Entanglement in non-unitary critical spin chains (Romain Couvreur)

Entanglement in non-unitary critical spin chains

  • Date: Dec 5, 2018
  • Time: 10:30 AM (Local Time Germany)
  • Speaker: Romain Couvreur
  • ENS Paris
  • Location: Max-Planck-Institut für Quantenoptik
  • Room: B 2.46
  • Host: MPQ, Theory Division
Entanglement entropy has proven invaluable to our understanding of quantum criticality. It is natural to try to extend the concept to “nonunitary quantum mechanics”, which has seen growing interest from areas as diverse as open quantum systems, noninteracting electronic disordered systems, or nonunitary conformal field theory (CFT).

I will discuss such an extension by focusing on physical systems that can be described as geometrical loop models. In the thermodynamic limit of unitary systems, the scaling of the entanglement entropy is known to be related to a universal quantity called central charge. I will show how this famous result is modified for the groundstates of non-hermitian Hamiltonians and introduce the concept of effective central charge as a measurement of the density of states.

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