Di Ventra Massimiliano, Pershin Yuriy V, Chien Chih-Chun
Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA.
Phys Rev Lett. 2022 Mar 4;128(9):097701. doi: 10.1103/PhysRevLett.128.097701.
Custodial symmetries are common in the standard model of particle physics. They arise when quantum corrections to a parameter are proportional to the parameter itself. Here, we show that a custodial symmetry of the chiral type is also present in a classical Su-Schrieffer-Heeger (SSH) electrical circuit with memory. In the absence of memory, the SSH circuit supports a symmetry-protected topological edge state. Memory induces nonlinearities that break chiral symmetry explicitly and spread the state across the circuit. However, the resulting state is still protected against perturbations by the ensuing custodial chiral symmetry. These predictions can be verified experimentally and demonstrate the interplay between symmetry and memory.
守恒对称性在粒子物理标准模型中很常见。当对一个参数的量子修正与该参数本身成比例时，它们就会出现。在这里，我们表明具有记忆功能的经典苏-施里弗-黑格（SSH）电路中也存在手征型的守恒对称性。在没有记忆的情况下，SSH电路支持一种对称性保护的拓扑边缘态。记忆会引入非线性，从而明确地破坏手征对称性，并使该状态在整个电路中扩展。然而，由此产生的状态仍然受到随之而来的守恒手征对称性的保护，免受微扰影响。这些预测可以通过实验验证，并证明了对称性与记忆之间的相互作用。
