Delocalization of skin steady states

TL;DR

This paper investigates how increasing interchain coupling causes delocalization of skin steady states in non-Hermitian systems, revealing a critical Liouvillian skin effect and a transition from area law to logarithmic entanglement scaling.

Contribution

It introduces a model demonstrating the delocalization of skin steady states and uncovers a critical Liouvillian skin effect along with entanglement transitions beyond the quantum Zeno effect.

Findings

Skin steady states become delocalized with increased coupling.

Liouvillian gap scaling shifts from constant to inverse square with system size.

Entanglement scaling transitions from area law to logarithmic law.

Abstract

The skin effect, characterized by the tendency of particles to accumulate at the boundaries, has been extensively studied in non-Hermitian systems. In this work, we propose an intuitive Lindbladian composed of two chains with reversed skin localization. The skin steady state is gradually delocalized as the interchain coupling increases. In the single-body scenario, it corresponds to a shift in the scaling of the Liouvillian gap $\Delta$ from $\Delta \propto N^0$ to $\Delta \propto N^{-2}$. Notably, exact diagonalization results reveal a system-size sensitivity of the single-particle Liouvillian spectrum, inherited from the non-Hermitian effective Hamiltonian's system-size sensitivity. We predict that even an arbitrarily small coupling will induce dramatic changes in the Liouvillian spectrum and steady state in the thermodynamic limit, a phenomenon we term the critical Liouvillian skin effect. Additionally, in the many-body scenario, by employing the stochastic Schr\"odinger equation to unravel the Lindblad master equation, it is revealed that the scaling behavior of steady-state entanglement changes from the area law to the logarithmic law. This work demonstrates the delocalization of both single-body and many-body skin steady states, introducing a novel mechanism for inducing entanglement transitions beyond the quantum Zeno effect.