Channel Coding of a Quantum Measurement

TL;DR

This paper introduces a practical protocol for preserving quantum measurements over noisy channels using local operations and classical communication, demonstrated on IBM quantum computers.

Contribution

It proposes a novel, feasible method for channel coding of quantum measurements that does not require larger Hilbert spaces, applicable to qubit states and ensembles.

Findings

Protocol preserves measurements over arbitrary channels

Demonstrated on IBM quantum computers

Applicable to pairs of qubit states and ensembles

Abstract

In this work, we consider the preservation of a measurement for quantum systems interacting with an environment. Namely, a method of preserving an optimal measurement over a channel is devised, what we call channel coding of a quantum measurement in that operations are applied before and after a channel in order to protect a measurement. A protocol that preserves a quantum measurement over an arbitrary channel is shown only with local operations and classical communication without the use of a larger Hilbert space. Therefore, the protocol is readily feasible with present day's technologies. Channel coding of qubit measurements is presented, and it is shown that a measurement can be preserved for an arbitrary channel for both i) pairs of qubit states and ii) ensembles of equally probable states. The protocol of preserving a quantum measurement is demonstrated with IBM quantum computers.