论文标题

保形理论的热顺序

Thermal Order in Conformal Theories

论文作者

Chai, Noam, Chaudhuri, Soumyadeep, Choi, Changha, Komargodski, Zohar, Rabinovici, Eliezer, Smolkin, Michael

论文摘要

人们普遍期望,在足够高的温度下始终会丢失,例如磁铁松散其铁磁特性。我们提出了一个问题,即在$ d $空间维度中的量子场理论中是否总是这样。更具体地说,可以询问是否存在在任意有限温度下打破一些全局对称性的关键点(CFT)。最熟悉的CFT不会在有限温度下表现出对称性破裂,此外,在ADS/CFT对应关系的背景下,有限温度下的临界点由一个不负荷的黑色棕褐色描述,该黑色棕褐色遵守无发品定理。但是,我们表明存在在任意有限温度下破裂的内部对称性的CFT。我们的主要示例是一个向量模型,我们在Epsilon扩展和任意等级以及较大的等级限制(和任意维度)中研究。矢量模型的较大等级极限显示在有限温度下真空吸尘器的模量空间和变形的模量空间。确定了适当的Nambu-Goldstone玻色子,包括Dilaton样粒子。使用这些工具,我们为有限的小$ε$在有限温度下建立对称性破裂。我们还证明,描述了一些最常见的量子磁体的大量其他固定点确实是预期的,并且不会在有限温度下打破任何全球对称性。我们讨论了有限温度对称性破坏本地操作员的后果。最后,我们提出了一类固定点,这些固定点似乎是有限温度对称性破坏$ d = 2 $的候选者。

It is widely expected that at sufficiently high temperatures order is always lost, e.g. magnets loose their ferromagnetic properties. We pose the question of whether this is always the case in the context of quantum field theory in $d$ space dimensions. More concretely, one can ask whether there exist critical points (CFTs) which break some global symmetry at arbitrary finite temperature. The most familiar CFTs do not exhibit symmetry breaking at finite temperature, and moreover, in the context of the AdS/CFT correspondence, critical points at finite temperature are described by an uncharged black brane which obeys a no-hair theorem. Yet, we show that there exist CFTs which have some of their internal symmetries broken at arbitrary finite temperature. Our main example is a vector model which we study both in the epsilon expansion and arbitrary rank as well as the large rank limit (and arbitrary dimension). The large rank limit of the vector model displays a conformal manifold, a moduli space of vacua, and a deformed moduli space of vacua at finite temperature. The appropriate Nambu-Goldstone bosons including the dilaton-like particle are identified. Using these tools we establish symmetry breaking at finite temperature for finite small $ε$. We also prove that a large class of other fixed points, which describe some of the most common quantum magnets, indeed behave as expected and do not break any global symmetry at finite temperature. We discuss some of the consequences of finite temperature symmetry breaking for the spectrum of local operators. Finally, we propose a class of fixed points which appear to be possible candidates for finite temperature symmetry breaking in $d=2$.

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