Efficient Quantum Filtering for Quantum Feedback Control

TL;DR

This paper introduces an efficient numerical method for quantum filtering that enhances real-time quantum feedback control, especially in systems with inefficient measurements, demonstrated through a two-qubit entanglement example.

Contribution

It presents a novel, computationally efficient numerical scheme for recursive quantum filtering applicable to feedback control in quantum systems.

Findings

Robust quantum trajectories suitable for feedback

Reduced computational complexity for quantum filtering

Feasibility of real-time quantum control in two-qubit systems

Abstract

We discuss an efficient numerical scheme for the recursive filtering of diffusive quantum stochastic master equations. We show that the resultant quantum trajectory is robust and may be used for feedback based on inefficient measurements. The proposed numerical scheme is amenable to approximation, which can be used to further reduce the computational burden associated with calculating quantum trajectories and may allow real-time quantum filtering. We provide a two-qubit example where feedback control of entanglement may be within the scope of current experimental systems.