref>

==Publications==
* {{cite book |author1=Guth, Alan |author-link1=Alan Guth |title=[[The Inflationary Universe|The Inflationary Universe: The Quest for a New Theory of Cosmic Origins]] |date=1997 |publisher=Perseus Books |isbn=0201328402}}
* {{cite web |author1=Guth, Alan |author-link1=Alan Guth |title=Inflation and the New Era of High-Precision Cosmology |url=https://physics.mit.edu/wp-content/uploads/2021/01/physicsatmit_02_cosmology.pdf |website=physics@mit |publisher=MIT Department of Physics |date=Fall 2002}}

==See also==
{{Portal|Biographies|Physics}}
*[[MIT Center for Theoretical Physics]]
*[[MIT Physics Department]]
{{clear}}

==References==
{{Reflist|30em}}

==External links==
{{wikiquote}}
*[http://web.mit.edu/physics/people/faculty/guth_alan.html Alan H. Guth's webpage at MIT]
*[http://ctp.lns.mit.edu/ MIT Center for Theoretical Physics]
*Alan Guth - "''[https://web.archive.org/web/20120414223036/http://pauli.physics.lsa.umich.edu/w/arch/som/sto2001/Guth/real/n001.htm Eternal inflation]: Successes and questions''"
*[https://web.archive.org/web/20061002183844/http://www.symmetrymag.org/cms/?pid=1000045 The Growth of Inflation], ''Symmetry'' magazine, December 2004/January 2005
*[http://discovermagazine.com/2002/apr/cover/?searchterm=Guth%27s%20Grand%20Guess Guth's Grand Guess], ''[[Discover (magazine)|Discover]]'' magazine, April 2002
*[https://web.archive.org/web/20081121174617/http://rowinphoto.com/people/guth.html  Additional photo]
*[https://arxiv.org/abs/gr-qc/0110012 Inflationary spacetimes are not past-complete]

{{Breakthrough Prize laureates}}
{{Kavli Prize laureates}}
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{{DEFAULTSORT:Guth, Alan}}
[[Category:1947 births]]
[[Category:Living people]]
[[Category:21st-century American physicists]]
[[Category:American cosmologists]]
[[Category:Columbia University faculty]]
[[Category:Members of the United States National Academy of Sciences]]
[[Category:Jewish American scientists]]
[[Category:Highland Park High School (New Jersey) alumni]]
[[Category:People from Highland Park, New Jersey]]
[[Category:People from New Brunswick, New Jersey]]
[[Category:Members of the Norwegian Academy of Science and Letters]]
[[Category:American string theorists]]
[[Category:MIT Center for Theoretical Physics faculty]]
[[Category:MIT Center for Theoretical Physics people]]
[[Category:Massachusetts Institute of Technology School of Science alumni]]
[[Category:Kavli Prize laureates in Astrophysics]]
[[Category:Fellows of the American Physical Society]]
[[Category:21st-century American Jews]]
[[Category:Benjamin Franklin Medal (Franklin Institute) laureates]]