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→Dynamical symmetry breaking
}}</ref> It was shown, in the presence of a symmetric Hamiltonian, and in the limit of infinite volume, the system spontaneously adopts a chiral configuration — i.e., breaks [[mirror plane]] [[symmetry]].
}}</ref> It was shown, in the presence of a symmetric Hamiltonian, and in the limit of infinite volume, the system spontaneously adopts a chiral configuration — i.e., breaks [[mirror plane]] [[symmetry]].
===Dynamical symmetry breaking===
===Dynamical symmetry breaking 动力学对称性破缺===
Dynamical symmetry breaking (DSB) is a special form of spontaneous symmetry breaking in which the ground state of the system has reduced symmetry properties compared to its theoretical description (i.e., [[Lagrangian (field theory)|Lagrangian]]).
Dynamical symmetry breaking (DSB) is a special form of spontaneous symmetry breaking in which the ground state of the system has reduced symmetry properties compared to its theoretical description (i.e., [[Lagrangian (field theory)|Lagrangian]]).
动力学对称性破缺(DSB)是自发对称性破缺的一种特殊形式，在这种情况下，系统的基态比理论描述(例如拉格朗日量)的对称性降低。
Dynamical breaking of a global symmetry is a spontaneous symmetry breaking, which happens not at the (classical) tree level (i.e., at the level of the bare action), but due to quantum corrections (i.e., at the level of the [[effective action]]).
Dynamical breaking of a global symmetry is a spontaneous symmetry breaking, which happens not at the (classical) tree level (i.e., at the level of the bare action), but due to quantum corrections (i.e., at the level of the [[effective action]]).
全局对称性的动力学破缺是自发对称性破缺，它不是发生在(经典)树的水平(例如在bare作用的水平)，而是由于量子修正(例如在有效作用的水平)。
Dynamical breaking of a gauge symmetry {{ref|note1}} is subtler. In the conventional spontaneous gauge symmetry breaking, there exists an unstable [[Higgs particle]] in the theory, which drives the vacuum to a symmetry-broken phase. (See, for example, [[electroweak interaction]].) In dynamical gauge symmetry breaking, however, no unstable Higgs particle operates in the theory, but the bound states of the system itself provide the unstable fields that render the phase transition. For example, Bardeen, Hill, and Lindner published a paper that attempts to replace the conventional [[Higgs mechanism]] in the [[standard model]] by a DSB that is driven by a bound state of top-antitop quarks. (Such models, in which a composite particle plays the role of the Higgs boson, are often referred to as "Composite Higgs models".)<ref>
Dynamical breaking of a gauge symmetry {{ref|note1}} is subtler. In the conventional spontaneous gauge symmetry breaking, there exists an unstable [[Higgs particle]] in the theory, which drives the vacuum to a symmetry-broken phase. (See, for example, [[electroweak interaction]].) In dynamical gauge symmetry breaking, however, no unstable Higgs particle operates in the theory, but the bound states of the system itself provide the unstable fields that render the phase transition. For example, Bardeen, Hill, and Lindner published a paper that attempts to replace the conventional [[Higgs mechanism]] in the [[standard model]] by a DSB that is driven by a bound state of top-antitop quarks. (Such models, in which a composite particle plays the role of the Higgs boson, are often referred to as "Composite Higgs models".)<ref>
|author1-link=William A. Bardeen
|author1-link=William A. Bardeen
}}</ref> Dynamical breaking of gauge symmetries is often due to creation of a [[fermionic condensate]] — e.g., the [[quark condensate]], which is connected to the [[Chiral symmetry breaking|dynamical breaking of chiral symmetry]] in [[quantum chromodynamics]]. Conventional [[superconductivity]] is the paradigmatic example from the condensed matter side, where phonon-mediated attractions lead electrons to become bound in pairs and then condense, thereby breaking the electromagnetic gauge symmetry.
}}</ref> Dynamical breaking of gauge symmetries is often due to creation of a [[fermionic condensate]] — e.g., the [[quark condensate]], which is connected to the [[Chiral symmetry breaking|dynamical breaking of chiral symmetry]] in [[quantum chromodynamics]]. Conventional [[superconductivity]] is the paradigmatic example from the condensed matter side, where phonon-mediated attractions lead electrons to become bound in pairs and then condense, thereby breaking the electromagnetic gauge symmetry.
规范对称性动力学破缺更加微妙。在常规规范对称自发破缺理论中，存在一个不稳定的希格斯粒子，希格斯粒子驱动真空进入对称破缺相。(例如，参见弱电相互作用。)然而，在规范对称性动力学破缺中，不存在不稳定的希格斯粒子，但系统本身的束缚态提供了导致相变的不稳定场。例如，巴丁、希尔和林德纳发表了一篇论文，试图用一个由顶-反顶夸克束缚状态驱动的DSB来取代标准模型中的传统希格斯机制。(在这种模型中，复合粒子扮演希格斯玻色子的角色，通常被称为“复合希格斯模型”。)规范对称性动力学破缺通常是由于费米凝聚的产生，例如夸克凝聚，它与量子色动力学中手性对称的动力学破缺有关。传统的超导性是凝聚态物质方面的典型例子，声子的吸引导致电子成对结合然后凝聚，从而打破电磁规范对称性。
==Generalisation and technical usage==
==Generalisation and technical usage==