Mixed-state entanglement from local randomized measurements


Andreas Elben, Richard Kueng, Hsin-Yuan Huang, Rick Van Bijnen, Christian Kokail, Marcello Dalmonte, Pasquale Calabrese, Barbara Kraus, John Preskill, Peter Zoller, and Benoît Vermersch. 2020. “Mixed-state entanglement from local randomized measurements.” arXiv:2007.06305.


We propose a method for detecting bipartite entanglement in a many-body mixed state based on estimating moments of the partially transposed density matrix. The estimates are obtained by performing local random measurements on the state, followed by post-processing using the classical shadows framework. Our method can be applied to any quantum system with single-qubit control. We provide a detailed analysis of the required number of experimental runs, and demonstrate the protocol using existing experimental data [Brydges et al, Science 364, 260 (2019)].