Information capacity of continuous variable measurement channel

TL;DR

This paper investigates the classical capacity of infinite-dimensional quantum measurement channels, providing explicit formulas for Gaussian channels and applying them to specific models like the one-mode squeezed-noise heterodyne measurement.

Contribution

It derives an explicit formula for the classical capacity of Gaussian measurement channels without assuming global gauge symmetry, under a threshold condition.

Findings

Explicit capacity formula for Gaussian measurement channels

Capacity computation for one-mode squeezed-noise heterodyne measurement

Conditions enabling application of general results to specific models

Abstract

The present paper is devoted to investigation of the classical capacity of infinite-dimensional quantum measurement channels. A number of usable conditions are introduced that enable us to apply previously obtained general results to specific models, in particular, to the multi-mode bosonic Gaussian measurement channels. An explicit formula for the classical capacity of the Gaussian measurement channel is obtained in this paper without assuming the global gauge symmetry, solely under certain "threshold condition". The result is illustrated by the capacity computation for one-mode squeezed-noise heterodyne measurement channel.