Southwest Quantum Information and Technology

Entanglement and secret key agreement capacities of bipartite quantum interactions and read-only memory devices

Presenting Author: Siddhartha Das, Louisiana State University
Contributing Author(s): Stefan Baeuml, Mark M. Wilde

A bipartite quantum interaction or bidirectional quantum channel corresponds to the most general quantum interaction that can occur between two quantum systems. In this work, we determine bounds on the capacities of bipartite interactions for entanglement generation and secret key agreement. Our upper bound on the entanglement generation capacity of a bipartite quantum interaction is given by a quantity that we introduce, called the bidirectional max-Rains information. Our upper bound on the secret key agreement capacity of a bipartite quantum interaction is given by a related quantity, called the bidirectional max-relative entropy of entanglement. Observing that quantum reading is a particular kind of bipartite quantum interaction, we leverage our bounds from the bidirectional setting to deliver bounds on the capacity of a task that we introduce, called private reading of a quantum memory cell. Given a set of quantum channels, the goal of private reading is for an encoder to form codewords from these channels, in order to establish secret key with a party who controls one input and one output of the channels, while a passive eavesdropper has access to the environment of the channels. We derive both lower and upper bounds on the capacities of private reading protocols. We then extend these results to determine achievable rates for the generation of entanglement between two distant parties who have coherent access to controlled point-to-point channels.

(Session 5 : Thursday from 5:00pm - 7:00 pm)