Distance measures for quantum states and channels: properties and applications.

Abstract

Discriminating between quantum states and channels is an important task in the field of quantum computation and quantum information theory. Metrics and statistical distances form the tools for various approaches proposed for this task. We analyse existing results to compare properties, main purpose, computability and advantages and disadvantages of each approach.This article is part of the theme issue 'Numerical analysis, spectral graph theory, orthogonal polynomials and quantum algorithms'.