A two-disk approach to the synthesis of coherent passive equalizers for linear quantum systems

TL;DR

This paper introduces an improved method for synthesizing coherent passive equalizers for quantum systems, leveraging a two-disk problem approach from classical control to enhance filter design for quantum communication channels.

Contribution

It develops a novel synthesis method for quantum equalizers based on a two-disk control problem, broadening applicability to various quantum communication channels.

Findings

The method applies to a broader class of quantum channels.

It improves the design of near-optimal quantum filters.

The approach connects quantum filter synthesis with classical control problems.

Abstract

The coherent equalization problem consists in designing a quantum system acting as a mean-square near-optimal filter for a given quantum communication channel. The paper develops an improved method for the synthesis of transfer functions for such equalizing filters, based on a linear quantum system model of the channel. The method draws on a connection with the two-disk problem of ${H}_{\infty}$ control for classical (i.e., non-quantum) linear uncertain systems. Compared with the previous methods, the proposed method applies to a broader class of linear quantum communication channels.