First-order spatial coherence of ultracold Bose gas above phase transition temperature

Abstract

Abstract: One dimensional standing wave is used to generate a phase grating to study the first-order spatial coherence of ultracold Bose gas above the critical temperature in static-magnetic trap. Firstly, the interference patterns of the thermal gas are calculated theoretically, then the interference patterns of ultracold atomic gas above the critical temperature is also obtained experimentally. By comparing the visibility of interference patterns in theory and experiment, the properties of first-order spatial coherence are figured out. When the temperature of ultracold atomic gas is very close to the critical temperature in static-magnetic trap, the first-order spatial coherence is better than thermal gas. Increasing the temperature above a sufficiently high temperature, the coherence of the ultracold atomic gas is the same as thermal gas’ coherence, which is determined by deBroglie wavelength.

CLC Number:

Ο562.2

References

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