arXiv subjects

Xuanpu Yang

Publications and source records attributed to Xuanpu Yang.

5 recordsLinked to original sources

arXiv2025

Dissipation-Enhanced Localization in a Disorder-Free $\mathbb{Z}_2$ Lattice Gauge System

The $\mathbb{Z}_2$ lattice gauge model, as the simplest realization of a lattice gauge theory, exhibits rich and unconventional physics. One of its most remarkable features is disorder-free localization, where localization emerges not from explicit quenched disorder but from static background $\mathbb{Z}_2$ gauge charges, leading to persistent memory of the initial state. In this work, we investigate the dissipative dynamics of the $\mathbb{Z}_2$ lattice gauge model by coupling it to a Markovian environment. We find that quantum dissipation can enhance localization: memory of the initial state is retained more robustly under dissipative evolution than under unitary dynamics. This dissipation-induced enhancement of localization persists across a variety of initial states, indicating that the effect is not limited to fine-tuned configurations. Our results demonstrate that dissipation, often associated with decoherence and thermalization, can in fact serve as a powerful tool for stabilizing non-ergodic behavior in gauge-constrained quantum systems.

quant-ph↗

arXiv2025

Robustness of quantum many-body scars in the presence of Markovian bath

A generic closed quantum many-body system will inevitably tend to thermalization, whose local information encoded in the initial state eventually scrambles into the full space, known as quantum ergodicity. A paradigmatic exception in closed quantum systems for strong ergodicity breaking is known as many-body localization, where strong disorder-induced localization prevents the occurrence of thermalization. It is generally recognized that a localized quantum system would be delocalized under dissipation induced by the environment. However, this consequence recently has received challenges where an exotic dissipation-induced localization mechanism is proposed, and transitions between localized and extended phases are found. In this Letter, we promote this mechanism to systems for weak ergodicity breaking hosting quantum many-body scars (QMBS). We find that the system relaxes to a steady state dominated by QMBS, and the dissipative dynamics exhibit dynamic revivals by suitably preparing an initial state. We point out an experimental realization of the controlled dissipation with a cold atomic setup. This makes the signature of ergodicity breaking visible over dissipative dynamics and offers potential possibilities for experimentally preparing stable QMBS with associated coherent dynamics.

cond-mat.dis-nn↗

arXiv2024

Dissipation induced transition between delocalization and localization in the three-dimensional Anderson model

We investigate the probable delocalization-localization transition in open quantum systems with disorder. The disorder can induce localization in isolated quantum systems and it is generally recognized that localization is fragile under the action of dissipations from the external environment due to its interfering nature. Recent work [Y. Liu, et al, Phys. Rev. Lett. 132, 216301 (2024).] found that a one-dimensional quasiperiodic system can be driven into the localization phase by a tailored local dissipation where a dissipation-induced delocalized-localized transition is proposed. Based on this, we consider a more realistic system and show that a dissipation-induced transition between delocalization and localization appears in the three-dimensional (3D) Anderson model. By tuning local dissipative operators acting on nearest neighboring sites, we find that the system can relax to localized states dominated steady state instead of the choice of initial conditions and dissipation strengths. Moreover, we can also realize a delocalized states predominated steady-state from a localized initial state by using a kind of dissipation operators acting on next nearest neighboring sites. Our results enrich the applicability of dissipation-induced localization and identify the transition between delocalized and localized phases in 3D disordered systems.

cond-mat.dis-nn↗

arXiv2024

Dissipation induced ergodic-nonergodic transitions in finite-height mosaic Wannier-Stark lattices

Recent research has observed the occurrence of pseudo-mobility edge (ME) within a modulated mosaic model incorporating the Wannier-Stark potential. This pseudo-ME, which signifies the critical energy that distinguishes between ergodic and weakly ergodic, or weakly ergodic and nonergodic states, is a crucial concept in comprehending the transport and localization phenomena in Wannier-Stark systems. Here we investigate the influence of dissipation on a finite-height mosaic Wannier-Stark lattice that features such pseudo-MEs by computing the steady state density matrix. Our findings indicate that particular dissipation can steer the system into specific states, regardless of its initial state, predominantly characterized by either ergodic or nonergodic states. This suggests that dissipation can be harnessed as a novel method for inducing transitions between these states and manipulating particle localization behaviors in disorder-free systems.

cond-mat.mes-hall↗

arXiv2024

Liouvillian skin effect in a one-dimensional open many-body quantum system with generalized boundary conditions

Non-Hermitian skin effect (NHSE), namely that eigenstates of non-Hermitian Hamiltonains are localized at one boundary in the open boundary condition, attracts great interest recently.In this paper, we investigate the skin effect in one-dimensional dissipative quantum many-body systems, which we call the Liouvillian skin effect (LSE). We rigorously identify the existence of LSE for generalized boundary conditions by solving the Liouvillian superoperator of an exactly solvable model with the advantage of Bethe ansatz. The LSE is sensitive to boundary conditions where the signature is reflected in eigenfunctions of the system. We confirm that the LSE is fragile to a tiny co-flow boundary hopping with non-Hermitian current but can survive for a counter-flow boundary hopping in the thermodynamic limit. Our work provides a prototypical example of exactly solvable dissipative quantum many-body lattice systems exhibiting LSE for generalized boundary conditions. It can be further extended to other integrable open quantum many-body models.

quant-ph↗