Chaos in quantum channels

We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back up our results with numerics in two non-integrable…

• DA
  David and Lucile Packard Foundation
• UD
  U.S. Department of Energy
• JT
  John Templeton Foundation
• HF
  Hertz Foundation

  Award: DE-SC0012567
• GO
  Government of Canada
• IC
  Industry Canada
• KI
  Kavli Institute for Theoretical Physics, University of California, Santa Barbara