Quantum Flutter: Signatures and Robustness

Michael Knap 1, 2, 3 Charles J. M. Mathy 3, 4 Martin Ganahl 2 Mikhail B. Zvonarev 5 Eugene Demler 4

Physical Review Letters, American Physical Society, 2014, 112, pp.015302

We investigate the motion of an impurity particle injected with finite velocity into an interacting one-dimensional quantum gas. Using large-scale numerical simulations based on matrix product states, we observe and quantitatively analyze long-lived oscillations of the impurity momentum around a non-zero saturation value, called quantum flutter. We show that the quantum flutter frequency is equal to the energy difference between two branches of collective excitations of the model. We propose an explanation of the finite saturation momentum of the impurity based on the properties of the edge of the excitation spectrum. Our results indicate that quantum flutter exists away from integrability, and provide parameter regions in which it could be observed in experiments with ultracold atoms using currently available technology.

  • 1. Department of Physics
  • 2. Institute of Theoretical and Computational Physics
  • 3. CFA - Harvard-Smithsonian Center for Astrophysics
  • 4. Department of Physics
  • 5. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques