The pseudogap regime in the unitary Fermi gas

Jensen, Scott; Gilbreth, C. N.; Alhassid, Y.

doi:10.1140/epjst/e2019-800105-y

Cited by 27 publications

(26 citation statements)

References 132 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A pseudogap phenomenon, which is the suppression of the density of states (DOS) around a Fermi level, has been a central issue in strongly correlated quantum many-body systems such as high-T c superconductors [1][2][3][4][5], ultracold atoms [6][7][8][9][10][11][12][13][14], and nuclear and quark matter [15][16][17][18][19][20]. Although the origin of the pseudogap strongly depends on the properties of each system, it is believed that the pseudogap is induced by fluctuation effects dominating nontrivial characters of the systems.…”

Section: Introductionmentioning

confidence: 99%

Low-dimensional fluctuations and pseudogap in Gaudin-Yang Fermi gases

Tajima

Tsutsui

Doi

2020

Phys. Rev. Research

View full text Add to dashboard Cite

The pseudogap is a ubiquitous phenomenon in strongly correlated systems, such as high-T c superconductors, ultracold atoms, and nuclear physics. Whereas pairing fluctuations inducing the pseudogap are known to be enhanced in low-dimensional systems, such effects have not been explored well in one of the most fundamental one-dimensional models, that is, Gaudin-Yang model. In this paper, we show how the pseudogap effect emerges in the single-particle excitation in this system using a diagrammatic approach. Fermionic single-particle spectra exhibit a unique crossover from the double-particle dispersion to the pseudogap state with increasing the attractive interaction and the number density at finite temperature. Surprisingly, our results of thermodynamic quantities in unpolarized and polarized gases show an excellent agreement with the recent quantum Monte Carlo and complex Langevin results, indicating the validity of our approach even in the region where the pseudogap appears.

show abstract

Section: Introductionmentioning

confidence: 99%

Low-dimensional fluctuations and pseudogap in Gaudin-Yang Fermi gases

Tajima

Tsutsui

Doi

2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…In strongly interacting systems, such as neutron matter and the unitary Fermi gas, effects of pairing fluctuations near the superfluid phase transition are particularly important. Such effects have extensively been studied in cold Fermi gas physics through the observations of various quantities, such as the single-particle excitation spectrum, specific heat, superfluid phase transition temperature ( T c ), shear viscosity, and spin susceptibility 10,12,13 . Three of the present authors have recently shown 14 that a strong coupling theory, being based on the one developed by Nozières and Schmitt-Rink (NSR) 15 can provide a unified description of neutron matter and an ultracold Fermi gas in the unitary regime.…”

Section: Introductionmentioning

confidence: 99%

Superfluid Phase Transitions and Effects of Thermal Pairing Fluctuations in Asymmetric Nuclear Matter

Tajima

Hatsuda

Wyk

et al. 2019

Sci Rep

View full text Add to dashboard Cite

We investigate superfluid phase transitions of asymmetric nuclear matter at finite temperature (T) and density (ρ) with a low proton fraction (Yp ≤ 0.2), which is relevant to the inner crust and outer core of neutron stars. A strong-coupling theory developed for two-component atomic Fermi gases is generalized to the four-component case, and is applied to the system of spin-1/2 neutrons and protons. The phase shifts of neutron-neutron (nn), proton-proton (pp) and neutron-proton (np) interactions up to k = 2 fm−1 are described by multi-rank separable potentials. We show that the critical temperature of the neutron superfluidity at Yp = 0 agrees well with Monte Carlo data at low densities and takes a maximum value = 1.68 MeV at with ρ0 = 0.17 fm−3. Also, the critical temperature of the proton superconductivity for Yp ≤ 0.2 is substantially suppressed at low densities due to np-pairing fluctuations, and starts to dominate over only above (0.77) for Yp = 0.1(0.2), and (iii) the deuteron condensation temperature is suppressed at Yp ≤ 0.2 due to a large mismatch of the two Fermi surfaces.

show abstract

“…Here we use an improved finite-temperature auxiliaryfield quantum Monte Carlo (AFMC) [43] method on a spatial lattice to calculate the temperature dependence of the contact across the superfluid transition for 40, 66, and 114 particles. Our AFMC method works in the canonical ensemble and uses an algorithm we recently introduced [44][45][46] that enables calculations for much larger lattices than would otherwise be feasible. For each of these particle numbers, we extrapolate to the continuum limit, eliminating systematic errors due to a finite filling factor (or equivalently finite effective range r e [47]).…”

mentioning

confidence: 99%

Contact in the Unitary Fermi Gas across the Superfluid Phase Transition

2020

Self Cite

View full text Add to dashboard Cite

A quantity known as the contact is a fundamental thermodynamic property of quantum many-body systems with short-range interactions. Determination of the temperature dependence of the contact for the unitary Fermi gas of infinite scattering length has been a major challenge, with different calculations yielding qualitatively different results. Here we use finite-temperature auxiliary-field quantum Monte Carlo (AFMC) methods on the lattice within the canonical ensemble to calculate the temperature dependence of the contact for the homogeneous spin-balanced unitary Fermi gas. We extrapolate to the continuum limit for 40, 66, and 114 particles, eliminating systematic errors due to finite-range effects. We observe a dramatic decrease in the contact as the superfluid critical temperature is approached from below, followed by a gradual weak decrease as the temperature increases in the normal phase. Our theoretical results are in excellent agreement with the most recent precision ultracold atomic gas experiments. We also present results for the energy as a function of temperature in the continuum limit.

show abstract

The pseudogap regime in the unitary Fermi gas

Cited by 27 publications

References 132 publications

Low-dimensional fluctuations and pseudogap in Gaudin-Yang Fermi gases

Low-dimensional fluctuations and pseudogap in Gaudin-Yang Fermi gases

Superfluid Phase Transitions and Effects of Thermal Pairing Fluctuations in Asymmetric Nuclear Matter

Contact in the Unitary Fermi Gas across the Superfluid Phase Transition

Contact Info

Product

Resources

About