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In physics, asymptotic freedom is a property of some gauge theories that causes bonds between particles to become asymptotically weaker as energy increases and distance decreases. Asymptotic freedom is a feature of quantum chromodynamics (QCD), the quantum field theory of the nuclear interaction between quarks and gluons, the fundamental constituents of nuclear matter. Quarks interact weakly at high energies, allowing perturbative calculations by DGLAP of cross sections in deep inelastic processes of particle physics; and strongly at low energies, preventing the unbinding of baryons (like protons or neutrons with three quarks) or mesons (like pions with two quarks), the composite particles of nuclear matter. Asymptotic freedom was rediscovered and described in 1973 by Frank Wilczek and David Gross,〔 〕 and independently by David Politzer in the same year.〔 〕 All three shared the Nobel Prize in physics in 2004. == Discovery == Asymptotic freedom was described and published in 1973 by David Gross and Frank Wilczek, and also by David Politzer. Although these authors were the first to understand the physical relevance to the strong interactions, in 1965 V.S. Vanyashin and M.V. Terent'ev discovered asymptotic freedom in QED with charged vector field〔 〕 and in 1969 Iosif Khriplovich in the SU(2) gauge theory.〔 〕 Gerardus 't Hooft in 1972 also noted the effect but did not publish it.〔 〕 For their discovery, Gross, Wilczek and Politzer were awarded the Nobel Prize in Physics in 2004. The discovery was instrumental in rehabilitating quantum field theory. Prior to 1973, many theorists suspected that field theory was fundamentally inconsistent because the interactions become infinitely strong at short distances. This phenomenon is usually called a Landau pole, and it defines the smallest length scale that a theory can describe. This problem was discovered in field theories of interacting scalars and spinors, including quantum electrodynamics, and Lehman positivity led many to suspect that it is unavoidable.〔 〕 Asymptotically free theories become weak at short distances, there is no Landau pole, and these quantum field theories are believed to be completely consistent down to any length scale. While the Standard Model is not entirely asymptotically free, in practice the Landau pole can only be a problem when thinking about the Higgs boson. This fact is important as Quantum triviality can be used to bound or even ''predict'' parameters such as the Higgs boson mass. This can also lead to a predictable Higgs mass in asymptotic safety scenarios. The other interactions are so weak that any inconsistency can only arise at distances shorter than the Planck length, where a field theory description might be inadequate anyway. 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「asymptotic freedom」の詳細全文を読む スポンサード リンク
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