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Power of Quantum Channels for Creating Quantum Correlations

Abad, Tahereh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45071 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Karimipour, Vahid; Memarzadeh Esfahani, Laleh
  7. Abstract:
  8. In recent studies, it has been shown that entanglement is not the only kind of genuinely quantum correlation. There exist models of quantum computation that provide exponential speed up over the best known classical algorithms and don’t have any quantum entanglement. These models show that in some cases separable state can be very useful in quantum computing models. Look for a property that causes the performance of these scenarios, quantum correlation being one of the most important concepts, including but not limited to entanglement. Local noise can produce quantum correlations on an initially classically correlated state, provided that it is not represented by a unital or semiclassical channel. In this thesis we first review quantifying total correlations in a bipartite quantum state and introduce mutual information as the measure of total correlations. The total correlations in a bipartite quantum state into a quantum and a purely classical part, so we quantify the purely quantum part of the total bipartite correlations
    and explain that entanglement is one kind of quantum correlations. Then we find the power of any given local channel for producing quantum correlations on an initially classically correlated state. We introduce a computable measure for quantifying the quantum correlations in quantum-classical states, which is based on the noncommutativity of ensemble states in one party of the composite system. Using this measure we show that the amount of quantum correlations produced is proportional to the classical correlations in the initial state. The power of an arbitrary channel for producing quantum correlations is found by averaging over all possible initial states. Finally, we compare our measure with the geometrical measure of quantumness for a subclass of quantum-classical sates, for which we have been able to find a closed analytical expression
  9. Keywords:
  10. Entanglement ; Solidarity ; Quantum Correlation ; Unilary Channel ; Local Channel ; Quantum Channel

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