TY - JOUR

T1 - Quantum Network Discrimination

AU - Hirche, Christoph

N1 - Funding Information: I would like to thank Mario Berta, Mark M. Wilde and Andreas Winter for helpful comments and references. Furthermore, I acknowledge financial support from VILLUM FONDEN via the QMATH Centre of Excellence (Grant No.10059) and the QuantERA ERA-NET Cofund in Quantum Technologies implemented within the European Union’s Horizon 2020 Programme (Quan-tAlgo project) via the Innovation Fund Denmark.

PY - 2023

Y1 - 2023

N2 - Discrimination between objects, in particular quantum states, is one of the most fundamental tasks in (quantum) information theory. Recent years have seen significant progress towards extending the framework to point-to-point quantum channels. However, with technological progress the focus of the field is shifting to more complex structures: Quantum networks. In contrast to channels, networks allow for intermediate access points where information can be received, processed and reintroduced into the network. In this work we study the discrimination of quantum networks and its fundamental limitations. In particular when multiple uses of the network are at hand, the roster of available strategies becomes increasingly complex. The simplest quantum network that captures the structure of the problem is given by a quantum superchannel. We discuss the available classes of strategies when considering n copies of a superchannel and give fundamental bounds on the asymptotically achievable rates in an asymmetric discrimination setting. Furthermore, we discuss achievability, symmetric network discrimination, the strong converse exponent, generalization to arbitrary quantum networks and finally an application to an active version of the quantum illumination problem.

AB - Discrimination between objects, in particular quantum states, is one of the most fundamental tasks in (quantum) information theory. Recent years have seen significant progress towards extending the framework to point-to-point quantum channels. However, with technological progress the focus of the field is shifting to more complex structures: Quantum networks. In contrast to channels, networks allow for intermediate access points where information can be received, processed and reintroduced into the network. In this work we study the discrimination of quantum networks and its fundamental limitations. In particular when multiple uses of the network are at hand, the roster of available strategies becomes increasingly complex. The simplest quantum network that captures the structure of the problem is given by a quantum superchannel. We discuss the available classes of strategies when considering n copies of a superchannel and give fundamental bounds on the asymptotically achievable rates in an asymmetric discrimination setting. Furthermore, we discuss achievability, symmetric network discrimination, the strong converse exponent, generalization to arbitrary quantum networks and finally an application to an active version of the quantum illumination problem.

UR - http://www.scopus.com/inward/record.url?scp=85169680308&partnerID=8YFLogxK

U2 - 10.22331/q-2023-07-25-1064

DO - 10.22331/q-2023-07-25-1064

M3 - Article

AN - SCOPUS:85169680308

VL - 7

JO - Quantum

JF - Quantum

SN - 2521-327X

ER -