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Register a new userGeneral Quasiparticle Propagator and Mass Dependence in Degenerate Color Superconductivity
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Todd. D. Fugleberg
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The general quasiparticle propagator in dense quark matter is derived for equal mass quarks. Specialized to an NJL model, this propagator includes one new condensate, $Delta_3$, in addition to the usual CFL condensate, $Delta_1$. The gap equation is solved in two NJL models and the dependence on the quark mass of the condensates and the gap is presented. Analytic approximations for the condensates are obtained and compared to exact numerical solutions. The results are shown to differ from those obtained by neglecting $Delta_3$, especially for smaller values of $Delta_1$. The two different NJL models presented are also shown to give different results when $Delta_3$ is not neglected. The methods used in this paper can be generalized to the physical case where only the strange quark is significantly massive.
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In dense quark matter, the response of the color superconducting gaps to a small variation, $deltamu$, in the chemical potential of the strange quark was studied. The approximation of three massless flavors of quarks and a general ansatz for the color flavor structure of the gap matrix was used. The general pole structure of the quasi-particle propagator in this ansatz is presented. The gap equation was solved using both an NJL interaction model and perturbative single gluon exchange at moderate densities and results are presented for varying values of $deltamu$. Quantitative and qualitative differences in the dependence of the gaps on $deltamu$ were found.
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One of the most important mathematical tools necessary for Quantum Field Theory calculations is the field propagator. Applications are always done in terms of plane waves and although this has furnished many magnificent results, one may still be allowed to wonder what is the form of the most general propagator that can be written. In the present paper, by exploiting what is called polar form, we find the most general propagator in the case of spinors, whether regular or singular, and we give a general discussion in the case of vectors.
We study a model for color superconductivity with both three colors and massless flavors including quark pairing. By using the Hamiltonian in the color-flavor basis we can calculate the quantum entropy. From this we are able to further investigate the phases of the color superconductor, for which we find a rather sharp transition to color superconductivity above a chemical potential around $290 $MeV.
Based on transversality condition of gauge boson self-energy we have systematically constructed the general structure of the gauge boson two-point functions using four linearly independent basis tensors in presence of a nontrivial background, i.e., hot magnetized material medium. The hard thermal loop approximation has been used for the heat bath to compute various form factors associated with the gauge bosons two point functions both in strong and weak field approximation. We have also analyzed the dispersion of a gauge boson (e.g., gluon) using the effective propagator both in strong and weak magnetic field approximation. The formalism is also applicable to QED. The presence of only thermal background leads to a longitudinal (plasmon) mode and a two-fold degenerate transverse mode. In presence of a hot magnetized background medium the degeneracy of the two transverse modes is lifted and one gets three quasiparticle modes. In weak field approximation one gets two transverse modes and one plasmon mode. On the other hand, in strong field approximation also one gets the three modes in Lowest Landau Level. The general structure of two-point function may be useful for computing the thermo-magnetic correction of various quantities associated with a gauge boson.
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