We study the properties of a phase slip in a superfluid Fermi gas near a Feshbach resonance. The phase slip can be generated by the phase imprinting method. Below the superfluid transition temperature, it appears as a dip in the density profile and becomes more pronounced when the temperature is lowered. Therefore the phase slip can provide direct evidence of the superfluid state. The condensation energy of the superfluid state can be extracted from the density profile of the phase slip, due to the unitary properties of the Fermi gas near the resonance. The width of the phase slip is inversely proportional to the square root of the difference between the transition temperature and the temperature. The signature of the phase slip in the density profile becomes more robust across the BCS-Bose-Einstein-condensate crossover.We study the properties of a phase slip in a superfluid Fermi gas near a Feshbach resonance. The phase slip can be generated by the phase imprinting method. Below the superfluid transition temperature, it appears as a dip in the density profile and becomes more pronounced when the temperature is lowered. Therefore the phase slip can provide direct evidence of the superfluid state. The condensation energy of the superfluid state can be extracted from the density profile of the phase slip, due to the unitary properties of the Fermi gas near the resonance. The width of the phase slip is inversely proportional to the square root of the difference between the transition temperature and the temperature. The signature of the phase slip in the density profile becomes more robust across the BCS-Bose-Einstein-condensate crossover.

arXiv:cond-mat/0406542Physical Review AApr 13, 20054 citations

Fermi gas

K. Yamada

Cambridge University Press eBooksSep 23, 20040 citations

Density profile of a superfluid Fermi gas with a phase slip

Hong-Yu Wu, Yin Lan, 北京大学物理学院，北京 100871

BEC(Bose Einstein Condensation)-BCS(Bardeen Schrieffer Cooper) crossover is currently one of the main research focuses in the area of cold atoms and BEC. In this paper, we study in detail the phenomenon of a phase slip in a superfluid Fermi gas near a Feshbach resonance, based on our previous work. The density profiles of a superfluid Fermi gas with a phase slip at various temperatures are computed by numerical method. Our results show that the phase-slip phenomenon can provide a direct experimental evidence of the superfluid phase.BEC(Bose Einstein Condensation)-BCS(Bardeen Schrieffer Cooper) crossover is currently one of the main research focuses in the area of cold atoms and BEC. In this paper, we study in detail the phenomenon of a phase slip in a superfluid Fermi gas near a Feshbach resonance, based on our previous work. The density profiles of a superfluid Fermi gas with a phase slip at various temperatures are computed by numerical method. Our results show that the phase-slip phenomenon can provide a direct experimental evidence of the superfluid phase.

Acta Physica SinicaJan 1, 20065 citations

Relativistic Barnett effect and Curie law in a rigidly rotating free Fermi gas

M. Abedlou Ahadi, Néda Sadooghi A

By combining methods from thermal field theory and statistical mechanics, we reexamine the spin polarization caused by the relativistic Barnett effect in a rigidly rotating Fermi gas. We determine the pressure of this medium and show that it depends on an effective chemical potential, which includes contributions from orbital angular momentum-rotation and spin-rotation coupling. We introduce a specific regularization scheme to sum over the angular momentum quantum numbers. As a result, the thermal pressure and all thermodynamic quantities are separated into two parts that differ only in the spin fugacities of spin-up and spin-down fermions. We calculate the Fermi energy for both components and show that the Fermi energy of the spin-down fermions is lower than that of the spin-up ones. This difference arises from the spin-rotation coupling and leads to a spin polarization consistent with the Barnett effect. In particular, we introduce the spin-chemicorotational ratio $η\equiv Ω^{(0)}/2μ^{(0)}$ , which adjusts the spin polarization of the Fermi gas. Here, $Ω^{(0)}$ and $μ^{(0)}$ represent the angular velocity and chemical potential at zero temperature, respectively. The factor $1/2$ accounts for the fermion's spin. We explore the temperature dependence of $μ$ and $Ω$ , while assuming that the number of spin-up and spin-down fermions remains temperature independent. Our findings indicate that the spin-down component of the rotating Fermi gas dilutes at lower temperatures compared to the spin-up component. Additionally, we calculate the magnetic susceptibility arising from the Barnett magnetization and demonstrate that it is proportional to the moment of inertia $I$ of the rotating Fermi gas. Finally, we prove that $I$ exhibits a $1/T$ behavior in the high-temperature limit, similar to the Curie law of paramagnetism.By combining methods from thermal field theory and statistical mechanics, we reexamine the spin polarization caused by the relativistic Barnett effect in a rigidly rotating Fermi gas. We determine the pressure of this medium and show that it depends on an effective chemical potential, which includes contributions from orbital angular momentum-rotation and spin-rotation coupling. We introduce a specific regularization scheme to sum over the angular momentum quantum numbers. As a result, the thermal pressure and all thermodynamic quantities are separated into two parts that differ only in the spin fugacities of spin-up and spin-down fermions. We calculate the Fermi energy for both components and show that the Fermi energy of the spin-down fermions is lower than that of the spin-up ones. This difference arises from the spin-rotation coupling and leads to a spin polarization consistent with the Barnett effect. In particular, we introduce the spin-chemicorotational ratio $η\equiv Ω^{(0)}/2μ^{(0)}$, which adjusts the spin polarization of the Fermi gas. Here, $Ω^{(0)}$ and $μ^{(0)}$ represent the angular velocity and chemical potential at zero temperature, respectively. The factor $1/2$ accounts for the fermion's spin. We explore the temperature dependence of $μ$ and $Ω$, while assuming that the number of spin-up and spin-down fermions remains temperature independent. Our findings indicate that the spin-down component of the rotating Fermi gas dilutes at lower temperatures compared to the spin-up component. Additionally, we calculate the magnetic susceptibility arising from the Barnett magnetization and demonstrate that it is proportional to the moment of inertia $I$ of the rotating Fermi gas. Finally, we prove that $I$ exhibits a $1/T$ behavior in the high-temperature limit, similar to the Curie law of paramagnetism.

arXiv:2604.06248Apr 6, 20260 citations

The unitary Fermi gas

Joaquín E. Drut

Jan 1, 20081 citation

η\equiv Ω^{(0)}/2μ^{(0)}

, which adjusts the spin polarization of the Fermi gas. Here,

Ω^{(0)}

and

μ^{(0)}

represent the angular velocity and chemical potential at zero temperature, respectively. The factor

1/2

accounts for the fermion's spin. We explore the temperature dependence of

μ

and

Ω

, while assuming that the number of spin-up and spin-down fermions remains temperature independent. Our findings indicate that the spin-down component of the rotating Fermi gas dilutes at lower temperatures compared to the spin-up component. Additionally, we calculate the magnetic susceptibility arising from the Barnett magnetization and demonstrate that it is proportional to the moment of inertia

I

of the rotating Fermi gas. Finally, we prove that

I

exhibits a

1/T

behavior in the high-temperature limit, similar to the Curie law of paramagnetism.