English

The depolarising channel and Horns problem

Quantum Physics 2013-02-27 v1 Information Theory math.IT Representation Theory

Abstract

We investigate the action of the depolarising (qubit) channel on permutation invariant input states. More specifically, we raise the question on which invariant subspaces the output of the depolarising channel, given such special input, is supported. An answer is given for equidistributed states on isotypical subspaces, also called symmetric Werner states. Horns problem and two of the corresponding inequalities are invoked as a method of proof.

Keywords

Cite

@article{arxiv.1302.6262,
  title  = {The depolarising channel and Horns problem},
  author = {Janis Noetzel},
  journal= {arXiv preprint arXiv:1302.6262},
  year   = {2013}
}

Comments

7 pages, no figures

R2 v1 2026-06-21T23:32:27.479Z