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| doctoral_students = | notable_students = | known_for = | influences = | influenced = | prizes = | website = }} Paul Joseph Steinhardt (born December 25, 1952) is an American theoretical physicist and cosmologist who is currently the Albert Einstein Professor in Science at Princeton University.〔http://www.physics.princeton.edu/~steinh/webbrief/〕 In addition, Steinhardt co-founded and is the current Director of the Princeton Center for Theoretical Science.〔http://pcts.princeton.edu/pcts/faculty_fellows.html〕 ==Academic work== Steinhardt's research has spanned problems in particle physics, astrophysics, cosmology,. condensed matter physics, geoscience and photonics. In cosmology, some of his important contributions include: He is one of the architects of inflationary cosmology which has become an essential part of the big bang theory. He also presented the first example of eternal inflation, which ultimately revealed the multiverse and caused him to doubt the inflation theory he had pioneered. He then became one of the developers of the leading competing alternatives to the big bang, the ekpyrotic and the cyclic theory of the universe. Steinhardt co-authored the first paper to compute the complete imprint of gravitational waves on the spectrum of temperature variations and on the B-mode polarization of the cosmic microwave background. He also co-authored the first paper to show that, based on observations at the time, most of the energy in the universe must be dark energy, enough to cause the universe to expand at an accelerating rate today. Several years later, the conclusion was confirmed by supernova observations. Working with various collaborators, he introduced the concept of quintessential dark energy to further explain the accelerating expansion of the universe. Steinhardt also co-authored the concept of strongly self-interacting dark matter to explain the missing mass of the universe, and to address anomalies previous theories of dark matter were unable to explain. In condensed matter physics and geophysics: Steinhardt and his then-student invented the theoretical concept of quasicrystals, and even introduced the term "quasicrystal" to the lexicon. The two were also the first to correctly identify a puzzling aluminum-magnanese alloy with icosahedral symmetry announced by Dan Shechtman and collaborators in 1984 as the first example of a quasicrystal to be made in a laboratory. The following decade, Steinhardt launched a worldwide search for a quasicrystal formed by a natural geophysical or astrophysical process; his team eventually discovered a candidate in a Florentine museum collection. Their discovery was recognized by the International Mineralogical Association as the first natural quasicrystal, and they accepted the teams' proposed name for it, icosahedrite. Over the next year, disparate clues were pieced together about its origin, finally pointing to a remote mountain range in Chukotka, on Russia's Kamchatka peninsula. Two years later, Steinhardt initiated his first-ever field expedition, and led a team of geologists to the region. As a result of that expedition—and nearly three decades after first inventing the concept of this entirely new form of matter—Steinhardt managed to discover the first quasicrystal formed through a natural process, which his team later proved was part of a 4.5 billion year old meteorite. They also discovered a second quasicrystal named decagonite, along with a new crystalline mineral that was named steinhardtite, in his honor. In photonics: Steinhardt has been an innovator in using quasicrystals and other novel patterns to design photonic materials, including a new class of material called hyperuniform disordered solids. More recently, Steinhardt helped design and fabricate a photonic quasicrystal (the quasicrystal analogue of a photonic crystal) for efficiently trapping and manipulating light in selected wavebands and is one of the leaders developing isotropic photonic materials known as hyperuniform disordered solids (HUDS). Steinhardt and his Princeton colleagues later helped form a company named Etaphase, Inc. to develop commercial applications for those materials. In a ceremony at Perimeter Institute in 2015,〔|url= http://www.perimeterinstitute.ca/videos/psi-ceremony-2015〕 Neil Turok said of Steinhardt: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Paul Steinhardt」の詳細全文を読む スポンサード リンク
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