Quantum critical behavior influenced by measurement backaction in ultracold gases

Yuto Ashida, Shunsuke Furukawa, Masahito Ueda

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)


Recent realizations of quantum gas microscopy offer the possibility of continuous monitoring of the dynamics of a quantum many-body system at the single-particle level. By analyzing effective non-Hermitian Hamiltonians for interacting bosons in an optical lattice and continuum, we demonstrate that the backaction of quantum measurement shifts the quantum critical point and gives rise to a unique critical phase beyond the terrain of the standard universality class. We perform mean-field and strong-coupling-expansion analyses and show that non-Hermitian contributions shift the superfluid-Mott-insulator transition point. Using a low-energy effective field theory, we discuss critical behavior of the one-dimensional interacting Bose gas subject to the measurement backaction. We derive an exact ground state of the effective non-Hermitian Hamiltonian and find a unique critical behavior beyond the Tomonaga-Luttinger liquid universality class. We propose experimental implementations of postselections using a quantum gas microscope to simulate the non-Hermitian dynamics and argue that our results can be investigated with current experimental techniques in ultracold atoms.

Original languageEnglish
Article number053615
JournalPhysical Review A
Issue number5
Publication statusPublished - 2016
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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