Cohering and decohering power of quantum channels

Mani, A ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1103/PhysRevA.92.032331
  3. Publisher: American Physical Society , 2015
  4. Abstract:
  5. We introduce the concepts of cohering and decohering power of quantum channels. Using the axiomatic definition of the coherence measure, we show that the optimization required for calculations of these measures can be restricted to pure input states and hence greatly simplified. We then use two examples of this measure, one based on the skew information and the other based on the l1 norm; we find the cohering and decohering measures of a number of one-, two-, and n-qubit channels. Contrary to the view at first glance, it is seen that quantum channels can have cohering power. It is also shown that a specific property of a qubit unitary map is that it has equal cohering and decohering power in any basis. Finally, we derive simple relations between cohering and decohering powers of unitary qubit gates and their tensor products, results which have physically interesting implications
  6. Keywords:
  7. Quantum computers ; Quantum entanglement ; Tensors ; Axiomatic definitions ; Input state ; Quantum channel ; Qubit channels ; Qubit gates ; Skew information ; Specific properties ; Tensor products ; Communication channels (information theory)
  8. Source: Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 92, Issue 3 , 2015 ; 10502947 (ISSN)
  9. URL: http://journals.aps.org/pra/abstract/10.1103/PhysRevA.92.032331