Complementarity of information sent via different bases

TL;DR

This paper quantifies how information transmitted through different mutually unbiased bases in quantum systems is complementary, providing bounds that support the security of quantum key distribution.

Contribution

It introduces upper bounds on accessible information when the basis is unknown, highlighting the complementarity of information in different MUBs for quantum communication.

Findings

Upper bounds on information accessible without basis knowledge

Demonstrates complementarity of information in different MUBs

Supports security proofs in quantum key distribution

Abstract

We discuss quantitatively the complementarity of information transmitted by a quantum system prepared in a basis state in one out of several different mutually unbiased bases (MUBs). We obtain upper bounds on the information available to a receiver who has no knowledge of which MUB was chosen by the sender. These upper bounds imply a complementarity of information encoded via different MUBs and ultimately ensure the security in quantum key distribution protocols.