Simulating Feedback Cooling of Incoherent Quantum Mixtures

TL;DR

This paper introduces a scalable phase-space simulation method for quantum measurement and control, successfully demonstrating feedback cooling of a thermal quantum ensemble to degeneracy, and highlighting its broad applicability.

Contribution

A new scalable simulation approach based on the Truncated Wigner Approximation for quantum feedback control, enabling multi-mode simulations of measurement-based cooling.

Findings

First simulation of feedback cooling of a quasi-1D thermal ensemble to quantum degeneracy.

Demonstrates multi-mode scalability of the proposed simulation method.

Benchmarking against particle-filter methods shows advantages in efficiency and scalability.

Abstract

We develop a new approach for efficient and scalable simulations of measurement and control of quantum systems built upon existing phase-space methods, namely the Truncated Wigner Approximation (TWA). We benchmark against existing particle-filter methods by simulating measurement based feedback cooling in a two-mode system, whose low-dimensional nature permits a computation of an exact solution. The advantage of our method is multi-mode scalability, which we demonstrate through the first successful simulation of measurement-based feedback cooling of an incoherent quasi-1D thermal ensemble to quantum degeneracy. As the underlying principle of our approach exploits a general correspondence between measurement and coherent feedback, we anticipate it is also applicable across a broad range of other quantum control scenarios.