Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA.
Phys Rev Lett. 2012 Sep 7;109(10):103002. doi: 10.1103/PhysRevLett.109.103002.
We explore the anisotropic nature of Feshbach resonances in the collision between ultracold highly magnetic submerged-shell dysprosium atoms in their energetically lowest magnetic sublevel, which can only occur due to couplings to rotating bound states. This is in contrast to well-studied alkali-metal atom collisions, where broadest (strongest) Feshbach resonances are hyperfine induced and due to rotationless bound states. Our first-principle coupled-channel calculation of the collisions between these spin-polarized bosonic dysprosium atoms reveals a strong interplay between the anisotropies in the dispersion and magnetic dipole-dipole interaction. The former anisotropy is absent in alkali-metal and chromium collisions. We show that both types of anisotropy significantly affect the Feshbach spectrum as a function of an external magnetic field. Effects of the electrostatic quadrupole-quadrupole interaction are small. Over a 20 mT magnetic field range, we predict about 10 Feshbach resonances and show that the resonance locations depend on the dysprosium isotope.
我们探索了超冷高磁场淹没壳层 dysprosium 原子在其最低能量磁亚层中的碰撞中的费什巴赫共振的各向异性，这种碰撞只能由于与旋转束缚态的耦合而发生。这与经过充分研究的碱金属原子碰撞形成鲜明对比，在碱金属原子碰撞中，最宽（最强）的费什巴赫共振是由于无旋转束缚态和超精细诱导而产生的。我们对这些自旋极化玻色 dysprosium 原子之间的碰撞进行的第一性原理耦合通道计算揭示了色散和磁偶极-偶极相互作用中的各向异性之间的强烈相互作用。这种各向异性在碱金属和铬的碰撞中是不存在的。我们表明，这两种各向异性都显著影响了作为外加磁场函数的费什巴赫谱。静电四极-四极相互作用的影响很小。在 20 mT 的磁场范围内，我们预测了大约 10 个费什巴赫共振，并表明共振位置取决于 dysprosium 同位素。
