We study the ground state quantum fragmentation in a mixture of a polar condensate and a ferromagnetic condensate when subject to an external magnetic field. We pay more attentions to the polar condensate and find that it will be less fragile in the mixture when perturbed by the magnetic field. Both atom numbers and the number fluctuations in the spin-0 component will keep in a high magnitude of order of $N$ when the magnetization of the system is increased. The role of the ferromagnetic condensate is to provide a uniform and stable background which can delay the rapid shrink of the 0-component population and make it possible to capture the \textquotedblleft super-fragmentation \textquotedblright. Our method has potential applications in measuring the inter-species spin-coupling interaction through adjusting the magnetic field.
In a mixture of two kinds of identical bosons there are two types of pairs, identical bosons' pairs, of either species, and pairs of distinguishable bosons. In the present work fragmentation of pairs in a trapped mixture of Bose-Einstein condensate is investigated using a solvable model, the symmetric harmonic-interaction model for mixtures. The natural geminals for pairs made of identical or distinguishable bosons are explicitly contracted by diagonalizing the intra-species and inter-species reduced two-particle density matrices, respectively. Properties of pairs' fragmentation in the mixture…
Spin-1 Bose gases quenched to spin degeneracy exhibit fragmentation: the appearance of a condensate in more than one single-particle state. Due to its highly entangled nature, the dynamics leading to this collective state are beyond the scope of a Gaussian variational approximation of the many-body wave function. Here, we improve the performance of the Gaussian variational Ansatz by considering dissipation into a fictitious environment, effectively suppressing entanglement within individual quantum trajectories at the expense of introducing a classical mixture of states. We find that this quan…
Emergence of magnetic excitations in one-dimensional quantum mixtures under confinement
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales（布宜诺斯艾利斯大学，精确与自然科学学院）；CONICET - Universidad de Buenos Aires, Instituto de Física de Buenos Aires (IFIBA)（阿根廷国家科学研究委员会-布宜诺斯艾利斯大学，布宜诺斯艾利斯物理研究所）；Université Côte d’Azur, CNRS, Institut de Physique de Nice（蔚蓝海岸大学，法国国家科学研究中心，尼斯物理研究所）；Institut Universitaire de France（法兰西学院）；Université Grenoble Alpes, CNRS, LPMMC（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，极低温与强磁场中心）
We report on the observation of heteronuclear magnetic Feshbach resonances in several isotope mixtures of the highly magnetic elements erbium and dysprosium. Among many narrow features, we identify two resonances with a width greater than one Gauss. We characterize one of these resonances, in a mixture of $^{168}$Er and $^{164}$Dy, in terms of loss rates and elastic cross section, and observe a temperature dependence of the on-resonance loss rate suggestive of a universal scaling associated with broad resonances. Our observations hold promise for the use of such a resonance for tuning the inte…
Thermalization measurements on an ultracold mixture of metastable $^4$He and $^{87}$Rb atoms in a quadrupole magnetic trap
最近，我们报道了（Knoop等人[arXiv：1404.4826]）通过在四极磁阱中对超冷混合物进行热化测量，实验测定亚稳态三重态$^4$ He+ $^{87}$ Rb散射长度。在这里，我们提出了我们的实验装置，并详细说明这些热化测量。特别地，我们给出了四极磁阱种间热化率的理论描述。e.在Majorana加热的存在下，和一个通用的程序来提取散射长度从弹性截面在有限温度下的$C_6$系数的知识的基础上单独。此外，从我们的热化数据中，我们得到了一个上限的总种间两体损失率系数$1.5\times 10^{-12}$ cm $^3$ s $^{-1}$。
Magnetic control of ultra-cold $^6$Li and $^{174}$Yb($^3P_2$) atom mixtures with Feshbach resonances
从理论上研究了在玻色子亚稳$^{174}$ Yb（$^3$ P $_2$）原子与费米$^6$ Li原子碰撞中形成磁调谐Feshbach分子的可行性.与碱金属原子碰撞相比，亚稳原子碰撞具有高度的各向异性。我们的第一原理耦合通道计算这些碰撞揭示了广泛的费什巴赫共振的存在，由于各向异性的分子和原子的超精细相互作用的综合影响。为了使我们的预测符合实验观察到的宽共振结构\cite{Deep2015}的具体位置，我们通过直接最小二乘拟合优化了短程势的形状。这使我们能够确定其领先的角动量量子数的主导共振和描述的作用，碰撞各向异性的创建和扩大这个和其他共振。
