Exploring emergent heterogeneous phases in strongly repulsive Fermi gases
Name
PhysRevA.101.013603.pdf
Description
Published version
Size
1.14 MB
Format
Adobe PDF
Checksum (MD5)
fc49b55a2f642b03ae5cabeecafebba6
Author(s)
Scazza, F
Valtolina, G
Amico, A
Tavares, PES
Inguscio, M
Ketterle, W
Roati, G
Zaccanti, M
Date Issued
2020
Journal
Physical Review A
Publisher
American Physical Society (APS)
Version
Final published version
Abstract
© 2020 American Physical Society. 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)PRLTAO0031-900710.1103/PhysRevLett.121.253602]. 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.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT-Harvard Center for Ultracold Atoms
Massachusetts Institute of Technology. Research Laboratory of Electronics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PhysRevA.101.013603
