We present a theoretical study of the dynamics of a Bose-Einstein condensate (BEC) trapped inside an expanding toroid that can realize an analog inflationary universe. As the system expands, we find that phonons in the BEC undergo redshift and damping due to quantum pressure effects, owing to the thinness of the ring. We predict that rapidly expanding toroidal BEC's can exhibit spontaneous particle creation, and study this phenomenon in the context of an initial coherent state wave function. We show how particle creation would be revealed in the atom density and density correlations, and discuss connections to the cosmological theory of inflation.

中文翻译：

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环形玻色-爱因斯坦冷凝物中的膨胀动力学和颗粒产生

我们提出了对玻色-爱因斯坦凝结水（BEC）的动力学的理论研究，该凝结水被困在一个可以实现模拟膨胀宇宙的膨胀环面内。随着系统的扩展，我们发现由于环的薄度，BEC中的声子由于量子压力效应而经历了红移和阻尼。我们预测快速膨胀的环形BEC会表现出自发的粒子生成，并在初始相干态波函数的背景下研究此现象。我们展示了如何在原子密度和密度相关性中揭示粒子的产生，并讨论了与膨胀学的宇宙学理论的联系。