How to realize a homogeneous dipolar Bose gas in the roton regime
How to realize a homogeneous dipolar Bose gas in the roton regime
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DOI：
10.1103/physreva.105.l061301
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发表时间：
2021-12
影响因子：
2.9
通讯作者：
P'eter Juh'asz;Milan Krstaji'c;D. Strachan;Edward Gandar;Robert P. Smith
中科院分区：
文献类型：
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作者：
P'eter Juh'asz;Milan Krstaji'c;D. Strachan;Edward Gandar;Robert P. Smith
均质量子气体为研究多体现象开辟了新的可能性，现在已经在各种系统中实现。对于具有短程相互作用的气体，可以预见的是，使云均匀的方法是将其困在理想的(均匀的)盒势中。我们发现，当长程相互作用很重要时，在轻子区域产生接近均匀的偶极气体，实际上需要将粒子捕获在软壁(非均匀)盒状势能中。特别地，我们数值地探索了限制在沿极化轴调和的煎饼陷阱中的偶极气体和径向轴对称的幂函数势。我们发现，中间的p‘S使接近达到轻子区所需的临界密度的样品所占比例最大，而较高的S即使在系统的大部分不处于轻子区时，也会在壁面附近触发密度振荡。我们刻画了最优密度分布如何依赖于俘获势的形状，并发现它受陷阱壁陡度的控制。
Homogeneous quantum gases open up new possibilities for studying many-body phenomena and have now been realised for a variety of systems. For gases with short-range interactions the way to make the cloud homogeneous is, predictably, to trap it in an ideal (homogeneous) box potential. We show that creating a close to homogeneous dipolar gas in the roton regime, when long-range interactions are important, actually requires trapping particles in soft-walled (inhomogeneous) box-like potentials. In particular, we numerically explore a dipolar gas confined in a pancake trap which is harmonic along the polarisation axis and a cylindrically symmetric power-law potential $r^p$ radially. We find that intermediate $p$'s maximise the proportion of the sample that can be brought close to the critical density required to reach the roton regime, whereas higher $p$'s trigger density oscillations near the wall even when the bulk of the system is not in the roton regime. We characterise how the optimum density distribution depends on the shape of the trapping potential and find it is controlled by the trap wall steepness.