Decoherence and classicalization of continuous-time quantum walks on graphs

• URL: http://arxiv.org/abs/2204.01836v1
• Date: Mon, 4 Apr 2022 20:40:47 GMT
• Title: Decoherence and classicalization of continuous-time quantum walks on graphs
• Authors: Gabriele Bressanini, Claudia Benedetti and Matteo G. A. Paris
• Abstract summary: We show that the dynamics arising from decoherence, i.e. dephasing in the energy basis, do not fully classicalize the walker. On the other hand, dephasing in the position basis, as described by the Haken-Strobl master equation or by the quantum walk (QSW) model, induceally destroys the quantumness of the walker. We also investigate the speed of the classicalization process, and observe a faster convergence of the QC-distance to its value for intrinsic decoherence and the QSW models.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We address decoherence and classicalization of continuous-time quantum walks (CTQWs) on graphs. In particular, we investigate three different models of decoherence, and employ the quantum-classical (QC) dynamical distance as a figure of merit to assess whether, and to which extent, decoherence classicalizes the CTQW, i.e. turns it into the analogue classical process. We show that the dynamics arising from intrinsic decoherence, i.e. dephasing in the energy basis, do not fully classicalize the walker and partially preserves quantum features. On the other hand, dephasing in the position basis, as described by the Haken-Strobl master equation or by the quantum stochastic walk (QSW) model, asymptotically destroys the quantumness of the walker, making it equivalent to a classical random walk. We also investigate the speed of the classicalization process, and observe a faster convergence of the QC-distance to its asymptotic value for intrinsic decoherence and the QSW models, whereas in the Haken-Strobl scenario, larger values of the decoherence rate induce localization of the walker.

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