Observation of pseudogap behavior in a strongly interacting Fermi gas

Abstract

Ultracold atomic Fermi gases present an opportunity to study strongly interacting Fermi systems in a controlled and uncomplicated setting. The ability to tune attractive interactions has led to the discovery of superfluidity in these systems with an extremely high transition temperature, near T/T_F = 0.2. This superfluidity is the electrically neutral analog of superconductivity; however, superfluidity in atomic Fermi gases occurs in the limit of strong interactions and defies a conventional BCS description. For these strong interactions, it is predicted that the onset of pairing and superfluidity can occur at different temperatures. This gives rise to a pseudogap region where, for a range of temperatures, the system retains some of the characteristics of the superfluid phase, such as a BCS-like dispersion and a partially gapped density of states, but does not exhibit superfluidity. By making two independent measurements: the direct observation of pair condensation in momentum space and a measurement of the single-particle spectral function using an analog to photoemission spectroscopy, we directly probe the pseudogap phase. Our measurements reveal a BCS-like dispersion with back-bending near the Fermi wave vector k_F that persists well above the transition temperature for pair condensation.

References in corpus (24)

• Observation of resonance condensation of fermionic atom pairs
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Large momentum part of fermions with large scattering length
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• Probing the Low-Energy Electronic Structure of Complex Systems by ARPES
• Verification of universal relations in a strongly interacting Fermi gas
• Pseudogap and spectral function from superconducting fluctuations to the bosonic limit
• Determination of the Superfluid Gap in Atomic Fermi Gases by Quasiparticle Spectroscopy
• Spectral Functions and rf Response of Ultracold Fermionic Atoms
• Pseudogap effects induced by resonant pair scattering
• The potential energy of a ${}^{40}$K Fermi gas in the BCS-BEC crossover
• Single-particle properties and pseudogap effects in the BCS-BEC crossover regime of an ultracold Fermi gas above Tc
• Evidence for pairing above Tc from the dispersion in the pseudogap phase of cuprates
• Formation Time of a Fermion Pair Condensate
• The Finite Temperature Pairing Gap of a Unitary Fermi Gas by Quantum Monte Carlo Calculations
• Probing the Spectral Function Using Momentum Resolved Radio Frequency Spectroscopy in Trapped Fermi Gases
• Universal Short-Distance Structure of the Single-Particle Spectral Function of Dilute Fermi Gases
• Twin peaks in rf spectra of Fermi gases at unitarity
• Theory of Radio Frequency Spectroscopy Experiments in Ultracold Fermi Gases and Their Relation to Photoemission Experiments in the Cuprates
• Bragg Spectroscopy of Cold Atomic Fermi Gases
• Extracting the condensate density from projection experiments with Fermi gases
• Probing Fermionic Condensates by Fast-Sweep Projection onto Feshbach Molecules
• Superfluid to insulator phase transition in a unitary Fermi gas

Cited by in corpus (228)

• Revealing the Superfluid Lambda Transition in the Universal Thermodynamics of a Unitary Fermi Gas
• One-Dimensional Quantum Liquids: Beyond the Luttinger Liquid Paradigm
• Polarons, Dressed Molecules, and Itinerant Ferromagnetism in ultracold Fermi gases
• Universal Spin Transport in a Strongly Interacting Fermi Gas
• BCS-BEC Crossover and the Unitary Fermi Gas
• Exceptional rings in two-dimensional correlated systems with chiral symmetry
• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• BCS-BEC Crossover and Topological Phase Transition in 3D Spin-Orbit Coupled Degenerate Fermi Gases
• Observation of a pairing pseudogap in a two-dimensional Fermi gas
• Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
• Probing anisotropic superfluidity of rashbons in atomic Fermi gases
• Quantum gas microscopy for single atom and spin detection
• High Temperature Superfluidity in Double Bilayer Graphene
• General relations for quantum gases in two and three dimensions. Two-component fermions
• Two-terminal transport measurements with cold atoms
• Measurement of the Homogeneous Contact of a Unitary Fermi gas
• Exotic Superconducting States in FeSe-based Materials
• Evolution of the Normal State of a Strongly Interacting Fermi Gas from a Pseudogap Phase to a Molecular Bose Gas
• Fluctuations and phase transitions in Larkin-Ovchinnikov liquid crystal states of population-imbalanced resonant Fermi gas
• Comparing and contrasting nuclei and cold atomic gases
• Gate-controlled BCS-BEC crossover in a two-dimensional superconductor
• Transverse Demagnetization Dynamics of a Unitary Fermi Gas
• Observation of a Transition Between Dynamical Phases in a Quantum Degenerate Fermi Gas
• Virial expansion for a strongly correlated Fermi system and its application to ultracold atomic Fermi gases
• Fermi-Liquid Behavior of the Normal Phase of a Strongly Interacting Gas of Cold Atoms
• Searching for Majorana Fermions in 2D Spin-orbit Coupled Fermi Superfluids at Finite Temperature
• Breakdown of Fermi liquid description for strongly interacting fermions
• Superconductivity in an electron band just above the Fermi level: possible route to BCS-BEC superconductivity
• Spectral response and contact of the unitary Fermi gas
• Superconductivity vs bound state formation in a two-band superconductor with small Fermi energy -- applications to Fe-pnictides/chalcogenides and doped SrTiO3
• Temperature dependence of the contact in a unitary Fermi gas
• Universal equation of state and pseudogap in the two-dimensional Fermi gas
• Momentum Distribution and Contact of the Unitary Fermi gas
• Rashba spin-orbit coupled atomic Fermi gases
• Quantum mechanical limitations to spin diffusion in the unitary Fermi gas
• Quantum vortex core and missing pseudogap in the multi-band BCS-BEC-crossover superconductor FeSe
• Tuning the Tricritical Point with Spin-orbit Coupling in Polarized Fermionic Condensates
• Onset of a Pseudogap Regime in Ultracold Fermi Gases
• Band-edge BCS-BEC crossover in a two-band superconductor: physical properties and detection parameters
• Emergent Novel Metallic State in a Disordered 2D Mott Insulator
• Temperature and coupling dependence of the universal contact intensity for an ultracold Fermi gas
• Magic-angle semimetals
• Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence
• Angle-resolved photoemission spectroscopy of a Fermi-Hubbard system
• Pseudogaps in strongly interacting Fermi gases
• Cooper pairing above the critical temperature in a unitary Fermi gas
• Who is the Lord of the Rings: Majorana, Dirac or Lifshitz? The Spin-Orbit-Zeeman Saga in Ultra-cold Fermions
• Anomalous isotope effect near a 2.5 Lifshitz transition in a multi-band multi-condensate superconductor made of a superlattice of stripes
• Momentum-dependent pseudogaps in the half-filled two-dimensional Hubbard model
• Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Pair Correlations in the Two-Dimensional Fermi Gas
• Spin susceptibility and fluctuation corrections in the BCS-BEC crossover regime of an ultracold Fermi gas
• High temperature pairing in a strongly interacting two-dimensional Fermi gas
• Pairing effects in the normal phase of a two-dimensional Fermi gas
• Density and spin response of a strongly-interacting Fermi gas in the attractive and quasi-repulsive regime
• Low temperature properties of the infinite-dimensional attractive Hubbard model
• Measurement of the Dynamical Structure Factor of a 1D Interacting Fermi Gas
• Superfluid Fermi atomic gas as a quantum simulator for the study of neutron-star equation of state
• Measurement of spectral functions of ultracold atoms in disordered potentials
• Enhancement of electron-hole superfluidity in double few-layer graphene
• Quantum critical transport in the unitary Fermi gas
• Physics of ultracold Fermi gases revealed by spectroscopies
• Phase structure of spin-imbalanced unitary Fermi gases
• Local origin of the pseudogap in the attractive Hubbard model
• Entanglement between pairing and screening in the Gorkov-Melik-Barkhudarov correction to the critical temperature throughout the BCS-BEC crossover
• Evolution of the Pseudogap in a polarized Fermi gas
• Dispersions, weights, and widths of the single-particle spectral function in the normal phase of a Fermi gas
• Pairing effects in the non-degenerate limit of the two-dimensional Fermi gas
• Pseudogap temperature and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas
• Pseudogap and preformed pairs in the imbalanced Fermi gas in two dimensions
• Uniform spin susceptibility and spin-gap phenomenon in the BCS-BEC crossover regime of an ultracold Fermi gas
• Enhanced critical temperature, pairing fluctuation effects, and BCS-BEC crossover in a two-band Fermi gas
• Thermal crossover, transition, and coexistence in Fermi polaronic spectroscopies
• Pseudogap phenomena in ultracold atomic Fermi gases
• Pairing correlations across the superfluid phase transition in the unitary Fermi gas
• Quantum phases of atomic Fermi gases with anisotropic spin-orbit coupling
• The temperature evolution of the shear viscosity in a unitary Fermi gas
• Quantitative comparison between theoretical predictions and experimental results for Bragg spectroscopy of a strongly interacting Fermi superfluid
• Flat Topological Bands and Eigenstate Criticality in a Quasiperiodic Insulator
• Ground State Properties of Spin-Orbit Coupled Bose Gases for Arbitrary Interactions
• Probing strongly interacting atomic gases with energetic atoms
• Virial expansion for a strongly correlated Fermi gas with imbalanced spin populations
• Low-dimensional pairing fluctuations and pseudogapped photoemission spectrum in a trapped two-dimensional Fermi gas
• Local observation of pair-condensation in a Fermi gas at unitarity
• High-temperature expansion for interacting fermions
• High Sensitivity RF Spectroscopy of a Strongly-Interacting Fermi Gas
• Spectral properties of one-dimensional Fermi systems after an interaction quench
• Lattice Boltzmann simulations of a two-dimensional Fermi gas at unitarity
• Comparison of strong-coupling theories for a two-dimensional Fermi gas
• Magic gap ratio for optimally robust fermionic condensation and its implications for high-Tc superconductivity
• The pseudogap regime in the unitary Fermi gas
• Specific heat and effects of pairing fluctuations in the BCS-BEC crossover regime of an ultracold Fermi gas
• Hartree shift in unitary Fermi gases
• Strain induced superconductor-insulator transition on Lieb lattice
• Pairing and the spin susceptibility of the polarized unitary Fermi gas in the normal phase
• Probing open- and closed-channel p-wave resonances
• Mesoscopic spin transport between strongly interacting Fermi gases
• Excitation properties and effects of mass imbalance in the BCS-BEC crossover regime of an ultracold Fermi gas
• Symmetry Obstruction to Fermi Liquid Behavior in the Unitary Limit
• Strong-coupling corrections to spin susceptibility in the BCS-BEC crossover regime of a superfluid Fermi gas
• BCS-BEC crossover at finite temperature in spin-orbit coupled Fermi gases
• The BCS-BEC Crossover
• Strong coupling s-wave superconductors in the extreme Pauli limit: I.The breached pair and metastable FFLO phases
• Ultra-cold Fermi gases with resonant dipole-dipole interaction
• Diagnostics of nonergodic extended states and many body localization proximity effect through real-space and Fock-space excitations
• Population imbalanced lattice fermions near the BCS-BEC crossover: II. The FFLO regime and its thermal signatures
• Population imbalanced lattice fermions near the BCS-BEC crossover: I.The breached pair and metastable FFLO phases
• Effective theory and universal relations for Fermi gases near a $d$-wave interaction resonance
• Perfect-fluid behavior of a dilute Fermi gas near unitary
• Pairing and radio-frequency spectroscopy in two-dimensional Fermi gases
• Observation of Preformed Electron-Hole Cooper Pairs
• Entanglement between two spatially separated ultracold interacting Fermi gases
• Hetero pairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with mass imbalance
• Single-particle spectral functions in the normal phase of a strongly-attractive Bose-Fermi mixture
• Hidden fermionic excitation in the superconductivity of the strongly attractive Hubbard model
• Local Photoemission Spectra and Effects of Spatial Inhomogeneity in the BCS-BEC Crossover Regime of a Trapped Ultracold Fermi Gas
• Critical region of the superfluid transition in the BCS-BEC crossover
• Thermal equation of state of polarized fermions in one dimension via complex chemical potentials
• Pair condensation in a Finite Trapped Fermi Gas
• Stability of the Superfluid State in Three-Component Fermionic Optical Lattice Systems
• Pairing and pair superfluid density in one-dimensional Hubbard models
• Momentum-resolved spectroscopy of a Fermi liquid
• Pseudogap phenomenon and effects of population imbalance in the normal state of a unitary Fermi gas
• Mechanism of screening or enhancing the pseudogap throughout the two-band Bardeen-Cooper-Schrieffer to Bose-Einstein condensate crossover
• Pair fraction in a finite temperature Fermi gas on the BEC side of the BCS-BEC crossover
• Precursor of Superfluidity in a Strongly Interacting Fermi Gas with Negative Effective Range
• Goldstino in supersymmetric Bose-Fermi mixtures in the presence of Bose Einstein condensate
• Spectroscopy of dipolar fermions in 2D pancakes and 3D lattices
• Dynamics of critical fluctuations: Theory -- phenomenology -- heavy-ion collisions
• Observation of emergent scaling of spin-charge correlations at the onset of the pseudogap
• Coexistence of superfluid gap and pseudogap in the BCS-BEC crossover regime of a trapped Fermi gas below $T_{\mathrm{c}}$
• Probing quantum many-body correlations by universal ramping dynamics
• Potassium-Doped Para-Terphenyl: Structure, Electrical Transport Properties and Possible Signatures of a Superconducting Transition
• QCD-like phase diagram with Efimov trimers and Cooper pairs in resonantly interacting SU(3) Fermi gases
• Anisotropic Superfluidity in the Two-Species Polar Fermi Gas
• Quantum probe spectroscopy for cold atomic systems
• Effects of a particle-hole asymmetric pseudogap on Bogoliubov quasiparticles
• Spin Susceptibility Above the Superfluid Onset in Ultracold Fermi Gases
• Pairing fluctuations and anisotropic pseudogap phenomenon in an ultracold superfluid Fermi gas with plural $p$-wave superfluid phases
• Formation of magnetic impurities and pair-breaking effect in a superfluid Fermi gas
• Normal mass density of a superfluid Fermi gas at unitarity
• Evolution of Cooper pairs with zero-center-of-mass momentum and their first-order correlation function in a two-dimensional ultracold Fermi gas near the observed Berezinskii-Kosterlitz-Thouless transition
• Evolution of an attractive polarized Fermi gas: From a Fermi liquid of polarons to a non-Fermi liquid at the Fulde-Ferrell-Larkin-Ovchinnikov quantum critical point
• Effect of the particle-hole channel on BCS--Bose-Einstein condensation crossover in atomic Fermi gases
• Single-particle Excitations and Strong Coupling Effects in the BCS-BEC Crossover Regime of a Rare-Earth Fermi Gas with an Orbital Feshbach Resonance
• Superfluidity of Dirac Fermions in a Tunable Honeycomb Lattice: Cooper Pairing, Collective Modes, and Critical Currents
• Landau-Khalatnikov phonon damping in strongly interacting Fermi gases
• Single-Particle properties of a strongly-interacting Bose-Fermi mixture with mass and population imbalance
• Pseudogap formation in organic superconductors
• Quasiparticle Dispersions and Lifetimes in the Normal State of the BCS-BEC Crossover
• Variational Monte Carlo Study of Spin-Gapped Normal State and BCS-BEC Crossover in Two-Dimensional Attractive Hubbard Model
• Fourth- and fifth-order virial expansion of harmonically trapped fermions at unitarity
• Momentum-resolved Raman spectroscopy of bound molecules in ultracold Fermi gas
• Strong-Coupling and Finite Temperature Effects on $p$-wave Contacts
• Pseudogap regime of a strongly interacting two-dimensional Fermi gas with and without confinement-induced effect range of interactions
• Dynamic structure factor of a strongly correlated Fermi superfluid within a density functional theory approach
• Generalized Crossover in Interacting Fermions within the Low-Energy Expansion
• In Situ Momentum Distribution Measurement of a Quantum Degenerate Fermi Gas using Raman Spectroscopy
• Thermal transitions, pseudogap behavior and BCS-BEC crossover in Fermi-Fermi mixtures
• BCS-BEC Crossover Effects and Pseudogap in Neutron Matter
• Superconductivity of the FeSe/SrTiO3 Interface in the View of BCS-BEC Crossover
• Spectral functions of the strongly interacting 3D Fermi gas
• Tuning across the BCS-BEC crossover in the multiband superconductor Fe${}_{1+y}$Se${}_x$Te${}_{1-x}$ : An angle-resolved photoemission study
• Cooling schemes for two-component fermions in layered optical lattices
• Optical spin conductivity in ultracold quantum gases
• Spin susceptibility and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas
• A Holographic Model for Pseudogap in BCS-BEC Crossover (I): Pairing Fluctuations, Double-Trace Deformation and Dynamics of Bulk Bosonic Fluid
• Spin Andreev-like reflection in metal-Mott insulator heterostructures
• Low-Dimensional Fluctuations and Pseudogap in Gaudin-Yang Fermi Gases
• On the Gravitational Wave to Matter Coupling of Superfluid Fermi Gases Near Unitarity
• Single-particle Excitations and Effects of Hetero-pairing Fluctuations in a Bose-Fermi Mixture with a Feshbach Resonance
• Band manipulation and spin texture in interacting moiré helical edges
• Virial coefficients for Bose and Fermi trapped gases beyond the unitary limit: an S-Matrix approach
• Transport of Spin and Mass at Normal-Superfluid Interfaces in the Unitary Fermi Gas
• Dimensional crossover in ultracold Fermi gases from Functional Renormalisation
• Dynamic properties of superconductors: Anderson-Bogoliubov mode and Berry phase in BCS and BEC regimes
• Spectroscopic Bogoliubov features near the unitary limit
• Viscosity Bound Violation in Viscoelastic Fermi Liquids
• Mass-imbalanced Fermi gases with spin-orbit coupling
• Stable pair liquid phase in fermionic systems
• Insulator-pseudogap crossover in the Lieb lattice
• Breaking and trapping Cooper pairs by Rydberg-molecule spectroscopy in atomic Fermi superfluids
• Dynamical effects on superconductivity in BCS-BEC crossover
• Radio-Frequency Manipulation of Fano-Feshbach Resonances in an Ultracold Fermi Gas of ${}^{40}$K
• Ground states of atomic Fermi gases in a two-dimensional optical lattice with and without population imbalance
• Dissociation of Feshbach molecules via spin-orbit coupling in ultracold Fermi gases
• Dynamics of a quantum quench in an ultra-cold atomic BCS superfluid
• Universal Signatures of Majorana-like Quasiparticles in Strongly Correlated Landau-Fermi Liquids
• Resonant scattering effect in spectroscopies of interacting atomic gases
• Fluctuation Theory of Rashba Fermi Gases
• Quantum Bose and Fermi gases with large negative scattering length in the 2-body S-matrix approximation
• Superfluid/ferromagnet/superfluid junction and $\pi$-phase in a superfluid Fermi gas
• Spin-dipole mode in a trapped Fermi gas near unitarity
• Pseudogap regime of a two-dimensional uniform Fermi gas
• Ultracold Atoms in Disordered Potentials: Elastic Scattering Time in the Strong Scattering Regime
• Pseudogap phenomena near the BKT transition of a two-dimensional ultracold Fermi gas in the crossover region
• Radio frequency spectroscopy of the attractive Hubbard model in a trap
• Many-body effects in a Bose-Fermi mixture
• Isothermal compressibility and effects of multi-body molecular interactions in a strongly interacting ultracold Fermi gas
• Rashbon bound states associated with a spherical spin-orbit coupling in an ultracold Fermi gas with an $s$-wave interaction
• Hidden Bose-Einstein Singularities in Correlated Electron Systems
• Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases
• Specific Heat and Effects of Uniaxial Anisotropy of a $p$-wave Pairing Interaction in a Strongly Interacting Ultracold Fermi Gas
• In-medium bound-state formation and inhomogeneous condensation in Fermi gases in a hard-wall box
• Hidden Pseudogap and Excitation Spectra in a Strongly Coupled Two-Band Superfluid/Superconductor
• Two-dimensional pseudogap effects of an ultracold Fermi gas in the BCS-BEC crossover region
• Thermal-assisted Anisotropy and Thermal-driven Instability in the Superfluidity state of Two-Species Polar Fermi Gas
• Defining a critical temperature of a crossover from BEC to the normal phase in anisotropic quantum magnets
• Normal-state Properties of a Unitary Bose-Fermi Mixture: A Combined Strong-coupling Approach with Universal Thermodynamics
• Superfluidity in multicomponent fermions via the functional renormalization group
• Spectral intensity distribution of trapped fermions
• Hidden Bose-Einstein Singularities in Correlated Electron Systems: II. Pseudogap Phase in the Weakly Attractive Hubbard Model
• Pairing fluctuation effects in a strongly coupled color superfluid/superconductor
• Critical pairing fluctuations in the normal state of a superconductor: pseudogap and quasi-particle damping
• Probing the homogeneous spectral function of a strongly interacting superfluid atomic Fermi gas in a trap using phase separation and momentum resolved rf spectroscopy
• Quasiparticle states driven by a scattering on the preformed electron pairs
• Spin susceptibility and effects of inhomogeneous strong pairing fluctuations in a trapped ultracold Fermi gas
• Fluctuation conductivity due to the preformed local pairs
• Inhomogeneous Pseudogap Phenomenon in the BCS-BEC Crossover Regime of a Trapped Superfluid Fermi Gas
• Theory of Photoemission-type Experiment in the BCS-BEC Crossover Regime of a Superfluid Fermi Gas
• Superconducting Dirac point in proximetized graphene
• Spin Susceptibility and Strong Coupling Effects in an Ultracold Fermi Gas
• Fluctuation-induced first-order superfluid transition in unitary $\mathrm{SU}(N)$ Fermi gases
• Interplay of the pseudogap and the BCS gap for heteropairs in ${}^{40}$K-${}^6$Li mixture
• Equivalence of dissipative and dissipationless dynamics of interacting quantum systems with its application to the unitary Fermi gas
• Metastability of Bose and Fermi gases on the upper branch
• Spectral weight suppression in response functions of ultracold fermion-boson mixtures