Complementarity of information sent via different bases

Shengjun Wu, Sixia Yu, Klaus Mølmer

Published 2008-11-14, updated 2009-02-10Version 2

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.