Coherent control and distinguishability of quantum channels via PBS-diagrams

@article{Branciard2021CoherentCA,
  title={Coherent control and distinguishability of quantum channels via PBS-diagrams},
  author={Cyril Branciard and Alexandre Cl'ement and Mehdi Mhalla and Simon Perdrix},
  journal={ArXiv},
  year={2021},
  volume={abs/2103.02073}
}
Even though coherent control of quantum operations appears to be achievable in practice, it is still not yet well understood. Among theoretical challenges, standard completely positive trace preserving (CPTP) maps are known not to be appropriate to represent coherently controlled quantum channels. We introduce here a graphical language for coherent control of general quantum channels inspired by practical quantum optical setups involving polarising beam splitters (PBS). We consider different… 

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