Observation of a 2D Bose Gas: From Thermal to Quasicondensate to Superfluid

Journal Article · Fri May 01 04:00:00 EDT 2009 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.102.170401· OSTI ID:21316653

Clade, P; Ryu, C; Ramanathan, A; Helmerson, K; Phillips, W D ^[1]

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1. Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8424 (United States) and Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742 (United States)

We present experimental results on a Bose gas in a quasi-2D geometry near the Berezinskii, Kosterlitz, and Thouless (BKT) transition temperature. By measuring the density profile after time of flight and the coherence length, we identify different states of the gas. We observe that the gas develops a bimodal distribution without long range order. In this regime, the gas presents a longer coherence length than the thermal cloud; it is quasicondensed but is not superfluid. Experimental evidence indicates that we also observe the superfluid transition (BKT transition). For a sufficiently long time of flight, we observe a trimodal distribution when the gas has developed a superfluid component.

• OSTI ID: 21316653
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 17 Vol. 102; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOSE-EINSTEIN GAS
COHERENCE LENGTH
SUPERFLUIDITY
TIME-OF-FLIGHT METHOD
TRANSITION TEMPERATURE