Landau ordering phase transitions beyond the Landau paradigm
Landau ordering phase transitions beyond the Landau paradigm
复制标题
DOI：
10.1103/physrevresearch.2.023031
复制
发表时间：
2019-10
影响因子：
4.2
通讯作者：
Zhen Bi;E. Lake;T. Senthil
中科院分区：
文献类型：
--
作者：
Zhen Bi;E. Lake;T. Senthil
与自发破缺对称性的发生相关的连续相变被认为是由波动序参量的Landau-Ginzburg-Wilson-Fisher理论成功描述的。在这项工作中，我们表明，这种过渡可以承认新的普遍性类，不能理解的理论序参数波动。我们明确地证明了连续的时间反演对称性破缺量子相变的3 +1$-D玻色子系统所描述的临界理论表示在一个deconfined规范理论与无质量狄拉克费米子，而不是波动的伊辛序参数。我们称这种相变为“超越朗道描述的朗道相变”（LBL）。我们的例子的一个关键特征是，LBL不动点的稳定性需要一个至关重要的全局对称性，这是非异常的，不间断的，并在整个相图中呈现不对称保护的拓扑相位。尽管如此，有基本的临界波动的相变，变换投影在这个对称群。我们还构建了其他新的量子临界现象的例子，特别是一个连续的朗道禁止解除限制的临界点之间的两个朗道允许的阶段在$3+1$-D。
Continuous phase transitions associated with the onset of a spontaneously broken symmetry are thought to be successfully described by the Landau-Ginzburg-Wilson-Fisher theory of fluctuating order parameters. In this work we show that such transitions can admit new universality classes which cannot be understood in terms of a theory of order parameter fluctuations. We explicitly demonstrate continuous time reversal symmetry breaking quantum phase transitions of $3+1$-D bosonic systems described by critical theories expressed in terms of a deconfined gauge theory with massless Dirac fermions instead of the fluctuating Ising order parameter. We dub such phase transitions "Landau transitions beyond Landau description" (LBL). A key feature of our examples is that the stability of the LBL fixed points requires a crucial global symmetry, which is non-anomalous, unbroken, and renders no symmetry protected topological phase throughout the phase diagram. Despite this, there are elementary critical fluctuations of the phase transition that transform projectively under this symmetry group. We also construct examples of other novel quantum critical phenomena, notably a continuous Landau-forbidden deconfined critical point between two Landau-allowed phases in $3+1$-D.