A positive tensor network approach for simulating open quantum many-body systems

TL;DR

This paper introduces a tensor network method for simulating open quantum many-body systems that preserves positivity and controls approximation errors, enabling accurate analysis of dissipative quantum dynamics.

Contribution

A new tensor network approach using locally purified states for efficient and positive-preserving simulation of open quantum systems in one dimension.

Findings

Successfully simulates stationary and transient states

Handles systems from few to many bodies

Overcomes limitations of previous methods

Abstract

Open many-body quantum systems play an important role in quantum optics and condensed-matter physics, and capture phenomena like transport, interplay between Hamiltonian and incoherent dynamics, and topological order generated by dissipation. We introduce a versatile and practical method to numerically simulate one-dimensional open quantum many-body dynamics using tensor networks. It is based on representing mixed quantum states in a locally purified form, which guarantees that positivity is preserved at all times. Moreover, the approximation error is controlled with respect to the trace norm. Hence, this scheme overcomes various obstacles of the known numerical open-system evolution schemes. To exemplify the functioning of the approach, we study both stationary states and transient dissipative behaviour, for various open quantum systems ranging from few to many bodies.