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arXiv · 2406.03026

Dynamical topology of chiral and nonreciprocal state transfers in a non-Hermitian quantum system

Pengfei Lu·Yang Liu·Qifeng Lao·Teng Liu·Xinxin Rao·Ji Bian·Hao Wu·Feng Zhu·Le Luo
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Abstract

The fundamental concept underlying topological phenomena posits the geometric phase associated with eigenstates. In contrast to this prevailing notion, theoretical studies on time-varying Hamiltonians allow for a new type of topological phenomenon, known as topological dynamics, where the evolution process allows a hidden topological invariant associated with continuous flows. To validate this conjecture, we study topological chiral and nonreciprocal dynamics by encircling the exceptional points (EPs) of non-Hermitian Hamiltonians in a trapped ion system. These dynamics are topologically robust against external perturbations even in the presence dissipation-induced nonadiabatic processes. Our findings indicate that they are protected by dynamical vorticity -- an emerging topological invariant associated with the energy dispersion of non-Hermitian band structures in a parallel transported eigenbasis. The symmetry breaking and other key features of topological dynamics are directly observed through quantum state tomography. Our results mark a significant step towards exploring topological properties of open quantum systems.

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Pengfei Lu, Yang Liu, Qifeng Lao, Teng Liu, Xinxin Rao, Ji Bian, Hao Wu, Feng Zhu, Le Luo. 2024-06-05. Dynamical topology of chiral and nonreciprocal state transfers in a non-Hermitian quantum system. https://arxiv.org/abs/2406.03026

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