Bayesian and Markovian classical feedforward for discriminating qubit channels

TL;DR

This paper compares Bayesian and Markovian strategies in a simple adaptive protocol for discriminating between two qubit channels, highlighting the limited advantage of Bayesian methods.

Contribution

It introduces and analyzes a simple adaptive protocol using Helstrom measurements and classical feedforward for qubit channel discrimination, contrasting Bayesian and Markovian approaches.

Findings

Bayesian strategy offers slight advantage over Markovian in certain parameter regions.

The protocol employs separable inputs and classical information feedforward.

Performance differences are limited to specific parameter ranges.

Abstract

We address the issue of multishot discrimination between two qubit channels by invoking a simple adaptive protocol that employs Helstrom measurement at each step and classical information feedforward, beside separable inputs. We contrast the performance of Bayesian and Markovian strategies. We show that the former is only slightly advantageous and for a limited parameters' region.