Exploring emergent heterogeneous phases in strongly repulsive Fermi gases
Year: 2020
Authors: Scazza F., Valtolina G., Amico A., Tavares PES, Inguscio M., Ketterle W., Roati G., Zaccanti M.
Autors Affiliation: CNR, INO, I-50019 Sesto Fiorentino, Italy; Univ Firenze, European Lab Nonlinear Spect LENS, I-50019 Sesto Fiorentino, Italy; Univ Colorado, JILA, Boulder, CO 80309 USA; Univ Firenze, Dipartimento Fis & Astron, I-50019 Sesto Fiorentino, Italy; Univ Fed Minas Gerais, Dept Fis, BR-31270901 Belo Horizonte, MG, Brazil; Univ Rome, Dept Engn, Campus Biomed, I-00128 Rome, Italy; MIT, Dept Phys, Harvard Ctr Ultracold Atoms, Cambridge, MA 02139 USA; MIT, Res Lab Elect, Cambridge, MA 02139 USA.
Abstract: Recent experiments have revitalized the interest in a Fermi gas of ultracold atoms with strong repulsive interactions. In spite of its seeming simplicity, this system exhibits a complex behavior, resulting from the competing action of two distinct instabilities: ferromagnetism, which promotes spin anticorrelations and domain formation; and pairing, which renders the repulsive fermionic atoms unstable toward forming weakly bound bosonic molecules. The breakdown of the homogeneous repulsive Fermi liquid arising from such concurrent mechanisms has been recently observed in real time through pump-probe spectroscopic techniques [A. Amico et al., Phys. Rev. Lett. 121. 253602 (2018)]. These studies also lead to the discovery of an emergent metastable many-body state, an unpredicted quantum emulsion of anticorrelated fermions and pairs. Here, we investigate in detail the properties of such an exotic regime by studying the evolution of kinetic and release energies, the spectral response and coherence of the unpaired fermionic population, and its spin-density noise correlations. All our observations consistently point to a low-temperature heterogeneous phase, where paired and unpaired fermions macroscopically coexist while featuring microscale phase separation. Our findings open appealing avenues for the exploration of quantum emulsions and also possibly of inhomogeneous superfluid regimes, where pair condensation may coexist with magnetic order
Journal/Review: PHYSICAL REVIEW A
Volume: 101 (1) Pages from: 13603-1 to: 13603-12
More Information: We acknowledge insightful discussions with Stefano Giorgini, Dmitry Petrov, and Alessio Recati. Special thanks to the LENS Quantum Gases group. This work was supported under European Research Council Grants No. 637738 PoLiChroM and No. 307032 QuFerm2D, and European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 705269.KeyWords: ULTRACOLD GASES, FERMI GASES, FERROMAGNETISM, DOMAIN FORMATION, HETEROGENEOUS PHASEDOI: 10.1103/PhysRevA.101.013603ImpactFactor: 3.140Citations: 11data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-09-15References taken from IsiWeb of Knowledge: (subscribers only)
