Number-Phase Wigner Representation for Scalable Stochastic Simulations of Controlled Quantum Systems

TL;DR

This paper introduces a number-phase Wigner representation that enables more efficient and longer convergence stochastic simulations of controlled quantum systems, especially large bosonic systems like BECs and atom lasers.

Contribution

The authors develop a scalable stochastic simulation method based on the NPW phase-space representation, improving convergence and precision over traditional coherent state methods.

Findings

NPW-based stochastic method converges ten times longer than coherent state methods.

Enhanced simulation accuracy for large bosonic quantum systems.

Potential for realistic control and measurement simulations in quantum technologies.

Abstract

Simulation of conditional master equations is important to describe systems under continuous measurement and for the design of control strategies in quantum systems. For large bosonic systems, such as BEC and atom lasers, full quantum field simulations must rely on scalable stochastic methods whose convergence time is restricted by the use of representations based on coherent states. Here we show that typical measurements on atom-optical systems have a common form that allows for an efficient simulation using the number-phase Wigner (NPW) phase-space representation. We demonstrate that a stochastic method based on the NPW can converge over an order of magnitude longer and more precisely than its coherent equivalent. This opens the possibility of realistic simulations of controlled multi-mode quantum systems.