Quantum many-body dynamics under continuous observation (Prof. M. Ueda)

  • Datum: 23.01.2018
  • Uhrzeit: 14:30 - 15:30
  • Vortragende(r): Prof. Dr. Masahito Ueda
  • Department of Physics, University of Tokyo, Japan
  • Raum: New Lecture Hall, Room B 0.32
  • Gastgeber: MPQ
Quantum gas microscopy has revolutionalized our approach to quantum many-body systems where atoms trapped in an optical lattice can be observed in real time at the single-particle level.

At such extreme precision, the measurement backaction due to Heisenberg’s uncertainty relation can no longer be ignored. One should naturally be led to the question of whether or not many-body dynamics will be modified and, if so, in what way. We will address this issue by focusing on few-body dynamics and quantum critical phenomena. In the former, the measurement distinguishablity of multiple particles leads to a complete suppression of relative positional decoherence and quantum correlations persist under continuous observation in a manner analogous to decoherence-free subspace (PRA95, 022124 (2017)). In the latter, the measurement backaction is shown to shift the quantum critical point and yield a unique critical phase beyond the scope of the standard universality class (PRA94, 053615 (2017); Nat. Commun. 8, 15791 (2017)). We also find that the propagation of correlations can exceed the Lieb-Robinson bound under such continuous observation (arXiv:1709.03704). Continuous observation also restricts the Hilbert space and the emergent nontrivial Berry phase yields some startling effects such as the Zeno Hall effect and retroreflection (PRL118, 200401 (2017)).

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