November 2022

Research work by Dr. Siddhartha Das on Upper Bounds on Device-Independent Quantum Key Distribution Rates in Static and Dynamic Scenarios was published in Physical Review Applied on 10 November. 

The others authors of this paper are Eneet Kaur, Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, Canada and Karol Horodecki, Institute of Informatics, National Quantum Information Centre in Gdańsk, Faculty of Mathematics, Physics and Informatics and International Centre for Theory of Quantum Technologies, University of Gdańsk,   Poland.

Research work as explained by the authors:

In this work, we develop upper bounds on key rates for device-independent quantum key distribution (DI-QKD) protocols and devices. We study the reduced cc-squashed entanglement and show that it is a convex functional. As a result, we show that the convex hull of the currently known bounds is a tighter upper bound on the device-independent key rates of the standard Clauser-Horne-Shimony-Holt (CHSH)-based protocol. We further provide tighter bounds for DI-QKD key rates achievable by any protocol applied to the CHSH-based device. This bound is based on reduced relative entropy of entanglement optimized over decompositions into local and nonlocal parts. In the dynamical scenario of quantum channels, we obtain upper bounds for device-independent private capacity for the CHSH-based protocols. We show that the device-independent private capacity for the CHSH-based protocols on depolarizing and erasure channels is limited by the secret key capacity of dephasing channels.

Full paper: https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.18.054033

Physical Review Applied (PRApplied) publishes high-quality papers that bridge the gap between engineering and physics, and between current and future technologies. PRApplied welcomes papers from both the engineering and physics communities, in academia and industry. PRApplied publishes research with strong and clear ties to applications, and that offers fresh insight into physical phenomena. PRApplied publishes Review Articles, detailed Research Articles, and Letters, which are short papers of particular significance and/or topical interest. The journal has a flexible approach to article lengths and welcomes submission of longer papers that provide depth and authority in their subject areas.