Speaker
Dr
Xinle Shang
(neutron-proton pairing)
Description
In asymmetric nuclear matter, the mismatched Fermi surfaces of neutrons and protons prevent pairing between the two species near the average Fermi surface. We propose an axi-symmetric angle-dependent gap (ADG) state with broken rotational symmetry in reference [1] by considering the angle dependence of the pairing gap in 3SD1 channel, in which the pairing gap is angle-dependent due to the noncentral 3SD1 channel pairing force. We find the angle dependence of the pairing gap can reduce the suppression of the gap by the mismatched Fermi surfaces, especially at high densities and low temperatures. When consider the FFLO state [2,3] with ADG, the superfluid state is nondegenerate for the orientations of the Cooper pair momentum. There are two kinds of locally stable orientations, which correspond to the pair momentum orthogonal and parallel to the symmetry axis of the ADG (the FFLO–ADG–orthogonal state and FFLO–ADG–parallel state) [4], respectively. The FFLO–ADG–orthogonal state is located at small asymmetry, whereas the FFLO–ADG–parallel state is favored for large asymmetry.
[1] X-L Shang, and W Zuo, Phys. Rev. C 88 025806 (2013)
[2] P. Fulde, and R. A. Ferrell, Phys. Rev. 135, A550 (1964).
[3] A. I. Larkin, and Y. N. Ovchinnikov, Zh. Eksp. Teor. Fiz. 47, 1136 (1964) [Sov. Phys. JETP 20, 762 (1965)].
[4] Xinle Shang, Pei Wang, Peng Yin and Wei Zuo, J. Phys. G: Nucl. Part. Phys. 42 (2015) 055105
Author
Dr
Xinle Shang
(neutron-proton pairing)
Co-author
Prof.
Wei ZUO
(Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China)
