Observation of a bilayer superfluid with interlayer coherence

Abstract Controlling the coupling between different degrees of freedom in many-body systems is a powerful technique for engineering novel phases of matter. We create a bilayer system of two-dimensional (2D) ultracold Bose gases and demonstrate the controlled generation of bulk coherence through tuna...

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Main Authors: Erik Rydow, Vijay Pal Singh, Abel Beregi, En Chang, Ludwig Mathey, Christopher J. Foot, Shinichi Sunami
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-62277-w
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author Erik Rydow
Vijay Pal Singh
Abel Beregi
En Chang
Ludwig Mathey
Christopher J. Foot
Shinichi Sunami
author_facet Erik Rydow
Vijay Pal Singh
Abel Beregi
En Chang
Ludwig Mathey
Christopher J. Foot
Shinichi Sunami
author_sort Erik Rydow
collection DOAJ
description Abstract Controlling the coupling between different degrees of freedom in many-body systems is a powerful technique for engineering novel phases of matter. We create a bilayer system of two-dimensional (2D) ultracold Bose gases and demonstrate the controlled generation of bulk coherence through tunable interlayer Josephson coupling. We probe the resulting correlation properties of both phase modes of the bilayer system: the symmetric phase mode is studied via a noise-correlation method, while the antisymmetric phase fluctuations are directly captured by matter-wave interferometry. The measured correlation functions for both of these modes exhibit a crossover from short-range to quasi-long-range order above a coupling-dependent critical point, thus providing direct evidence of bilayer superfluidity mediated by interlayer coupling. We map out the phase diagram and interpret it with renormalization-group theory and Monte Carlo simulations. Additionally, we elucidate the underlying mechanism through the observation of suppressed vortex excitations in the antisymmetric mode.
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issn 2041-1723
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publishDate 2025-08-01
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series Nature Communications
spelling doaj-art-28c7a26effa942e09bba540f3fe1e2ca2025-08-20T03:42:55ZengNature PortfolioNature Communications2041-17232025-08-011611910.1038/s41467-025-62277-wObservation of a bilayer superfluid with interlayer coherenceErik Rydow0Vijay Pal Singh1Abel Beregi2En Chang3Ludwig Mathey4Christopher J. Foot5Shinichi Sunami6Clarendon Laboratory, University of OxfordQuantum Research Centre, Technology Innovation InstituteClarendon Laboratory, University of OxfordClarendon Laboratory, University of OxfordZentrum für Optische Quantentechnologien and Institut für Quantenphysik, Universität HamburgClarendon Laboratory, University of OxfordClarendon Laboratory, University of OxfordAbstract Controlling the coupling between different degrees of freedom in many-body systems is a powerful technique for engineering novel phases of matter. We create a bilayer system of two-dimensional (2D) ultracold Bose gases and demonstrate the controlled generation of bulk coherence through tunable interlayer Josephson coupling. We probe the resulting correlation properties of both phase modes of the bilayer system: the symmetric phase mode is studied via a noise-correlation method, while the antisymmetric phase fluctuations are directly captured by matter-wave interferometry. The measured correlation functions for both of these modes exhibit a crossover from short-range to quasi-long-range order above a coupling-dependent critical point, thus providing direct evidence of bilayer superfluidity mediated by interlayer coupling. We map out the phase diagram and interpret it with renormalization-group theory and Monte Carlo simulations. Additionally, we elucidate the underlying mechanism through the observation of suppressed vortex excitations in the antisymmetric mode.https://doi.org/10.1038/s41467-025-62277-w
spellingShingle Erik Rydow
Vijay Pal Singh
Abel Beregi
En Chang
Ludwig Mathey
Christopher J. Foot
Shinichi Sunami
Observation of a bilayer superfluid with interlayer coherence
Nature Communications
title Observation of a bilayer superfluid with interlayer coherence
title_full Observation of a bilayer superfluid with interlayer coherence
title_fullStr Observation of a bilayer superfluid with interlayer coherence
title_full_unstemmed Observation of a bilayer superfluid with interlayer coherence
title_short Observation of a bilayer superfluid with interlayer coherence
title_sort observation of a bilayer superfluid with interlayer coherence
url https://doi.org/10.1038/s41467-025-62277-w
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