Journal of High Energy Physics (Sep 2022)
Target space entanglement in quantum mechanics of fermions at finite temperature
Abstract
Abstract We consider the target space entanglement in quantum mechanics of non-interacting fermions at finite temperature. Unlike pure states investigated in [1], the (Rényi) entanglement entropy for thermal states does not follow a simple bound because all states in the infinite-dimensional Hilbert space are involved. We investigate a general formula of the target space Rényi entropy for N fermions at finite temperature, and present numerical results of the entropy in a one-dimensional model. We also argue the large N behaviors with a comparison to the grand canonical ensemble.
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