Observation of quantum-limited spin transport in strongly interacting two-dimensional fermi gases
We measure the transport properties of two-dimensional ultracold Fermi gases during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we are able to distinguish bare spin diffusion from the Leggett-Rice effect, in which demagnetization is slowed by t...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
31 March 2017
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| In: |
Physical review letters
Year: 2017, Volume: 118, Issue: 13 |
| ISSN: | 1079-7114 |
| DOI: | 10.1103/PhysRevLett.118.130405 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1103/PhysRevLett.118.130405 Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevLett.118.130405 
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| Author Notes: | C. Luciuk, S. Smale, F. Böttcher, H. Sharum, B. A. Olsen, S. Trotzky, T. Enss and J. H. Thywissen |
| Summary: | We measure the transport properties of two-dimensional ultracold Fermi gases during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we are able to distinguish bare spin diffusion from the Leggett-Rice effect, in which demagnetization is slowed by the precession of a spin current around the local magnetization. When the two-dimensional scattering length is tuned to be comparable to the inverse Fermi wave vector k−1F, we find that the bare transverse spin diffusivity reaches a minimum of 1.7(6)ℏ/m, where m is the bare particle mass. The rate of demagnetization is also reflected in the growth rate of the s-wave contact, observed using time-resolved spectroscopy. The contact rises to 0.28(3)k2F per particle, which quantifies how scaling symmetry is broken by near-resonant interactions, unlike in unitary three-dimensional systems. Our observations support the conjecture that, in systems with strong scattering, the local relaxation rate is bounded from above by kBT/ℏ. |
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| Item Description: | Gesehen am 23.11.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1079-7114 |
| DOI: | 10.1103/PhysRevLett.118.130405 |