论文标题
计算异常的统一操作员
Gauging anomalous unitary operators
论文作者
论文摘要
静态散装拓扑阶段的边界理论被妨碍，因为它们不能自行实现为孤立的系统。障碍物可以通过量子异常来量化/特征，特别是当存在全局对称性时。同样，拓扑浮雕的演变可以在边界上实现阻塞的统一操作员。在本文中，我们通过使用量子异常讨论了此类障碍物的表征。作为一个特殊的例子，我们在一个和两个空间维度中讨论了时间反转对称边界统一运算符，当我们评估所谓的Kubo-Martin-Schwinger（KMS）对称性时，异常出现。我们还讨论了在奇数空间维度中，在奇数空间维度中，在构成u（1）对称对称性和离散对称的粒子数之间的混合异常，例如C和CP。
Boundary theories of static bulk topological phases of matter are obstructed in the sense that they cannot be realized on their own as isolated systems. The obstruction can be quantified/characterized by quantum anomalies, in particular when there is a global symmetry. Similarly, topological Floquet evolutions can realize obstructed unitary operators at their boundaries. In this paper, we discuss the characterization of such obstructions by using quantum anomalies. As a particular example, we discuss time-reversal symmetric boundary unitary operators in one and two spatial dimensions, where the anomaly emerges as we gauge the so-called Kubo-Martin-Schwinger (KMS) symmetry. We also discuss mixed anomalies between particle number conserving U(1) symmetry and discrete symmetries, such as C and CP, for unitary operators in odd spatial dimensions that can be realized at the boundaries of topological Floquet systems in even spatial dimensions.
