Cragg George E, Kerman Arthur K
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, USA.
Phys Rev Lett. 2005 May 20;94(19):190402. doi: 10.1103/PhysRevLett.94.190402. Epub 2005 May 19.
We explore the zero-temperature statics of an atomic Bose-Einstein condensate in which a Feshbach resonance creates a coupling to a second condensate component of quasibound molecules. Using a variational procedure to find the equation of state, the appearance of this binding is manifest in a collapsing ground state, where only the molecular condensate is present up to some critical density. Further, an excited state is seen to reproduce the usual low-density atomic condensate behavior in this system, but the molecular component is found to produce a coherent, many-body decay, quantified by the imaginary part of the chemical potential. Most importantly, the unique decay rate dependencies on density (approximately rho (3/2)) and on scattering length (approximately (5/2)) can be measured in experimental tests of this result.
我们研究了一种原子玻色-爱因斯坦凝聚体的零温静力学，其中费什巴赫共振产生了与准束缚分子的第二个凝聚体组分的耦合。通过变分法来求解状态方程，这种束缚的出现表现为基态坍缩，在达到某个临界密度之前，仅存在分子凝聚体。此外，在该系统中可以看到一个激发态重现了通常的低密度原子凝聚体行为，但发现分子组分产生了一种由化学势的虚部量化的相干多体衰变。最重要的是，在该结果的实验测试中可以测量到独特的衰变率对密度（近似为ρ^(3/2)）和散射长度（近似为(5/2)）的依赖关系。
