Density and spin response functions in ultracold fermionic atom gases

Abstract

We propose a new method of detecting the onset of superfluidity in a two-component ultracold fermionic gas of atoms governed by an attractive short-range interaction. By studying the two-body correlation functions we find that a measurement of the momentum distribution of the density and spin response functions allows one to access separately the normal and anomalous densities. The change in sign at low momentum transfer of the density response function signals the transition between a BEC and a BCS regimes, characterized by small and large pairs, respectively. This change in sign of the density response function represents an unambiguous signature of the BEC to BCS crossover. Also, we predict spin rotational symmetry-breaking in this system.

References in corpus (18)

• Observation of resonance condensation of fermionic atom pairs
• Condensation of Pairs of Fermionic Atoms Near a Feshbach Resonance
• Observation of Bose-Einstein Condensation of Molecules
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Experimental Study of the BEC-BCS Crossover Region in Lithium 6
• Bragg spectroscopy of a Bose-Einstein condensate
• Evidence for Superfluidity in a Resonantly Interacting Fermi Gas
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Probing many-body states of ultra-cold atoms via noise correlations
• Excitation of phonons in a Bose-Einstein condensate by light scattering
• The Excitation Spectrum of a Bose-Einstein Condensate
• Phase Fluctuations and Pseudogap Phenomena
• Direct extraction of the Eliashberg function for electron-phonon coupling: A case study of Be(1010)
• Spectroscopy of Superfluid Pairing in Atomic Fermi Gases
• BCS-BEC crossover with a finite-range interaction
• Detection of BCS pairing in neutral Fermi fluids via Stokes scattering: the Hebel Slichter effect
• Fermion-mediated BCS-BEC Crossover in Ultracold Potassium-40 Gases

Cited by in corpus (10)

• Quantum Non-Demolition Detection of Strongly Correlated Systems
• Bragg Spectroscopy of Cold Atomic Fermi Gases
• Relativistic description of BCS-BEC crossover in nuclear matter
• BCS-BEC crossover in nuclear matter with the relativistic Hartree-Bogoliubov theory
• Spin noise spectroscopy to probe quantum states of ultracold fermionic atomic gases
• Correlation functions for a di-neutron condensate in asymmetric nuclear matter
• Dineutron correlations and BCS-BEC crossover in nuclear matter with the Gogny pairing force
• Fundamental Constraints on Linear Response Theories of Fermi Superfluids Above and Below $T_c$
• Two-body correlation functions in nuclear matter with $np$ condensate
• Acoustic attenuation rate in the Fermi-Bose model with a finite-range fermion-fermion interaction