Noise-Induced Topology in Chiral Quantum Walks

arXiv:2611.05471v1 Announce Type: new Abstract: Noise typically destroys quantum coherence and washes out transport phenomena that rely on interference. Chiral quantum walks are a case in point: a particle hopping on a lattice threaded by a magnetic flux can spread asymmetrically due to interference between paths, an asymmetry that noise is expected to erase. Remarkably, we find that the most ubiquitous noise -- random fluctuations of on-site energies (dephasing) -- instead renders this asymmetry topologically robust. The density profile develops a skewness that grows in time while its center stays fixed, and in a finite chain the late-time relaxation modes pile up at one edge: a skin effect lacking the drift of conventional non-Hermitian skin effects.