We study a single-particle Lindblad lattice in which nonreciprocal incoherent hopping is combined with a tunable coherent boundary link. The link changes the Hamiltonian boundary condition while the incoherent jump rates are kept fixed, so it does not directly alter the diagonal population generator. Its effect on the Liouvillian gap comes from population-coherence-population feedback: the Hamiltonian couples populations to damped coherences, and eliminating those coherences produces a frequency-dependent self-energy for the slow population branch. For the periodic reference system, where translation symmetry is imposed on both the Hamiltonian and the dissipator, we derive an exact fixed-momentum reduction, a scalar secular equation for the population-connected branch, and the associated hydrodynamic drift and coherence-corrected diffusion. For open finite lattices, exact diagonalization and sparse near-zero eigensolvers show that the coherent boundary link can enhance or suppress the gap in one dimension and produce geometry-dependent responses in two dimensions. We also show that an observed relaxation scale can differ from $1/Δ_{\mathcal L}$ when the gap family has weak visibility in the chosen perturbation and observable. The periodic construction gives exact analytical benchmarks, while finite-size simulations in one and two dimensions demonstrate how the same coherence-mediated mechanism controls open-boundary gaps and observable relaxation.
We study a single-particle Lindblad lattice in which nonreciprocal incoherent hopping is combined with a tunable coherent boundary link. The link changes the Hamiltonian boundary condition while the incoherent jump rates are kept fixed, so it does not directly alter the diagonal population generator. Its effect on the Liouvillian gap comes from population-coherence-population feedback: the Hamiltonian couples populations to damped coherences, and eliminating those coherences produces a frequency-dependent self-energy for the slow population branch. For the periodic reference system, where translation symmetry is imposed on both the Hamiltonian and the dissipator, we derive an exact fixed-momentum reduction, a scalar secular equation for the population-connected branch, and the associated hydrodynamic drift and coherence-corrected diffusion. For open finite lattices, exact diagonalization and sparse near-zero eigensolvers show that the coherent boundary link can enhance or suppress the gap in one dimension and produce geometry-dependent responses in two dimensions. We also show that an observed relaxation scale can differ from 1/ΔL when the gap family has weak visibility in the chosen perturbation and observable. The periodic construction gives exact analytical benchmarks, while finite-size simulations in one and two dimensions demonstrate how the same coherence-mediated mechanism controls open-boundary gaps and observable relaxation.
In open quantum lattice systems, changing the boundary condition would appear to alter both the steady state and the nonzero Liouvillian spectrum. Here we show that boundary conditions can be used to control relaxation without changing the reduced steady state. In a disordered dissipative quantum link chain, the steady state is determined by an accumulated field defined by link-resolved dissipative disorder, and a gauge-generated transformation built from this field gives exact symmetry-resolved steady states with nonuniform, accumulated-field-dependent reduced matter occupations. We then construct a reciprocal cyclic boundary condition that preserves these matter occupations while changing the nonzero Liouvillian spectrum. Consequently, open and cyclic chains relax to the same reduced matter steady-occupation profile with different Liouvillian gaps with the cyclic closure accelerating relaxation. In the strong-dissipation limit, this relaxation difference can be reduced to a spectral comparison of effective exclusion processes with open and cyclic boundaries.
We develop a microscopic theory for how slow Liouvillian sectors are selected in an open correlated lattice. The starting point is not a postulated non-Hermitian band, but a local interacting resonance between an on-site doublon and a branch-resolved nearest-neighbor bond. This resonance defines a composite shell orbital whose doublon weight controls reservoir visibility and whose mixed doublon-bond character controls shell mobility. Projecting the microscopic hopping onto the selected shell yields a branch-selective dimerized channel. In the dilute regime, a boundary doublon-loss channel yields an exponentially slow edge-memory pole through a Zeno-type return. At the shell-critical point, the edge pole is replaced by a near-zero standing-wave doublet with an algebraic coherent spacing. At finite shell filling, the same local shell becomes density dressed. A number-conserving phase-locking jump removes a bright mismatch sector, leaving defects as the asymptotic slow variables and producing a diffusive finite-size gap. We derive the local shell, the projected branch topology, the edge-memory law, the shell-critical doublet, the density-dressed shell Hamiltonian, and the defect generator within one Schur-projection framework. The resulting mechanism identifies the reservoir-engineered fast block as the selector of the observable slow sector, while the microscopic parent shell remains fixed.
We unveil a quantum Pontus-Mpemba effect enabled by the Liouvillian skin effect in a dissipative tight-binding chain with asymmetric incoherent hopping and coherent boundary coupling. The skin effect, induced by non-reciprocal dissipation, localizes relaxation modes near the system boundaries and gives rise to non-orthogonal spectral geometry. While such non-normality is often linked to slow relaxation, we show that it can instead accelerate relaxation through a two-step protocol - realizing a quantum Pontus-Mpemba effect. Specifically, we consider a one-dimensional open chain with coherent hopping J, asymmetric incoherent hoppings JR=JL, and a controllable end-to-end coupling ε. For ε=0, the system exhibits the Liouvillian skin effect, with left and right eigenmodes localized at opposite edges. We compare two relaxation protocols toward the same stationary state: (i) a direct relaxation with ε=0, and (ii) a two-step (Pontus) protocol where a brief coherent evolution transfers the excitation across the lattice before relaxation. Although both share the same asymptotic decay rate, the two-step protocol relaxes significantly faster due to its reduced overlap with the slow boundary-localized Liouvillian mode. The effect disappears when JR=JL, i.e., when the skin effect vanishes. Our results reveal a clear connection between boundary-induced non-normality and protocol-dependent relaxation acceleration, suggesting new routes for controlling dissipation and transient dynamics in open quantum systems.
Open quantum systems far from thermal equilibrium can exhibit remarkable physical phenomena including topological properties without a direct equilibrium counterpart. Along these lines, in periodically driven-dissipative systems within the effective non-Hermitian (NH) Hamiltonian approximation spectral winding numbers have been linked to intriguing nonreciprocal transport properties. Here, going beyond an NH Hamiltonian description, we introduce and study a microscopic lattice model of a driven open quantum system described by a Markovian quantum master equation, which exhibits the mentioned spectral winding within an NH approximation. By encompassing quantum jump processes in the topological analysis, we uncover a distinct \emph{jump-induced} topological phase, which qualitatively corresponds to the richer nonreciprocal transport properties of the fully quantum model. In addition, we find that the NH skin effect, i.e., the accumulation of a macroscopic number of eigenstates at one end of the system, is already visible in the transient dynamics even for systems with periodic boundary conditions. Our results exemplify the subtle correspondence between NH topological properties and physical manifestations of Liouvillian topological properties in open quantum systems, thus providing a theoretical framework towards understanding unidirectional transport in quantum dissipative Floquet dynamics.
Abstract Understanding how dissipation affects quantum many-body dynamics is crucial for quantum information processing, yet explicit quantitative predictions remain scarce. While closed quantum systems with spectral gaps exhibit robust dynamical properties, the transition to open systems governed by Lindblad dynamics has lacked constructive bounds relating Hamiltonian gaps to Liouvillian relaxation timescales. Scientific novelty. We derive the first explicit, parameter-dependent bound connecting a constructive Hamiltonian gap to the Liouvillian spectral gap in weakly dissipative quantum lattice systems. Starting from a frustration-free Hamiltonian with Nemirovsky gate gap Δgate = m0 − 2zgVmax > 0 and adding local Lindblad dissipation with strength γ ≪ Δgate, we prove that the Liouvillian gap satisfies ΛL ≥ Δgate − 2π·z·d·γ·Vdiss with explicit constant C = 2π, where z is the lattice coordination number, d is the number of dissipators per site, and Vdiss bounds the dissipator norms. This inequality provides quantitative control over open-system dynamics directly from microscopic parameters, enabling predictions for finite systems without asymptotic limits. We further establish a dissipative spectral weight bound WAdiss(E) ≤ K(A)·min(1, E/Λeff), where Λeff = Δgate − O(γ) characterizes the effective gap reduction. This directly yields the relaxation time lower bound τrelax ≥ ℏ/Λeff, with immediate applications to Rydberg atom arrays, trapped ions, and neutral atom quantum processors. Our results bridge constructive Hamiltonian spectral theory and open quantum dynamics, providing experimentalists with concrete design criteria for quantum gate timing, many-body scar lifetimes, and error correction protocols. Unlike previous existence theorems, our bounds are fully constructive, perturbative, and applicable to experimentally relevant parameter regimes. Keywords: Open quantum systems, Liouvillian gap, spectral bounds, Lindblad dynamics, dissipative quantum many-body systems, relaxation times, quantum simulators, Rydberg atoms, constructive quantum mechanics
Can superconducting order be engineered as a robust attractor of open-system dynamics in strongly correlated systems? We demonstrate this possibility by proposing a minimal dissipation-engineering protocol for the particle-hole symmetric Hubbard model. By applying a rotated quantum jump operator, specifically a locally transformed η-pair lowering operator, on a single lattice site only, we show that the Lindblad evolution autonomously pumps the system from the vacuum into a nonequilibrium steady state (NESS) exhibiting macroscopic η-pair off-diagonal long-range order (ODLRO). Crucially, this local-to-global synchronization stands in stark contrast to schemes reliant on spatially extensive reservoirs: here, a single local dissipative seed suffices to establish long-range coherence across the entire interacting lattice system. We elucidate the underlying mechanism via three core features: local dark-state selection, the controlled elimination of off-manifold excursions induced by hopping, and a Liouvillian invariant-subspace structure that yields an attractive fixed point with a finite dissipative gap. Furthermore, we systematically classify the stability of this NESS with respect to static disorder, and identify a wide regime in which the superconducting attractor remains robust against Hamiltonian perturbations that preserve the effective subspace structure. We also pinpoint specific perturbations that directly cause dephasing of the -pseudospin coherence and suppress ODLRO. These findings open up a disorder-tolerant pathway for stabilizing superconducting order as a non-thermal attractor through minimal local quantum-jump control.