Observing Parity Time Symmetry Breaking in a Josephson Parametric Amplifier

  1. Chandrashekhar Gaikwad,
  2. Daria Kowsari,
  3. Weijian Chen,
  4. and Kater W. Murch
A coupled two-mode system with balanced gain and loss is a paradigmatic example of an open quantum system that can exhibit real spectra despite being described by a non-Hermitian Hamiltonian. We utilize a degenerate parametric amplifier operating in three-wave mixing mode to realize such a system of balanced gain and loss between the two quadrature modes of the amplifier. By examining the time-domain response of the amplifier, we observe a characteristic transition from real-to-imaginary energy eigenvalues associated with the Parity-Time-symmetry-breaking transition.
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