Mapping out the quasi-condensate transition through the 1D-3D dimensional crossover

Julien Armijo (1) , Thibaut Jacqmin (1) , Karen Kheruntsyan (2) , Isabelle Bouchoule (1)

1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
2 ARC Centre of Excellence for Quantum-atom Optics

By measuring the density fluctuations in a highly elongated weakly interacting Bose gas, we observe and quantify the transition from the ideal gas to a quasi-condensate regime throughout the dimensional crossover from a purely 1D to an almost 3D gas. We show that that the entire transition region and the dimensional crossover are described surprisingly well by the modified Yang-Yang model. Furthermore, we find that at low temperatures the linear density at the quasi-condensate transition scales according to an interaction-driven scenario of a longitudinally uniform 1D Bose gas, whereas at high temperatures it scales according to the degeneracy-driven critical scenario of transverse condensation of a 3D ideal gas.

Domaines: Gaz Quantiques [cond-mat.quant-gas]; Optique [physics.optics]

Julien Armijo, Thibaut Jacqmin, Karen Kheruntsyan, Isabelle Bouchoule. Mapping out the quasi-condensate transition through the 1D-3D dimensional crossover. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2011, vol. 83, p. 021605. ⟨hal-00535794v2⟩