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Sub-Poissonian Fluctuations in a 1D Bose Gas: From the Quantum Quasicondensate to the Strongly Interacting Regime

T. Jacqmin, Julien Armijo, Tarik Berrada +2 more

We report on local, in situ measurements of atom number fluctuations in slices of a one-dimensional Bose gas on an atom chip setup. By using current modulation techniques to prevent cloud fragmentation, we are able to probe the crossover from weak to strong interactions. For weak interactions, fluctuations go continuously from super- to sub-Poissonian as the density is increased, which is a signature of the transition between the subregimes where the two-body correlation function is dominated, respectively, by thermal and quantum contributions. At stronger interactions, the super-Poissonian region disappears, and the fluctuations go directly from Poissonian to sub-Poissonian, as expected for a "fermionized" gas.We report on local, in situ measurements of atom number fluctuations in slices of a one-dimensional Bose gas on an atom chip setup. By using current modulation techniques to prevent cloud fragmentation, we are able to probe the crossover from weak to strong interactions. For weak interactions, fluctuations go continuously from super- to sub-Poissonian as the density is increased, which is a signature of the transition between the subregimes where the two-body correlation function is dominated, respectively, by thermal and quantum contributions. At stronger interactions, the super-Poissonian region disappears, and the fluctuations go directly from Poissonian to sub-Poissonian, as expected for a "fermionized" gas.

arXiv:1103.3028Physical Review LettersJun 10, 2011197 citations

Density fluctuations in a very elongated Bose gas : crossover from weakly to strongly interacing regimes and 1D-3D dimensional crossover

Isabelle Bouchoule, Julien Armijo, T. Jacqmin +1 more

In this seminar, we present results obtained on our atom-chip setup. Measuring in situ density fluctuations in very elongated gases we probe the physics of 1D Bose gases with repulsive interactions. We investigate the crossover from weakly to strongly interacting gases. For weakly interacting gases, we probed the transition from 1D physics to 3D physics.

Dec 13, 20100 citations

"Sub-poissonian atom-number fluctuations in 1D Bose gases : from the quantum weakly interacting regime to the fermionisation regime"

Isabelle Bouchoule

Apr 13, 20110 citations

Density fluctuations in a very elongated Bose gas : crossover from weakly to strongly interacing regimes and 1D-3D dimensionnal crossover

Isabelle Bouchoule

Dec 13, 20100 citations

Crossover to a quasi-condensate in a weakly interacting trapped 1D Bose gas

Karen V. Kheruntsyan, Isabelle Bouchoule, Gora V. Shlyapnikov

Bulletin of the American Physical SocietyMar 9, 20070 citations

Density fluctuations in a very elongated Bose gas : transition towards quasi-bec and 1D-3D crossover

Isabelle Bouchoule, Julien Armijo, T. Jacqmin +1 more

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. We also perform measurements of the third moment of atom number fluctuations. We find a positive skewness of the atom number distribution in the ideal gas regime and a reduced skewness compatible with zero in the quasi-condensate regime. For our parameters, the third moment is a thermodynamic quantity whose measurement constitutes a sensitive test of the equation of state and our results are in agreement with a modified Yang-Yang thermodynamic prediction. Moreover, we show that the measured skewness reveals the presence of true three body correlations in the system.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. We also perform measurements of the third moment of atom number fluctuations. We find a positive skewness of the atom number distribution in the ideal gas regime and a reduced skewness compatible with zero in the quasi-condensate regime. For our parameters, the third moment is a thermodynamic quantity whose measurement constitutes a sensitive test of the equation of state and our results are in agreement with a modified Yang-Yang thermodynamic prediction. Moreover, we show that the measured skewness reveals the presence of true three body correlations in the system.

Aug 23, 20100 citations

Sub-Poissonian fluctuations in a 1D Bose gas: from quantum quasi-condensate to the strongly interacting regime

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Sub-Poissonian fluctuations in a 1D Bose gas: from quantum quasi-condensate to the strongly interacting regime

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