Fermi gas throughout the BCS-BEC crossover: Comparative study of t-matrix approaches with various degrees of self-consistency
arXiv:1903.01960 · doi:10.1103/PhysRevB.99.094502
Abstract
The diagrammatic t-matrix approximation has often been adopted to describe a dilute Fermi gas. This approximation, originally considered by Galitskii for a repulsive inter-particle interaction (Galitskii-1958), has later been widely utilized for an attractive Fermi gas to describe the BCS-BEC crossover from strongly overlapping Cooper pairs in weak coupling to non-overlapping composite bosons in strong coupling. Several variants of the -matrix approximation have been considered in the literature, which are distinguished by the degree of self-consistency allowed in the building blocks of the diagrammatic structure. Here, we perform a systematic and comparative study of all possible variants on the degree of self-consistency for the -matrix approximation in an attractive Fermi gas, which enables us to confront their outcomes for thermodynamic and dynamical quantities on the same footing in an unbiased way. For definiteness, only the normal phase above the superfluid critical temperature is considered. The dispute that can be raised in this context, about the adequateness of introducing progressive degrees of self-consistency over and above the non-self-consistent -matrix approximation for an attractive Fermi gas, parallels the recent interest in the literature on assessing the importance of various degrees of self-consistency in the context of semiconductors and insulators.
arXiv comment20 pages, 13 figures
References in corpus (31)
- BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
- Large momentum part of fermions with large scattering length
- Energetics of a strongly correlated Fermi gas
- Generalized Virial Theorem and Pressure Relation for a strongly correlated Fermi gas
- Thermodynamics of the BCS-BEC crossover
- The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
- Pseudogap and spectral function from superconducting fluctuations to the bosonic limit
- A Benchmark of GW Methods for Azabenzenes: Is the GW Approximation Good Enough?
- On the correct strong-coupling limit in the evolution from BCS superconductivity to Bose-Einstein condensation
- Quantum Monte Carlo Simulations of the BCS-BEC Crossover at Finite Temperature
- Pseudogap effects induced by resonant pair scattering
- Non-existence of the Luttinger-Ward functional and misleading convergence of skeleton diagrammatic series for Hubbard-like models
- A reliable Pade analytical continuation method based on a high accuracy symbolic computation algorithm
- Evolution of the Normal State of a Strongly Interacting Fermi Gas from a Pseudogap Phase to a Molecular Bose Gas
- Fermi-Liquid Behavior of the Normal Phase of a Strongly Interacting Gas of Cold Atoms
- Critical Temperature Curve in the BEC-BCS Crossover
- Beyond the quasiparticle approximation: Fully self-consistent calculations
- Analytic continuation by averaging Padé approximants
- Enhanced paraconductivity-like fluctuations in the radio frequency spectra of ultracold Fermi atoms
- Comparative study of strong coupling theories of a trapped Fermi gas at unitarity
- Spin susceptibility and fluctuation corrections in the BCS-BEC crossover regime of an ultracold Fermi gas
- Pairing effects in the normal phase of a two-dimensional Fermi gas
- Superfluid Fermi atomic gas as a quantum simulator for the study of neutron-star equation of state
- Green functions and self-consistency: insights from the spherium model
- Vertex corrections to the polarizability do not improve the GW approximation for the ionization potential of molecules
- Comparison of Different Pairing Fluctuation Approaches to BCS-BEC Crossover
- The Equation of State of the Unitary Fermi Gas: An Update on Lattice Calculations
- Entanglement between pairing and screening in the Gorkov-Melik-Barkhudarov correction to the critical temperature throughout the BCS-BEC crossover
- Gap equation with pairing correlations beyond mean field and its equivalence to a Hugenholtz-Pines condition for fermion pairs
- Dynamical correlations in multiorbital Hubbard models: Fluctuation-exchange approximations
- Diagrammatic Monte Carlo algorithm for the resonant Fermi gas
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- When Superconductivity Crosses Over: From BCS to BEC
- Polaron Problems in Ultracold Atoms: Role of a Fermi Sea across Different Spatial Dimensions and Quantum Fluctuations of a Bose Medium
- Thermal crossover, transition, and coexistence in Fermi polaronic spectroscopies
- Pairing correlations across the superfluid phase transition in the unitary Fermi gas
- Pairing and the spin susceptibility of the polarized unitary Fermi gas in the normal phase
- Beyond-mean-field description of a trapped unitary Fermi gas with mass and population imbalance
- BCS-BEC Crossover and Pairing Fluctuations in a Two Band Superfluid/Superconductor: A T Matrix Approach
- Pair fraction in a finite temperature Fermi gas on the BEC side of the BCS-BEC crossover
- Anomalous propagators and the particle-particle channel: Hedin's equations
- Mechanism of screening or enhancing the pseudogap throughout the two-band Bardeen-Cooper-Schrieffer to Bose-Einstein condensate crossover
- Pair correlations in the normal phase of an attractive Fermi gas
- Three-dimensional electron-hole superfluidity in a superlattice close to room temperature
- 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
- Thermodynamic stability, compressibility matrix, and effects of mediated interactions in a strongly-interacting Bose-Fermi mixture
- Pairing patterns in polarized unitary Fermi gases above the superfluid transition
- Beyond mean-field corrections to the quasiparticle spectrum of superfluid Fermi gases
- Spectral functions of the strongly interacting 3D Fermi gas
- Spatial emergence of Off-Diagonal Long-Range Order throughout the BCS-BEC crossover
- Low-momentum interactions for ultracold Fermi gases
- Detecting the phase transition in a strongly-interacting Fermi gas by unsupervised machine learning
- Particle and pair spectra for strongly correlated Fermi gases: A real-frequency solver
- Spectral properties and observables in ultracold Fermi gases
- Isothermal compressibility and effects of multi-body molecular interactions in a strongly interacting ultracold Fermi gas
- Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases
- Mutual friction and vortex Hall angle in a strongly interacting Fermi superfluid
- The Gor'kov and Melik-Barkhudarov correction to an imbalanced Fermi gas in the presence of impurities
- The normal state of attractive Fermi gases from coupled-cluster theory
- Rabi coupled fermions in the BCS-BEC crossover
- A lattice pairing-field approach to ultracold Fermi gases
- Tunneling spectra of unconventional quasi-two-dimensional superconductors
- Quasiparticle disintegration in fermionic superfluids
- Non-thermal pairing glue of electrons in the steady state
- Strong Fulde-Ferrell Larkin-Ovchinnikov pairing fluctuations in polarized Fermi systems