Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations

article Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations published yes Giacomo Bighin author 4CA96FD4-F248-11E8-B48F-1D18A9856A870000-0001-8823-9777 Alberto Cappellaro author 9d13b3cb-30a2-11eb-80dc-f772505e86600000-0001-6110-2359 L. Salasnich author MiLe department We compare recent experimental results [Science 375, 528 (2022)] of the superfluid unitary Fermi gas near the critical temperature with a thermodynamic model based on the elementary excitations of the system. We find good agreement between experimental data and our theory for several quantities such as first sound, second sound, and superfluid fraction. We also show that mode mixing between first and second sound occurs. Finally, we characterize the response amplitude to a density perturbation: Close to the critical temperature both first and second sound can be excited through a density perturbation, whereas at lower temperatures only the first sound mode exhibits a significant response. American Physical Society2022 eng Physical Review A 2469-9926 2469-9934 2206.03924 00082975850001010.1103/PhysRevA.105.063329 1056 Bighin G, Cappellaro A, Salasnich L. Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations. Physical Review A. 2022;105(6). doi:<a href="https://doi.org/10.1103/PhysRevA.105.063329">10.1103/PhysRevA.105.063329</a> G. Bighin, A. Cappellaro, and L. Salasnich, “Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations,” Physical Review A, vol. 105, no. 6. American Physical Society, 2022. Bighin G, Cappellaro A, Salasnich L. 2022. Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations. Physical Review A. 105(6), 063329. Bighin, G., Cappellaro, A., & Salasnich, L. (2022). Unitary Fermi superfluid near the critical temperature: Thermodynamics and sound modes from elementary excitations. Physical Review A. American Physical Society. <a href="https://doi.org/10.1103/PhysRevA.105.063329">https://doi.org/10.1103/PhysRevA.105.063329</a> Bighin, Giacomo, Alberto Cappellaro, and L. Salasnich. “Unitary Fermi Superfluid near the Critical Temperature: Thermodynamics and Sound Modes from Elementary Excitations.” Physical Review A. American Physical Society, 2022. <a href="https://doi.org/10.1103/PhysRevA.105.063329">https://doi.org/10.1103/PhysRevA.105.063329</a>. G. Bighin, A. Cappellaro, L. Salasnich, Physical Review A 105 (2022). Bighin, Giacomo, et al. “Unitary Fermi Superfluid near the Critical Temperature: Thermodynamics and Sound Modes from Elementary Excitations.” Physical Review A, vol. 105, no. 6, 063329, American Physical Society, 2022, doi:<a href="https://doi.org/10.1103/PhysRevA.105.063329">10.1103/PhysRevA.105.063329</a>. 115922022-07-17T22:01:55Z2023-08-03T12:00:11Z