Observation of Quasiparticle Pair Production and Quantum Entanglement in Atomic Quantum Gases Quenched to an Attractive Interaction
Observation of Quasiparticle Pair Production and Quantum Entanglement in Atomic Quantum Gases Quenched to an Attractive Interaction
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DOI：
10.1103/physrevlett.127.060404
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发表时间：
2021-08-06
影响因子：
8.6
通讯作者：
Hung, Chen-Lung
中科院分区：
文献类型：
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作者：
Chen, Cheng-An;Khlebnikov, Sergei;Hung, Chen-Lung
我们报告了原子超流体中调制不稳定性产生准粒子对的观察结果，并提出了一种测量技术，可以直接表征准粒子量子纠缠。通过将原子相互作用猝灭为吸引，然后再回到弱排斥，我们产生了相关的准粒子，并通过评估原位密度噪声功率谱来监测它们在超流体中的演变，该功率谱本质上是测量基态原子和具有相反动量的准粒子之间的“同差”干涉。我们观察到功率谱的大幅增长和随后在我们的分辨率限制内的宽空间频带内的相干振荡，证明了相干准粒子的产生和演化。观测到光谱在连续变量态的Peres-Horodecki可分性准则设定的量子极限下振荡，从而证实了相互作用猝灭诱导的准粒子之间存在量子纠缠。
We report observations of quasiparticle pair production by a modulational instability in an atomic superfluid and present a measurement technique that enables direct characterization of quasiparticle quantum entanglement. By quenching the atomic interaction to attractive and then back to weakly repulsive, we produce correlated quasiparticles and monitor their evolution in a superfluid through evaluating the in situ density noise power spectrum, which essentially measures a "homodyne" interference between ground-state atoms and quasiparticles of opposite momenta. We observe large amplitude growth in the power spectrum and subsequent coherent oscillations in a wide spatial frequency band within our resolution limit, demonstrating coherent quasiparticle generation and evolution. The spectrum is observed to oscillate below a quantum limit set by the Peres-Horodecki separability criterion of continuous-variable states, thereby confirming quantum entanglement between interaction quench-induced quasiparticles.