# Perturbation theory of KMS states

## TL;DR

This paper extends a recent perturbation formula for equilibrium states to a broader class of KMS states within general $W^*$-dynamical systems, enhancing the theoretical understanding of quantum statistical mechanics.

## Contribution

It generalizes Hastings' perturbation formula to KMS states in $W^*$-dynamical systems, broadening its applicability.

## Key findings

- Extended perturbation formula to KMS states
- Applicable to general $W^*$-dynamical systems
- Provides new tools for quantum statistical mechanics

## Abstract

We extend the new perturbation formula of equilibrium states by Hastings to KMS states of general $W^*$-dynamical systems.