# Shortcut to Equilibration of an Open Quantum System

## TL;DR

This paper introduces a control protocol called Shortcut to Equilibration that rapidly drives an open quantum system to its equilibrium state, significantly improving thermalization speed and accuracy.

## Contribution

The paper proposes a reverse-engineered, non-unitary control method to accelerate the relaxation process of open quantum systems towards equilibrium.

## Key findings

- Achieves three orders of magnitude improvement in thermalization accuracy for short protocols
- Demonstrates effectiveness on a particle in a harmonic well
- Provides a practical approach to rapid quantum state equilibration

## Abstract

We present a procedure to accelerate the relaxation of an open quantum system towards its equilibrium state. The control protocol, termed Shortcut to Equilibration, is obtained by reverse-engineering the non-adiabatic master equation. This is a non-unitary control task aimed at rapidly changing the entropy of the system. Such a protocol serves as a shortcut to an abrupt change in the Hamiltonian, i.e., a quench. As an example, we study the thermalization of a particle in a harmonic well. We observe that for short protocols there is a three orders of magnitude improvement in accuracy.