Odd-parity effect and scale-dependent viscosity in atomic quantum gases

Abstract Two-dimensional electron gases are predicted to possess an anomalous “tomographic” transport regime that is marked by an odd-even effect in the relaxation times, with odd-parity deformations of the Fermi surface becoming long-lived in comparison to even-parity ones. In this work, we establi...

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Main Authors: Jeff Maki, Ulf Gran, Johannes Hofmann
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-025-02231-w
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author Jeff Maki
Ulf Gran
Johannes Hofmann
author_facet Jeff Maki
Ulf Gran
Johannes Hofmann
author_sort Jeff Maki
collection DOAJ
description Abstract Two-dimensional electron gases are predicted to possess an anomalous “tomographic” transport regime that is marked by an odd-even effect in the relaxation times, with odd-parity deformations of the Fermi surface becoming long-lived in comparison to even-parity ones. In this work, we establish that neutral two-component atomic Fermi gases also exhibit this tomographic effect. By diagonalizing the Fermi liquid collision integral, we identify odd-parity modes with anomalously long lifetimes below temperatures T≤0.15T F , which is within reach of cold atom experiments. Furthermore, in contrast to electron gases, we find that the odd-even effect in neutral gases is widely tuneable with interactions along the BCS-BEC crossover and is suppressed on the BEC side. We propose as an experimental signature of the odd-even effect the damping rate of quadrupole oscillations, which is anomalously enhanced due to the presence of long-lived odd-parity modes. Our findings suggest that the dynamics of two-dimensional Fermi gases is richer than previously thought and should include additional long-lived modes.
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spelling doaj-art-a69e4b165e5e40f6b29f2bba54f2a6102025-08-20T03:43:11ZengNature PortfolioCommunications Physics2399-36502025-08-01811710.1038/s42005-025-02231-wOdd-parity effect and scale-dependent viscosity in atomic quantum gasesJeff Maki0Ulf Gran1Johannes Hofmann2Department of Physics, University of KonstanzDepartment of Physics, Chalmers University of TechnologyDepartment of Physics, Gothenburg UniversityAbstract Two-dimensional electron gases are predicted to possess an anomalous “tomographic” transport regime that is marked by an odd-even effect in the relaxation times, with odd-parity deformations of the Fermi surface becoming long-lived in comparison to even-parity ones. In this work, we establish that neutral two-component atomic Fermi gases also exhibit this tomographic effect. By diagonalizing the Fermi liquid collision integral, we identify odd-parity modes with anomalously long lifetimes below temperatures T≤0.15T F , which is within reach of cold atom experiments. Furthermore, in contrast to electron gases, we find that the odd-even effect in neutral gases is widely tuneable with interactions along the BCS-BEC crossover and is suppressed on the BEC side. We propose as an experimental signature of the odd-even effect the damping rate of quadrupole oscillations, which is anomalously enhanced due to the presence of long-lived odd-parity modes. Our findings suggest that the dynamics of two-dimensional Fermi gases is richer than previously thought and should include additional long-lived modes.https://doi.org/10.1038/s42005-025-02231-w
spellingShingle Jeff Maki
Ulf Gran
Johannes Hofmann
Odd-parity effect and scale-dependent viscosity in atomic quantum gases
Communications Physics
title Odd-parity effect and scale-dependent viscosity in atomic quantum gases
title_full Odd-parity effect and scale-dependent viscosity in atomic quantum gases
title_fullStr Odd-parity effect and scale-dependent viscosity in atomic quantum gases
title_full_unstemmed Odd-parity effect and scale-dependent viscosity in atomic quantum gases
title_short Odd-parity effect and scale-dependent viscosity in atomic quantum gases
title_sort odd parity effect and scale dependent viscosity in atomic quantum gases
url https://doi.org/10.1038/s42005-025-02231-w
work_keys_str_mv AT jeffmaki oddparityeffectandscaledependentviscosityinatomicquantumgases
AT ulfgran oddparityeffectandscaledependentviscosityinatomicquantumgases
AT johanneshofmann oddparityeffectandscaledependentviscosityinatomicquantumgases