Transition of d -level quantum systems through quantum channels with correlated noise

Fahmi, A ; Sharif University of Technology | 2007

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  1. Type of Document: Article
  2. DOI: 10.1103/PhysRevA.75.042301
  3. Publisher: 2007
  4. Abstract:
  5. Entanglement and entanglement assisted are useful resources to enhance the mutual information of the Pauli channels, when the noise on consecutive uses of the channel has some partial correlations. In this paper, we study quantum-communication channels in d -dimensional systems and derive the mutual information of the quantum channels for maximally entangled states and product states coding with correlated noise. Then, we compare fidelity between these states. Our results show that there exists a certain fidelity memory threshold, which depends on the dimension of the Hilbert space (d) and the properties of noisy channels. We calculate the classical capacity of a particular correlated noisy channel and show that in order to achieve Holevo limit, we must use d particles with d degrees of freedom. Our results show that entanglement is a useful means to enhance the mutual information. We choose a special nonmaximally entangled state and show that in the quasiclassical depolarizing and quantum depolarizing channels, maximum classical capacity in the higher memory channels is given by the maximally entangled state. Hence, our results show that for high error channels in every degree of memory, maximally entangled states have better mutual information. © 2007 The American Physical Society
  6. Keywords:
  7. Communication channels (information theory) ; Electron energy levels ; Electronic structure ; Hilbert spaces ; Entangled states ; Holevo limit ; Memory channels ; Noisy channels ; Quantum theory
  8. Source: Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 75, Issue 4 , 2007 ; 10502947 (ISSN)
  9. URL: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.75.042301