Understanding the effect of interactions in the phase evolution of expanding atomic Bose Einstein condensates is fundamental to describe the basic phenomenon of matter wave interference. Many theoretical and experimental works tackled this problem, always with the implicit assumption that the mutual interaction between two expanding condensates rigidly modifies the phase evolution through an effective force. In this paper, we present a combined experimental and theoretical investigation of the interference profile of expanding ${}^{87}$Rb condensates, with a specific focus on the effect of interactions. We come to the different conclusion that the mutual interaction produces local modifications of the condensate phase only in the region where the wavepackets overlap.

中文翻译：

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相互作用对玻色-爱因斯坦凝聚物干涉图样的影响

了解相互作用对原子膨胀玻色爱因斯坦凝聚物的相演化的影响是描述物质波干扰的基本现象的基础。许多理论和实验工作都用一个隐含的假设来解决这个问题，即两个膨胀的冷凝物之间的相互作用会通过有效力严格地改变相的演变。在本文中，我们将对扩展干扰的分布进行实验和理论研究相结合${}^{87}$Rb冷凝，特别着重于相互作用的影响。我们得出不同的结论，即相互作用仅在波包重叠的区域内产生凝结相的局部变化。