Coupling a single electron to a Bose-Einstein condensate
Coupling a single electron to a Bose-Einstein condensate
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DOI：
10.1038/nature12592
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发表时间：
2013-10-31
期刊：
影响因子：
64.8
通讯作者：
Pfau, Tilman
中科院分区：
文献类型：
--
作者：
Balewski, Jonathan B.;Krupp, Alexander T.;Pfau, Tilman
电子与物质的耦合是我们理解材料性质（如电导率）的核心。电子-声子耦合可以导致两个排斥电子形成库珀对，这形成了Bardeen-库珀-Schrieffer超导性的基础（1）。在这里，我们研究了单个局域电子与玻色-爱因斯坦凝聚体的相互作用，并表明电子可以激发声子，并最终引发整个凝聚体的集体振荡。我们发现，由于更有利的质量比，与离子杂质相比，耦合是令人惊讶的强。电子被一个带电荷的离子核固定，形成里德伯束缚态。这个里德伯电子由一个扩展到8微米大小的波函数来描述，与凝聚体的尺寸相当。在这种状态下，对应于主量子数n = 202，里德伯电子与其轨道内包含的数万个凝聚原子相互作用。我们观察到令人惊讶的长寿命和有限的尺寸效应所造成的电子探索冷凝物的外部区域。我们预计未来的电子轨道成像实验、单电子声子介导耦合的研究以及在量子光学中的应用。
The coupling of electrons to matter lies at the heart of our understanding of material properties such as electrical conductivity. Electron-phonon coupling can lead to the formation of a Cooper pair out of two repelling electrons, which forms the basis for Bardeen-Cooper-Schrieffer superconductivity(1). Here we study the interaction of a single localized electron with a Bose-Einstein condensate and show that the electron can excite phonons and eventually trigger a collective oscillation of the whole condensate. We find that the coupling is surprisingly strong compared to that of ionic impurities, owing to the more favourable mass ratio. The electron is held in place by a single charged ionic core, forming a Rydberg bound state. This Rydberg electron is described by a wavefunction extending to a size of up to eight micrometres, comparable to the dimensions of the condensate. In such a state, corresponding to a principal quantum number of n = 202, the Rydberg electron is interacting with several tens of thousands of condensed atoms contained within its orbit. We observe surprisingly long lifetimes and finite size effects caused by the electron exploring the outer regions of the condensate. We anticipate future experiments on electron orbital imaging, the investigation of phonon-mediated coupling of single electrons, and applications in quantum optics.