A note on coherence power of Ndimensional unitary operators
Abstract
The coherence power of a quantum channel, that is, its ability to increase the coherence of input states, is a fundamental concept within the framework of the resource theory of coherence. In this note we discuss various possible definitions of coherence power. Then we prove that the coherence power of a unitary operator acting on a qubit, computed with respect to the $l_1$coherence measure, can be calculated by maximizing its coherence gain over pure incoherent states. We proceed to show that this result fails for dimensions N>2, that is, the maximal coherence gain is found when acting on a state with nonvanishing coherence.
 Publication:

arXiv eprints
 Pub Date:
 October 2015
 DOI:
 10.48550/arXiv.1510.06683
 arXiv:
 arXiv:1510.06683
 Bibcode:
 2015arXiv151006683G
 Keywords:

 Quantum Physics
 EPrint:
 5 pages, no figures