Hakan E. Türeci

Stochastic Differential Equations for Quantum Dynamics of Spin-Boson Networks

  1. Stephan Mandt,
  2. Darius Sadri,
  3. Andrew A. Houck,
  4. and Hakan E. Türeci
The quantum dynamics of open many-body systems poses a challenge for computational approaches. Here we develop a stochastic scheme based on the positive P phase-space representation
to study the nonequilibrium dynamics of coupled spin-boson networks that are driven and dissipative. Such problems are at the forefront of experimental research in cavity and solid state realizations of quantum optics, as well as cold atom physics, trapped ions and superconducting circuits. We demonstrate and test our method on a driven, dissipative two-site system, each site involving a spin coupled to a photonic mode, with photons hopping between the sites, where we find good agreement with Monte Carlo Wavefunction simulations. In addition to numerically reproducing features recently observed in an experiment [Phys. Rev. X 4, 031043 (2014)], we also predict a novel steady state quantum dynamical phase transition for an asymmetric configuration of drive and dissipation.
arxiv pdf

Observation of a Dissipation-Induced Classical to Quantum Transition

  1. James Raftery,
  2. Darius Sadri,
  3. Sebastian Schmidt,
  4. Hakan E. Türeci,
  5. and Andrew A. Houck
The emergence of non-trivial structure in many-body physics has been a central topic of research bearing on many branches of science. Important recent work has explored the non-equilibrium
quantum dynamics of closed many-body systems. Photonic systems offer a unique platform for the study of open quantum systems. We report here the experimental observation of a novel dissipation driven dynamical localization transition of strongly correlated photons in an extended superconducting circuit. Monitoring the homodyne signal reveals this transition to be from a regime of classical oscillations into a macroscopically self-trapped state manifesting revivals, a fundamentally quantum phenomenon. This experiment also demonstrates a new class of scalable quantum simulators with well controlled coherent and dissipative dynamics suited to the study of quantum many-body phenomena out of equilibrium.
arxiv pdf