Braaten Eric, Hammer H-W, Mehen Thomas
Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
Phys Rev Lett. 2002 Jan 28;88(4):040401. doi: 10.1103/PhysRevLett.88.040401. Epub 2002 Jan 8.
We study a dilute Bose gas of atoms whose scattering length a is large compared to the range of their interaction. We calculate the energy density E of a homogeneous Bose-Einstein condensate (BEC) to second order in the low-density expansion, expressing it in terms of a and a second parameter Lambda* that determines the low-energy observables in the three-body sector. The second-order correction to E has a small imaginary part that reflects the instability due to three-body recombination. In the case of a trapped BEC with large negative a, we calculate the coefficient of the three-body mean-field term in E in terms of a and Lambda*. It can be very large if there is an Efimov state near threshold.
我们研究了一种稀薄的玻色原子气体，其散射长度a与相互作用范围相比很大。我们在低密度展开中计算了均匀玻色 - 爱因斯坦凝聚体（BEC）的能量密度E到二阶，用a和第二个参数Λ来表示它，Λ决定了三体部分的低能可观测量。E的二阶修正有一个小的虚部，它反映了由于三体复合导致的不稳定性。在具有大的负a的捕获BEC的情况下，我们根据a和Λ*计算了E中三体平均场项的系数。如果在阈值附近存在埃菲莫夫态，它可能会非常大。
