Realizing Fulde-Ferrell Superfluids via a Dark-State Control of Feshbach Resonances
Realizing Fulde-Ferrell Superfluids via a Dark-State Control of Feshbach Resonances
复制标题
通过费什巴赫共振的暗态控制实现富尔德-费雷尔超流体
DOI：
10.1103/physrevlett.120.045302
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发表时间：
2018
影响因子：
8.6
通讯作者：
Xia-Ji Liu
中科院分区：
文献类型：
--
作者：
Lianyi He;Hui Hu;Xia-Ji Liu
我们提出了在超冷双组分费米气体中通过利用多普勒频移斯塔克效应产生闭通道暗态来光学调谐原子的磁Feshbach共振，从而实现长期以来所寻求的具有非零动量对的Fulde-Ferrell超流性。在这个方案中，两个反向传播的光场被施加到耦合两个分子状态在封闭的通道中的激发分子状态，导致显着违反伽利略不变性的暗态制度，因此富尔德-费雷尔超流的可能性。我们开发了一个两体和多体问题的场论公式，并预测富尔德-费雷尔状态具有显着的属性，如各向异性的单粒子色散关系，抑制超流密度在零温度下，各向异性的声速，和rotonic集体模式。后两个特征可以用布拉格光谱学进行实验探测，为富尔德-费雷尔超流性提供了确凿的证据。
We propose that the long-sought Fulde-Ferrell superfluidity with nonzero momentum pairing can be realized in ultracold two-component Fermi gases oforatoms by optically tuning their magnetic Feshbach resonances via the creation of a closed-channel dark state with a Doppler-shifted Stark effect. In this scheme, two counterpropagating optical fields are applied to couple two molecular states in the closed channel to an excited molecular state, leading to a significant violation of Galilean invariance in the dark-state regime and hence to the possibility of Fulde-Ferrell superfluidity. We develop a field theoretical formulation for both two-body and many-body problems and predict that the Fulde-Ferrell state has remarkable properties, such as anisotropic single-particle dispersion relation, suppressed superfluid density at zero temperature, anisotropic sound velocity, and rotonic collective mode. The latter two features can be experimentally probed using Bragg spectroscopy, providing a smoking-gun proof of Fulde-Ferrell superfluidity.