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Testing quantum expanders is co-QMA-complete



Yi-Kai Liu, Stephen P. Jordan, Pawel Wocjan, Adam Bookatz


A quantum expander is a unital quantum channel that is rapidly mixing, has only a few Kraus operators, and can be implemented efficiently on a quantum computer. We consider the problem of estimating the mixing time (i.e., the spectral gap) of a quantum expander. We show that this problem is co-QMA-complete. This has applications to testing randomized constructions of quantum expanders, and studying thermalization of open quantum systems.
Theory of Computing Systems


Computational complexity, quantum information, quantum expanders, mixing time, thermalization


Liu, Y. , Jordan, S. , Wocjan, P. and Bookatz, A. (2013), Testing quantum expanders is co-QMA-complete, Theory of Computing Systems, [online], (Accessed May 25, 2024)


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Created May 31, 2013, Updated February 19, 2017