Roton-Maxon Excitation Spectrum of Bose Condensates in a Shaken Optical Lattice
Roton-Maxon Excitation Spectrum of Bose Condensates in a Shaken Optical Lattice
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DOI：
10.1103/physrevlett.114.055301
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发表时间：
2015-02-03
影响因子：
8.6
通讯作者：
Chin, Cheng
中科院分区：
文献类型：
--
作者：
Ha, Li-Chung;Clark, Logan W.;Chin, Cheng
我们目前的实验证据表明，相互作用的玻色凝聚体在一个震动的光学晶格开发的roton-maxon激发光谱，通常与超流氦的功能。该特性源于振动晶格中的双势阱色散，可由原子间相互作用和晶格调制幅度共同控制。我们确定的激发光谱，使用布拉格光谱和测量的临界速度通过拖动一个弱的散斑势通过凝聚-这两种技术是基于一个数字化的设备。我们的色散测量与修改后的Bogoliubov模型吻合得很好。
We present experimental evidence showing that an interacting Bose condensate in a shaken optical lattice develops a roton-maxon excitation spectrum, a feature normally associated with superfluid helium. The roton-maxon feature originates from the double-well dispersion in the shaken lattice, and can be controlled by both the atomic interaction and the lattice modulation amplitude. We determine the excitation spectrum using Bragg spectroscopy and measure the critical velocity by dragging a weak speckle potential through the condensate-both techniques are based on a digital micromirror device. Our dispersion measurements are in good agreement with a modified Bogoliubov model.