The Kibble-Zurek scaling at exceptional points

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The Kibble-Zurek scaling at exceptional points
2019. 10. 18. 10:15
Building F, stairway III., seminar room of the Dept. of Theoretical Physics
Balázs Dóra (BME)

Exceptional points (EPs) are ubiquitous in non-hermitian systems, and represent the complex counterpart of  critical points. By driving a system through a critical point at finite rate induces defects, described by the Kibble-Zurek mechanism, which finds applications in diverse fields of physics. Here we generalize this to a ramp across an EP. We find that  adiabatic time evolution brings the system into an eigenstate of the final non-hermitian Hamiltonian and demonstrate that for a variety of drives through an EP, the defect density obeys a universal scaling form in terms of the usual critical exponents and the speed of the drive. Defect production is suppressed compared to the conventional hermitian case as the defect state can decay back to the ground state close to the EP.