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Main Authors: Fabritius, Philipp, Mohan, Jeffrey, Talebi, Mohsen, Wili, Simon, Zwerger, Wilhelm, Huang, Meng-Zi, Esslinger, Tilman
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2309.04359
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author Fabritius, Philipp
Mohan, Jeffrey
Talebi, Mohsen
Wili, Simon
Zwerger, Wilhelm
Huang, Meng-Zi
Esslinger, Tilman
author_facet Fabritius, Philipp
Mohan, Jeffrey
Talebi, Mohsen
Wili, Simon
Zwerger, Wilhelm
Huang, Meng-Zi
Esslinger, Tilman
contents The nature of particle and entropy flow between two superfluids is often understood in terms of reversible flow carried by an entropy-free, macroscopic wavefunction. While this wavefunction is responsible for many intriguing properties of superfluids and superconductors, its interplay with excitations in non-equilibrium situations is less understood. Here, we observe large concurrent flows of both particles and entropy through a ballistic channel connecting two strongly interacting fermionic superfluids. Both currents respond nonlinearly to chemical potential and temperature biases. We find that the entropy transported per particle is much larger than the prediction of superfluid hydrodynamics in the linear regime and largely independent of changes in the channel's geometry. In contrast, the timescales of advective and diffusive entropy transport vary significantly with the channel geometry. In our setting, superfluidity counterintuitively increases the speed of entropy transport. Moreover, we develop a phenomenological model describing the nonlinear dynamics within the framework of generalised gradient dynamics. Our approach for measuring entropy currents may help elucidate mechanisms of heat transfer in superfluids and superconducting devices.
format Preprint
id arxiv_https___arxiv_org_abs_2309_04359
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Irreversible entropy transport enhanced by fermionic superfluidity
Fabritius, Philipp
Mohan, Jeffrey
Talebi, Mohsen
Wili, Simon
Zwerger, Wilhelm
Huang, Meng-Zi
Esslinger, Tilman
Quantum Gases
Superconductivity
Atomic Physics
The nature of particle and entropy flow between two superfluids is often understood in terms of reversible flow carried by an entropy-free, macroscopic wavefunction. While this wavefunction is responsible for many intriguing properties of superfluids and superconductors, its interplay with excitations in non-equilibrium situations is less understood. Here, we observe large concurrent flows of both particles and entropy through a ballistic channel connecting two strongly interacting fermionic superfluids. Both currents respond nonlinearly to chemical potential and temperature biases. We find that the entropy transported per particle is much larger than the prediction of superfluid hydrodynamics in the linear regime and largely independent of changes in the channel's geometry. In contrast, the timescales of advective and diffusive entropy transport vary significantly with the channel geometry. In our setting, superfluidity counterintuitively increases the speed of entropy transport. Moreover, we develop a phenomenological model describing the nonlinear dynamics within the framework of generalised gradient dynamics. Our approach for measuring entropy currents may help elucidate mechanisms of heat transfer in superfluids and superconducting devices.
title Irreversible entropy transport enhanced by fermionic superfluidity
topic Quantum Gases
Superconductivity
Atomic Physics
url https://arxiv.org/abs/2309.04359