Quench-induced spontaneous currents in rings of ultracold fermionic atoms
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arXiv
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| Format: | Preprint |
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2023
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| _version_ | 1866929367389569024 |
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| author | Allman, Daniel G. Sabharwal, Parth Wright, Kevin C. |
| author_facet | Allman, Daniel G. Sabharwal, Parth Wright, Kevin C. |
| contents | We have observed the spontaneous appearance of currents in a ring of ultracold fermionic atoms (6Li) with attractive interactions, following a quench to a BCS-like pair superfluid. We have measured the winding number probability distribution for a range of quench rates, with a quench protocol using simultaneous forced evaporation and interaction ramps to achieve faster effective quench rates with less atom loss than a purely evaporative quench. We find that for the fastest quenches the mean square winding number of the current follows a scaling law in the quench rate with exponent σ = 0.24(2), which is somewhat lower than that predicted by the Kibble-Zurek mechanism (KZM) for the three-dimensional XY model (1/3), and unexpectedly closer to the value obtained from mean-field theory (1/4). For slower quenches non-universal effects become significant, and we observe a lower rate of spontaneous current formation that does not follow a simple scaling law. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_15348 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Quench-induced spontaneous currents in rings of ultracold fermionic atoms Allman, Daniel G. Sabharwal, Parth Wright, Kevin C. Quantum Gases We have observed the spontaneous appearance of currents in a ring of ultracold fermionic atoms (6Li) with attractive interactions, following a quench to a BCS-like pair superfluid. We have measured the winding number probability distribution for a range of quench rates, with a quench protocol using simultaneous forced evaporation and interaction ramps to achieve faster effective quench rates with less atom loss than a purely evaporative quench. We find that for the fastest quenches the mean square winding number of the current follows a scaling law in the quench rate with exponent σ = 0.24(2), which is somewhat lower than that predicted by the Kibble-Zurek mechanism (KZM) for the three-dimensional XY model (1/3), and unexpectedly closer to the value obtained from mean-field theory (1/4). For slower quenches non-universal effects become significant, and we observe a lower rate of spontaneous current formation that does not follow a simple scaling law. |
| title | Quench-induced spontaneous currents in rings of ultracold fermionic atoms |
| topic | Quantum Gases |
| url | https://arxiv.org/abs/2310.15348 |