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arXiv · 1808.04375

Sensitivity of quantum information to environment perturbations measured with a non-local out-of-time-order correlation function

Mohamad Niknam·Lea F. Santos·David G. Cory
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Abstract

In a quantum system coupled with a non-Markovian environment, quantum information may flow out of or in to the system. Measuring quantum information flow and its sensitivity to perturbations is important for a better understanding of open quantum systems and for the implementation of quantum technologies. Information gets shared between a quantum system and its environment by means of system-environment correlations (SECs) that grow during their interaction. We design a nuclear magnetic resonance (NMR) experiment to directly observe the evolution of the SECs and use the second moment of their distribution as a natural metric for quantifying the flow of information. In a second experiment, by accounting for the environment dynamics, we study the sensitivity of the shared quantum information to perturbations in the environment. The metric used in this case is a non-local out-of-time-order correlation function (OTOC). By analyzing the decay of the OTOC as a function of the SEC spread, instead of the evolution time, we are able to demonstrate its exponential behavior.

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Mohamad Niknam, Lea F. Santos, David G. Cory. 2018-08-13. Sensitivity of quantum information to environment perturbations measured with a non-local out-of-time-order correlation function. https://doi.org/10.1103/physrevresearch.2.013200

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