相变温度以上超冷玻色气体的一阶空间相干性

J4 ›› 2016, Vol. 33 ›› Issue (4): 456-461.

相变温度以上超冷玻色气体的一阶空间相干性

孙超,王兵,朱强,熊德智

1中国科学院武汉物理与数学研究所，波谱与原子分子物理国家重点实验室，湖北武汉 430071； 2 中国科学院原子频标重点实验室，湖北武汉 430071； 3 中国科学院大学，北京 100049

收稿日期:2015-04-22 修回日期:2015-08-04 出版日期:2016-07-28 发布日期:2016-07-28
通讯作者: 熊德智（1980-），山西人，博士，从事超冷原子物理与应用的研究。 E-mail:wssxdz@wipm.ac.cn

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

Received:2015-04-22 Revised:2015-08-04 Published:2016-07-28 Online:2016-07-28

摘要/Abstract

摘要： 利用一维光学驻波场产生的相位光栅对静磁阱中相变温度以上超冷原子气体的一阶相干性质进行研究。在理论上首先计算了热原子的干涉图样,然后在实验上获得了相变温度以上超冷原子气体的干涉图样；通过对理论上和实验上原子气体的干涉图样的对比度进行比较发现：当温度非常接近相变温度的时候，原子气体的相干性明显好于热原子的相干性；随着温度的升高，原子气体的相干性逐渐减弱，最终与热原子的相干性完全相同。

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.

中图分类号:

Ο562.2

孙超王兵朱强熊德智. 相变温度以上超冷玻色气体的一阶空间相干性[J]. J4, 2016, 33(4): 456-461.

参考文献

[1]Anderson M H, Ensher J R, Matthews M R, et al.Observation of Bose-Einstein condensation in a dilute atomic vapor[J].Science, 1995, 269(5221):198-201 [2]Davis K B, Mewes M O, Andrews M R, et al.Bose-Einstein condensation in a gas of sodium atoms[J].Phys. Rev. Lett., 1995, 75(22):3969-3973 [3]Bradley C C, Sackett C A, Tollett J J, et al.Evidence of Bose-Einstein condensation in an atomic gas with attractive interactions[J].Phys. Rev. Lett., 1995, 75(9):1687-1690 [4]Andrews M R, Townsend C G, Miesner H J, et al.Observation of interference between two Bose condensates[J].Science, 1997, 275(5300):637-641 [5]Hagley E W, Deng L, Kozuma M, et al.Measurement of the coherence of a Bose-Einstein condensate[J].Phys. Rev. Lett., 1999, 83(16):3112-3115 [6]Stenger J, Inouye S, Chikkatur A P, et al.Bragg spectroscopy of a Bose-Einstein condensate[J].Phys. Rev. Lett., 1999, 82(23):4569-4573 [7]Barnert S M, Franke-Arnold S, Arnold A S, et al.Coherence length for a trapped Bose gas[J].J. Phys. B: At. Mol. Opt. Phys., 2000, 33(19):4177-4191 [8]Donner T, Ritter S, Bourdel T, et al.Critical behavior of a trapped interacting Bose gas[J].Science, 2007, 315(5818):1556-1558 [9]Xiong Wei, Zhou Xiaoji, Yue Xuguang, et al.Critical correlations in an ultra-cold Bose gas revealed by means of a temporal Talbot–Lau interferometer[J].Laser Phys. Lett., 2013, 10(12):125502- [10]Bezett A, Toth E, Blakie P B.Two-point correlations of a trapped interacting Bose gas at finite temperature[J].Phys. Rev. A, 2008, 77(2):023602- [11]Naraschewski M, Glauber R J.Spatial coherence and density correlations of trapped Bose gases[J].Phys. Rev. A, 1999, 59(6):4595-4607 [12]Bloch I, Hansch T W, Esslinger T.Measurement of the spatial coherence of a trapped Bose gas at the phase transition[J].Nature, 2000, 403(6766):166-170 [13]Anderson B P, Kasevich M A.Macroscopic quantum interference from atomic tunnel arrays[J].Science, 1998, 282(5394):1686-1689 [14]Orzel C, Tuchman A K, Fenselau M L, et al.Squeezed states in a Bose-Einstein condensate[J].Science, 2001, 291(5512):2386-2389 [15]Wang Bing, Zhu Qiang, Zhou Hailong, et al.Measurement of phase fluctuations of Bose-Einstein condensates in an optical lattice[J].Phys. Rev. A, 2012, 86(5):053609- [16]Zhou Hailong, Zhu Qiang, Wang Bing, et al.Measurement of phase fluctuations of Bose-Einstein condensates in one dimensional optical lattice[J].量子电子学报, 2014, 31(1):56-60 [17]Zambelli F, Pitaevskii L, Stamper-Kurn D M, et al.Dynamic structure factor and momentum distribution of a trapped Bose gas[J].Phys. Rev. A, 2000, 61(6):063608- [18]Sapiro R E, Zhang R, Raithel G.Reversible loss of superfluidity of a Bose–Einstein condensate in a 1D optical lattice[J].New J. Phys., 2009, 11(1):013013- [19]Kazantsev A P, Surdutovich G I, Yakovlev V P.On the quantum theory of resonance scattering of atoms by light[J].Jetp Lett., 1980, 31(9):509-512 [20]Gould P L, Ruff G A, Pritchard D E.Diffraction of atoms by light: The near-resonant Kapitza-Dirac effect[J].Phys. Rev. Lett., 1986, 56(8):827-830 [21]Bezett A, Blakie P B.Critical properties of a trapped interacting Bose gas[J].Phys. Rev. A, 2009, 79(3):033611- [22]Pethick C J, Smith H.Bose–Einstein Condensation in Dilute Gases. [J].Cambridge: Cambridge University Press, 2008, :21-23 [23]Lu Baolong, Tan Xinzhou, Wang Bing, et al.Phase transition to Bose-Einstein condensation for a bosonic gas confined in a combined trap[J].Phys. Rev. A, 2010, 82(5):053629-