Momentum distribution and the universal contact of a unitary Fermi gas with particle-hole fluctuation

We compute the momentum distribution of a homogeneous Fermi gas at unitarity in the normal phase within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. From the large-momentum behavior of momentum distribution, we obtain the contact for the unitary Fermi gas. We also compare our results with experimental data and other theoretical predictions.

Download Full-text

The energy of a unitary Fermi gas in the normal phase including the effect of induced interaction

Modern Physics Letters B ◽

10.1142/s0217984915502073 ◽

2015 ◽

Vol 29 (32) ◽

pp. 1550207 ◽

Cited By ~ 2

Author(s):

Hao Gong ◽

Xiao-Xia Ruan ◽

Hou-Rong Pang ◽

Hong-Shi Zong

Keyword(s):

Experimental Data ◽

Chemical Potential ◽

Normal Phase ◽

Fermi Gases ◽

Matrix Approximation ◽

Ultracold Fermi Gases ◽

Self Consistent ◽

Unitary Fermi Gas ◽

T Matrix ◽

Good Agreement

In this paper, taking into account the effect of the induced interaction, we calculate the energy of ultracold Fermi gases at unitarity in the framework of non-self-consistent T-matrix approximation (nTMA) above the critical temperature and compare the result with the experimental data and other theoretical calculation without induced interaction. Our calculated chemical potential is higher than the experimental data, but our calculated energy obtains a good agreement with Tokyo experiment for temperature range between [Formula: see text] and [Formula: see text].

Download Full-text

The pressure and entropy of a unitary Fermi gas with particle-hole fluctuation

Modern Physics Letters B ◽

10.1142/s021798491750364x ◽

2018 ◽

Vol 32 (01) ◽

pp. 1750364

Author(s):

Hao Gong ◽

Xiao-Xia Ruan ◽

Hong-Shi Zong

Keyword(s):

Experimental Data ◽

Fermi Gas ◽

Experimental Measurements ◽

Matrix Approximation ◽

Self Consistent ◽

Unitary Fermi Gas ◽

T Matrix ◽

Theoretical Results ◽

Previous Prediction ◽

Good Agreement

We calculate the pressure and entropy of a unitary Fermi gas based on universal relations combined with our previous prediction of energy which was calculated within the framework of the non-self-consistent T-matrix approximation with particle-hole fluctuation. The resulting entropy and pressure are compared with the experimental data and the theoretical results without induced interaction. For entropy, we find good agreement between our results with particle-hole fluctuation and the experimental measurements reported by ENS group and MIT experiment. For pressure, our results suffer from a systematic upshift compared to MIT data.

Download Full-text

High-frequency tail of the radio-frequency spectrum in a unitary Fermi gas with particle–hole fluctuation

Modern Physics Letters B ◽

10.1142/s0217984918502809 ◽

2018 ◽

Vol 32 (24) ◽

pp. 1850280

Author(s):

Xiao-Xia Ruan ◽

Fei Wang ◽

Hao Gong ◽

Zheng-Ling Wang ◽

Hong-Shi Zong

Keyword(s):

Radio Frequency ◽

Frequency Spectrum ◽

High Frequency ◽

Ultracold Atoms ◽

Fermi Gas ◽

Normal Phase ◽

Matrix Approximation ◽

Self Consistent ◽

Radio Frequency Spectrum ◽

Unitary Fermi Gas

The contact plays an important role in the study of ultracold atoms. We determine the contact from the high-frequency asymptotic behavior of radio-frequency spectrum for a homogeneous Fermi gas at unitarity in the normal phase. The contact is obtained within the framework of the non-self-consistent T-matrix approximation with particle–hole fluctuation.

Download Full-text

MOMENTUM RESOLVED RADIO FREQUENCY SPECTROSCOPY OF A UNITARY FERMI GAS WITH EXTENDED GMB APPROXIMATION

Modern Physics Letters B ◽

10.1142/s0217984914500286 ◽

2014 ◽

Vol 28 (04) ◽

pp. 1450028 ◽

Cited By ~ 1

Author(s):

XIAO-XIA RUAN ◽

HAO GONG ◽

LONG DU ◽

YU JIANG ◽

WEI-MIN SUN ◽

...

Keyword(s):

Radio Frequency ◽

High Temperature Superconductivity ◽

Fermi Gas ◽

Normal Phase ◽

Matrix Approximation ◽

Frequency Spectra ◽

Self Consistent ◽

Unitary Fermi Gas ◽

Different Temperatures ◽

Radio Frequency Spectroscopy

In this paper, the momentum-resolved radio-frequency spectra of a unitary Fermi gas in the normal phase are presented and analyzed on the basis of the framework of the non-self-consistent T-matrix approximation with the extended Gorkov and Melik-Barkhudarov (GMB) approximation. We report the calculated occupied spectral intensity and energy distribution curves for different temperatures above T c . Our results indicate the existence of pseudogap phenomenon which would be helpful for further understanding of the pseudogap in high-temperature superconductivity.

Download Full-text

SELF-CONSISTENT T-MATRIX APPROXIMATION TO THE HUBBARD MODEL FOR A FINITE NUMBER OF SITES

Modern Physics Letters B ◽

10.1142/s0217984909020205 ◽

2009 ◽

Vol 23 (16) ◽

pp. 2049-2062

Author(s):

MOHSEN JEMAÏ

Keyword(s):

Finite Number ◽

Hubbard Model ◽

Random Phase Approximation ◽

Random Phase ◽

Fermi Gas ◽

Phase Approximation ◽

Matrix Approximation ◽

Numerical Effort ◽

Self Consistent ◽

T Matrix

Within the 1D Hubbard model, linear closed chains with various numbers of sites are considered in particle–particle self-consistent random phase approximation (SCRPA) for the T-matrix. Encouraging results with a minimal numerical effort are obtained, confirming earlier results with this theory for other models. SCRPA solves the two-site problem exactly. It therefore contains the two electrons and high density Fermi gas limits correctly.

Download Full-text

SPECTRAL FUNCTION AND DOS OF ULTRACOLD FERMI GASES IN THE NORMAL PHASE INCLUDING THE EFFECT OF INDUCED INTERACTION

Modern Physics Letters B ◽

10.1142/s021798491350214x ◽

2013 ◽

Vol 27 (29) ◽

pp. 1350214 ◽

Cited By ~ 3

Author(s):

HAO GONG ◽

XIAO-XIA RUAN ◽

LONG DU ◽

WEI-MIN SUN ◽

HONG-SHI ZONG

Keyword(s):

Spectral Function ◽

High Accuracy ◽

Normal Phase ◽

Fermi Gases ◽

Matrix Approximation ◽

Real Frequency ◽

Ultracold Fermi Gases ◽

Self Consistent ◽

T Matrix ◽

Frequency Axis

In this paper, taking into account the effect of the induced interaction, we calculate the spectral function and hence density of states (DOS) of ultracold Fermi gases within the framework of non-self-consistent T-matrix approximation (nTMA) in the normal phase. The corresponding equations are calculated on the real-frequency axis directly with high accuracy. Our result shows that pseudogap phenomenon still exists in the spectral function and DOS.

Download Full-text