Screening effects in superfluid nuclear and neutron matter within Brueckner theory

Abstract

Effects of medium polarization are studied for 1 S0 pairing in neutron and nuclear matter. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The selfenergy corrections are consistently included resulting in a strong depletion of the Fermi surface. All medium effects are calculated based on the Brueckner theory. The 1 S0 gap is determined from the generalized gap equation. The selfenergy corrections always lead to a quenching of the gap, which is enhanced by the screening effect of the pairing potential in neutron matter, whereas it is almost completely compensated by the antiscreening effect in nuclear matter.

Superfluid properties of the inner crust of neutron stars

“…Recently, ab initio quantum Monte Carlo calculations have been carried out for low-density infinite neutron matter (k F,n 0.5 fm −1 ) [48], with an effort to understand the differences with other Monte Carlo results [49][50][51]. A quenching of the mean-field pairing gap is predicted, resulting in a larger pairing gap than what previous calculations found [52][53][54][55][56].…”

Superfluid properties of the inner crust of neutron stars. II. Wigner-Seitz cells at finite temperature

“…Such kind of calculations are still not available for WS cells, mainly because of the computational time requested. According to our findings, a possible alternative could be represented by performing calculations in the infinite systems of both collective excitations [45][46][47] and pairing gaps [48]. Such results could be then used to fit an effective zero range pairing interactions.…”

Finite-size effects and collective vibrations in the inner crust of neutron stars

“…It is well known, however, that many-body effects can significantly modify the HFB results. Several studies have found that the pairing gap in neutron matter is quenched by spin fluctuations [11][12][13][14], but results obtained in uniform matter cannot be directly extrapolated to the actual case of the inhomogeneous inner crust. In fact, many-body effects in (isolated) atomic nuclei are strongly dominated by the coupling between single-particle and collective surfacelike degrees of freedom.…”