Dynamical ${\mathbb{Z}}_2$ Skin Channels and Effective Loschmidt Cusps

Abstract

We analytically describe the dynamically separated ${\mathbb{Z}}_2$ skin channels (wavepacket evolutions) under periodic boundary condition (PBC) in non-Hermitian systems with anomalous time-reversal symmetry (ATRS), by combining the semiclassical worldline perspective with an enhanced understanding of skin effects. These channels, tied to the initial state and relevant symmetries, exhibit individually exponential-dominated time evolution in momentum space, where their amplitude maxima evolve toward the dominant momenta. In real space, their center of masses (COMs) circulate around the one-dimensional (1D) chain, tracing semiclassical worldlines. Such circulations imply quantum revivals and effective Loschmidt cusps (LCs), with the latter showing scale-dependent behavior, a feature distinct from conventional dynamical quantum phase transitions. This work extends our previous findings on worldline windings and the winding-control mechanism to the ${\mathbb{Z}}_2$ skin effects, confirming that the core physics is shared with the ordinary skin effect.

arXiv comment18 pages, 9 figures