Detection of properties and capacities of quantum channels

TL;DR

This paper reviews a unified method for detecting properties and lower bounds of quantum channel capacities without full process tomography, using entangled states and minimal local measurements.

Contribution

It introduces a simplified approach to assess quantum channels' properties and capacities efficiently, avoiding complex tomography procedures.

Findings

Effective detection of quantum channel properties

Lower bounds on quantum capacities established

Method reduces measurement complexity

Abstract

We review in a unified way a recently proposed method to detect properties of unknown quantum channels and lower bounds to quantum capacities, without resorting to full quantum process tomography. The method is based on the preparation of a fixed bipartite entangled state at the channel input or, equivalently, an ensemble of an overcomplete set of single-system states, along with few local measurements at the channel output.