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  • Open Access

Quantum Metric Unveils Defect Freezing in Non-Hermitian Systems

Karin Sim1,*, Nicolò Defenu1, Paolo Molignini2,3, and R. Chitra1

  • 1Institute for Theoretical Physics, ETH Zürich, 8093 Zurich, Switzerland
  • 2Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
  • 3Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden

  • *Corresponding author: simkarin@phys.ethz.ch
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Phys. Rev. Lett. 131, 156501 – Published 13 October, 2023

DOI: https://doi.org/10.1103/PhysRevLett.131.156501

Abstract

Non-Hermiticity in quantum Hamiltonians leads to nonunitary time evolution and possibly complex energy eigenvalues, which can lead to a rich phenomenology with no Hermitian counterpart. In this work, we study the dynamics of an exactly solvable non-Hermitian system, hosting both PT-symmetric and PT-broken modes subject to a linear quench. Employing a fully consistent framework, in which the Hilbert space is endowed with a nontrivial dynamical metric, we analyze the dynamics of the generated defects. In contrast to Hermitian systems, our study reveals that PT-broken time evolution leads to defect freezing and hence the violation of adiabaticity. This physics necessitates the so-called metric framework, as it is missed by the oft used approach of normalizing quantities by the time-dependent norm of the state. Our results are relevant for a wide class of experimental systems.

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Phys. Rev. Lett. 131, 156501– Published 13 October, 2023
  • Received 4 January 2023
  • Revised 25 May 2023
  • Accepted 22 August 2023
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