Observation of Quasiparticle Pair Production and Quantum Entanglement in Atomic Quantum Gases Quenched to an Attractive Interaction

Journal Article · 05 August 2021 · Physical Review Letters

DOI: https://doi.org/10.1103/physrevlett.127.060404 · OSTI ID:1842926

Chen, Cheng-An ^[1]; Khlebnikov, Sergei ^[2]; Hung, Chen-Lung  ^[2]

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1. Purdue Univ., West Lafayette, IN (United States); Purdue University
2. Purdue Univ., West Lafayette, IN (United States)

We report observation of quasiparticle pair-production and characterize quantum entanglement created by a modulational instability in an atomic superfluid. 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. Here, 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.

• Research Organization: Purdue Univ., West Lafayette, IN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0019202
• OSTI ID: 1842926
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 6 Vol. 127; ISSN 0031-9007
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English