Stability of PPT in equilibrium states

TL;DR

This paper demonstrates that the positive partial transpose property of equilibrium states in infinite-dimensional quantum systems remains stable under small or high-temperature perturbations of the Hamiltonian, using spectral perturbation theory.

Contribution

It introduces a spectral perturbation approach to prove the stability of PPT in infinite-dimensional equilibrium states under bounded Hamiltonian perturbations.

Findings

PPT stability holds at high temperatures or small perturbations

Spectral perturbation theory is effective for analyzing PPT stability

Results apply to infinite-dimensional quantum systems

Abstract

We use simple spectral perturbation theory to show that the positive partial transpose property is stable under bounded perturbations of the Hamiltonian, for equilibrium states in infinite dimensions. The result holds provided the temperature is high enough, or equivalently, provided the perturbation is small enough.