论文标题
棕褐色的两体接触在平面玻色气中：实验与理论
Tan's two-body contact in a planar Bose gas: experiment vs theory
论文作者
论文摘要
我们使用非扰动功能重新归一化组确定了由横向谐波电位限制的平面bose气体中的两体接触。我们使用接触的三维热力学定义，其中后者与玻色子的三维散射长度相对于准二维系统的压力的推导而言。没有任何免费参数，我们发现与Zou {\ it等}的实验数据[nat。通讯。 {\ bf 12}，760（2021）]从低温到高温，包括berezinskii-kosterlitz的附近 - 无与伦比的过渡。我们还表明，成对分布函数的短途行为和动量分布的高摩托车行为由两个接触确定：长度尺度小于特征长度$ \ ell_z = \ ell_z = \ sqrt {\ hbar/mΩ_z_z} $的三维接触量表，与$ \ ell tworty相关的$ \ \ e \ e \ e \ \ \ e \ e \ \ ^ scalimenty的三维范围。一个按几何因素取决于$ \ ell_z $。
We determine the two-body contact in a planar Bose gas confined by a transverse harmonic potential, using the nonperturbative functional renormalization group. We use the three-dimensional thermodynamic definition of the contact where the latter is related to the derivation of the pressure of the quasi-two-dimensional system with respect to the three-dimensional scattering length of the bosons. Without any free parameter, we find a remarkable agreement with the experimental data of Zou {\it et al.} [Nat. Comm. {\bf 12}, 760 (2021)] from low to high temperatures, including the vicinity of the Berezinskii-Kosterlitz-Thouless transition. We also show that the short-distance behavior of the pair distribution function and the high-momentum behavior of the momentum distribution are determined by two contacts: the three-dimensional contact for length scales smaller than the characteristic length $\ell_z=\sqrt{\hbar/mω_z}$ of the harmonic potential and, for length scales larger than $\ell_z$, an effective two-dimensional contact, related to the three-dimensional one by a geometric factor depending on $\ell_z$.
