Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences.

  title={Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences.},
  author={Martin G{\"a}rttner and Philipp Hauke and Ana Maria Rey},
  journal={Physical review letters},
  volume={120 4},
Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has… 
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  • D. Girolami
  • Physics, Medicine
    Physical review letters
  • 2014
An experimental scheme is presented implementable with current technology which evaluates the quantum coherence of an unknown state of a d-dimensional system by performing two programmable measurements on an ancillary qubit, in place of the O(d2) direct measurements required by full state reconstruction.