An optical lattice with sound
An optical lattice with sound
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DOI：
10.1038/s41586-021-03945-x
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发表时间：
2021-11-11
期刊：
影响因子：
64.8
通讯作者：
Lev, Benjamin L.
中科院分区：
文献类型：
--
作者：
Guo, Yudan;Kroeze, Ronen M.;Lev, Benjamin L.
量子化的声波-声子-控制着晶体材料的弹性响应，并且在确定它们的热力学性质和电响应方面也起着不可或缺的作用（例如，通过将电子束缚到超导库珀对中）（1-3）。在周期性光势中由中性原子构成的量子固体的模拟器中，晶格声子和弹性的物理学是不存在的：与真实的固体不同，传统的光学晶格是沉默的，因为它们是无限刚性的（4）。因此，晶体的光学晶格实现缺乏一些决定真实的材料低温特性的中心动力学自由度。在这里，我们创建一个光学晶格声子模式使用玻色爱因斯坦凝聚体（BEC）耦合到共焦光学谐振腔。多模腔QED系统扮演着主动量子气体显微镜的角色，它既能使声子成像，又能诱导结晶，从而通过短程光子介导的原子-原子相互作用来支持声子。动态磁化率测量揭示了声子色散关系，表明这些集体激发表现出依赖于BEC-光子耦合强度的声速。我们的结果为探索量子固体中丰富的弹性物理铺平了道路，从量子熔化跃迁（5）到量子区域中的奇异“分形”拓扑缺陷（6）。本文报道的用于捕获玻色-爱因斯坦凝聚体的光学晶格包括光子介导的原子-原子相互作用，该相互作用复制了真实的晶体中的声学模式。
Quantized sound waves-phonons-govern the elastic response of crystalline materials, and also play an integral part in determining their thermodynamic properties and electrical response (for example, by binding electrons into superconducting Cooper pairs)(1-3). The physics of lattice phonons and elasticity is absent in simulators of quantum solids constructed of neutral atoms in periodic light potentials: unlike real solids, traditional optical lattices are silent because they are infinitely stiff(4). Optical-lattice realizations of crystals therefore lack some of the central dynamical degrees of freedom that determine the low-temperature properties of real materials. Here, we create an optical lattice with phonon modes using a Bose-Einstein condensate (BEC) coupled to a confocal optical resonator. Playing the role of an active quantum gas microscope, the multimode cavity QED system both images the phonons and induces the crystallization that supports phonons via short-range, photon-mediated atom-atom interactions. Dynamical susceptibility measurements reveal the phonon dispersion relation, showing that these collective excitations exhibit a sound speed dependent on the BEC-photon coupling strength. Our results pave the way for exploring the rich physics of elasticity in quantum solids, ranging from quantum melting transitions(5) to exotic 'fractonic' topological defects(6) in the quantum regime.An optical lattice for trapping a Bose-Einstein condensate reported here includes photon-mediated atom-atom interactions that replicate acoustic modes in real crystals.