Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition
arXiv:1503.05565 · doi:10.1038/ncomms8046
Abstract
The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied due to the diluteness of the system. Here, we report on a direct, real-time and non-destructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system.
17 pages including supplementary information
References in corpus (9)
- Cold atoms in cavity-generated dynamical optical potentials
- Cavity QED with a Bose-Einstein condensate
- Spatial quantum noise interferometry in expanding ultracold atom clouds
- Roton-type mode softening in a quantum gas with cavity-mediated long-range interactions
- Keldysh approach for non-equilibrium phase transitions in quantum optics: beyond the Dicke model in optical cavities
- Bose-Einstein condensates in 1D optical lattices: compressibility, Bloch bands and elementary excitations
- Cavity enhanced light scattering in optical lattices to probe atomic quantum statistics
- Light scattering from ultracold atoms in optical lattices as an optical probe of quantum statistics
- Damping of quasiparticles in a Bose-Einstein condensate coupled to an optical cavity
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- Quantum features of entropy production in driven-dissipative transitions
- Gapped spectrum in pair-superfluid bosons
- The Single Particle Excitation Spectrum of Degenerate Fermi gases in a ring cavity