Theory of Radio Frequency Spectroscopy Experiments in Ultracold Fermi Gases and Their Relation to Photoemission Experiments in the Cuprates

Abstract

In this paper we present an overview of radio frequency (RF) spectroscopy in the atomic Fermi superfluids. An ultimate goal is to suggest new directions in the cold gas research agenda from the condensed matter perspective.Our focus is on the experimental and theoretical literature of cold gases and photoemission spectroscopy of the cuprates particularly as it pertains to areas of overlap. This paper contains a systematic overview of the theory of RF spectroscopy, both momentum integrated and momentum resolved. We discuss the effects of traps, population imbalance, final state interactions over the entire range of temperatures and compare theory and experiment. We show that this broad range of phenomena can be accomodated within the BCS-Leggett description of BCS-BEC crossover and that this scheme also captures some of the central observations in photoemission experiments in the cuprates. In this last context, we note that the key themes which have emerged in cuprate photoemission studies involve characterization of the fermionic self energy, of the pseudogap and of the effects of superconducting coherence (in passing from above to below the superfluid transition temperature, $T_c$).These issues have a counterpart in the cold Fermi gases and it would be most useful in future to use these atomic systems to address these and the more sweeping question of how to describe that anomalous superfluid phase which forms in the presence of a normal state excitation gap.

23 pages, 22 figures

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Cited by in corpus (34)

• Observation of pseudogap behavior in a strongly interacting Fermi gas
• Evolution of the Normal State of a Strongly Interacting Fermi Gas from a Pseudogap Phase to a Molecular Bose Gas
• Comparing and contrasting nuclei and cold atomic gases
• Breakdown of Fermi liquid description for strongly interacting fermions
• Short-Time Operator Product Expansion for rf Spectroscopy of a Strongly-interacting Fermi Gas
• Angle-resolved photoemission spectroscopy with quantum gas microscopes
• Angle-resolved photoemission spectroscopy of a Fermi-Hubbard system
• Pseudogaps in strongly interacting Fermi gases
• High temperature pairing in a strongly interacting two-dimensional Fermi gas
• Comparative Study of BCS-BEC Crossover Theories above $T_c$: the Nature of the Pseudogap in Ultra-Cold Atomic Fermi Gases
• Physics of ultracold Fermi gases revealed by spectroscopies
• Magic-Angle Semimetals with Chiral Symmetry
• Microscopic Approach to Shear Viscosities in Superfluid Gases: From BCS to BEC
• Establishing the Presence of Coherence in Atomic Fermi Superfluids: Spin-Flip and Spin-Preserving Bragg Scattering at Finite Temperatures
• Perfect Fluids and Bad Metals: Transport Analogies Between Ultracold Fermi Gases and High $T_c$ Superconductors
• Pseudogap phenomena in ultracold atomic Fermi gases
• Instability of Fulde-Ferrell-Larkin-Ovchinnikov states in three and two dimensions
• Breakdown of the Fermi polaron description near Fermi degeneracy at unitarity
• Pairing and radio-frequency spectroscopy in two-dimensional Fermi gases
• Local Photoemission Spectra and Effects of Spatial Inhomogeneity in the BCS-BEC Crossover Regime of a Trapped Ultracold Fermi Gas
• Induced p-wave superfluidity in strongly interacting imbalanced Fermi gases
• Momentum-resolved spectroscopy of a Fermi liquid
• Phase diagrams of Fermi gases in a trap with mass and population imbalances at finite temperature
• The Compressibility in Strongly Correlated Superconductors and Superfluids: From BCS to BEC
• Thermodynamic Properties of Rashba Spin-Orbit-Coupled Fermi Gas
• Momentum-resolved Raman spectroscopy of bound molecules in ultracold Fermi gas
• Mean-field description of pairing effects, BKT physics, and superfluidity in 2D Bose gases
• Momentum-resolved Raman spectroscopy of non-interacting ultracold Fermi gas
• Flow equation approach to the linear response theory of superconductors
• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part I: Balanced case
• Effective control of chemical potentials by Rabi coupling with rf-fields in ultracold mixtures
• Universal Signatures of Majorana-like Quasiparticles in Strongly Correlated Landau-Fermi Liquids
• Induced superfluidity of imbalanced Fermi gases near unitarity
• Probing the homogeneous spectral function of a strongly interacting superfluid atomic Fermi gas in a trap using phase separation and momentum resolved rf spectroscopy