Emergence of quantum effects in a gas

Lev Vidmar, J. P. Ronzheimer, Michael Schreiber +6 more

Nir Navon, Alexander L. Gaunt, Robert P. Smith +1 more

Junichi Okamoto, Wen-Min Huang, Kyle Irwin +2 more

This work studies a one-dimensional Fermi gas embedded in a two-dimensional noninteracting Fermi gas. The authors demonstrate that various quantum phases emerge due to the mediated interaction among the one-dimensional gas, which can be controlled by varying the density of the two-dimensional Fermi gas.

V. E. Colussi, S. Musolino, S. J. J. M. F. Kokkelmans

We study the structure of a Bose-condensed gas after quenching interactions to unitarity. Using the method of cumulants, we decompose the evolving gas in terms of clusters. Within the quantum depletion we observe the emergence of two-body clusters bound purely by many-body effects, scaling continuously with the atomic density. As the unitary Bose gas forms, three-body Efimov clusters are first localized and then sequentially absorbed into the embedded atom-molecule scattering continuum of the surrounding depletion. These results highlight the interplay of quantum depletion and evolving scaling laws in the formation of the unitary Bose gas.

Tobias Damm, David Dung, Frank Vewinger +2 more

Phase transitions between different states of matter can profoundly modify the order in physical systems, with the emergence of ferromagnetic or topological order constituting important examples. Correlations allow the quantification of the degree of order and the classification of different phases. Here we report measurements of first-order spatial correlations in a harmonically trapped two-dimensional photon gas below, at and above the critical particle number for Bose-Einstein condensation, using interferometric measurements of the emission of a dye-filled optical microcavity. For the uncondensed gas, the transverse coherence decays on a length scale determined by the thermal de Broglie wavelength of the photons, which shows the expected scaling with temperature. At the onset of Bose-Einstein condensation, true long-range order emerges, and we observe quantum statistical effects as the thermal wave packets overlap. The excellent agreement with equilibrium Bose gas theory prompts microcavity photons as promising candidates for studies of critical scaling and universality in optical quantum gases.Phase transitions in quantum matter are related to correlation effects and they can change the ordering of material. Here the authors measure the first-order spatial correlation and the de Broglie wavelength for both thermal and condensed form of a photonic Bose gas in a dye-filled optical microcavity.

A. S. Bruev