2026/07/24 by Jian-Song Pan, Xiaofan Zhou, Wei Yi
#cond-mat.quant-gas #cond-mat.str-el #quant-ph
The destruction of Aharonov-Bohm (AB) caging by interaction and the emergence of interaction-induced chiral currents in flux lattices are two paradigmatic examples of interaction-driven quantum transport. While various mechanisms, such as bound-state formation and chiral spectral imbalance, have been proposed, a unifying physical picture remains elusive. Here, we employ the concept of evolution-path symmetry (EPS) and its interaction-induced breaking as a framework to understand interaction-induced delocalization in flux lattices. EPS is defined as the invariance of a path's contribution under combined geometric and phase transformations. We demonstrate that in a π-flux rhombic lattice, interactions break the EPS present in the non-interacting limit by modifying the phase accumulation of many-body paths, thereby lifting the destructive interference responsible for AB caging. Furthermore, we apply this framework to explain interaction-induced chiral transport in flux ladders, where interactions break the phase relationship between symmetric paths, leading to a non-vanishing chiral current. Our work establishes EPS as a powerful tool for understanding transport phenomena beyond conventional eigenstate analysis.