拉曼耦合作用下玻色-爱因斯坦凝聚的磁化性质
Magnetic Properties of Bose-Einstein Condensate with Raman Coupling

摘要 研究双分量玻色气体在拉曼耦合作用下的磁化性质。对于宏观占据单一动量态的玻色?爱因斯坦凝聚, 磁化强度和磁化率分别与凝聚动量和有效质量存在普适的线性关系, 这些普适关系不依赖于拉曼耦合的强度、失谐大小及原子间的相互作用。推导出磁化率与有效质量的线性关系, 可以在经典物理图像下描述简谐势阱中凝聚体的偶极振荡, 自旋空间、动量空间及坐标空间的振幅之比可表达为有效质量和自旋磁化率的解析形式。这组振幅关系对于亚稳态附近的小幅振荡也同样适用。
Abstract The author studies the magnetic properties of two-component Bose with interspecies Raman coupling. For the condensate occupying single momentum state, the spin polarization and the spin susceptibility are linear to the condensation momentum and the effective mass respectively. Such universal relations are independent of the coupling strength, Raman detuning and interactions between atoms. With these relations, the dipole oscillation of a Raman coupled condensate in a harmonic trap is described by a classic picture, and the ratios of oscillation amplitudes in momentum space, spin space and coordinate space are obtained analytically in terms of the effective mass and the spin susceptibility. The results about the oscillation amplitudes are also valid for the dipole mode of a meta-stable condensate.