English

Extension maps

Quantum Physics 2007-05-23 v1

Abstract

We define extension maps as maps that extend a system (through adding ancillary systems) without changing the state in the original system. We show, using extension maps, why a completely positive operation on an initially entangled system results in a non positive mapping of a subsystem. We also show that any trace preserving map, either positive or negative, can be decomposed in terms of an extension map and a completely positive map.

Keywords

Cite

@article{arxiv.quant-ph/0503119,
  title  = {Extension maps},
  author = {Aik-meng Kuah and E. C. G. Sudarshan},
  journal= {arXiv preprint arXiv:quant-ph/0503119},
  year   = {2007}
}

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6 pages