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Starting from the linearized BdG-equation we make the simple observation that pairing can occur between particles with total momenta different from zero, e.g., with equal momentum and opposite spin, in cases of an effective interaction…

Superconductivity · Physics 2022-08-25 C. Hainzl , M. Loss

Pairing correlations have a strong influence on nuclear level densities. Empirical descriptions and theoretical models have been developed to take these effects into account. The present article discusses cases, where descriptions of…

Nuclear Theory · Physics 2015-06-11 Karl-Heinz Schmidt , Beatriz Jurado

Low-lying nuclear states of Sm isotopes are studied in the framework of a collective Hamiltonian based on covariant energy density functional theory. Pairing correlation are treated by both BCS and Bogoliubov methods. It is found that the…

Nuclear Theory · Physics 2015-06-18 J. Xiang , Z. P. Li , J. M. Yao , W. H. Long , P. Ring , J. Meng

A brief review of recent progress in the ab intio theory of nuclear pairing is given. Nowdays several successful solutions of the ab intio BCS theory gap equation were published which show that it is a promising first step in the problem.…

Nuclear Theory · Physics 2017-08-23 Eduard E. Saperstein , Marcello Baldo

We discuss various properties of singlet S pairing in neutron and nuclear matter in terms of the bare nuclon-nucleon interaction. Relations to the NN phase shifts are discussed, as well as various properties of the BCS wave function and the…

Nuclear Theory · Physics 2007-05-23 O. Elgaroy , M. Hjorth-Jensen

Using the Bethe-Salpeter (BS) equation, Cooper pairing can be generalized to include contributions from holes as well as particles from the ground state of either an ideal Fermi gas (IFG) or of a BCS many-fermion state. The BCS model…

Superconductivity · Physics 2009-11-07 M. Fortes , M. A. Solis , M. de Llano , V. V. Tolmachev

We report on recent progress in understanding pairing phenomena in low-density nuclear matter at small and moderate isospin asymmetry. A rich phase diagram has been found comprising various superfluid phases that include a homogeneous and…

Nuclear Theory · Physics 2014-04-04 Martin Stein , Armen Sedrakian , Xu-Guang Huang , John W. Clark , Gerd Röpke

A theoretical methodology for exploring the conventional Bardeen-Cooper-Schrieffer (BCS) pairing instability for superconductivity from a correlated normal phase for all possible degrees of many-body correlation, has been developed. The…

Superconductivity · Physics 2021-02-24 Koushik Mandal , Ranjan Chaudhury

Cooper pairing in two dimensions is analyzed with a set of renormalized equations to determine its binding energy for any fermion number density and all coupling assuming a generic pairwise residual interfermion interaction. \ Also…

Superconductivity · Physics 2016-08-15 S. K. Adhikari , M. Casas , A. Puente , A. Rigo , M. Fortes , M. A. Solís , M. de Llano , A. A. Valladares , O. Rojo

We propose a field-theoretical approach to a polymer system immersed in an ideal mixture of clustering centers. The system contains several species of these clustering centers with different functionality, each of which connects a fixed…

Materials Science · Physics 2015-05-28 Riccardo Fantoni , Kristian K. Muller-Nedebock

We consider inter- and intra-species pairing interactions in an asymmetrical Fermi system. Using equation of motion method, we obtain coupled mean-field equations for superfluid gap functions and population densities. We construct a phase…

Superconductivity · Physics 2014-04-24 Renyuan Liao , Khandker F. Quader

Motivated by recent proposals of correlation induced insensitivity of d-wave superconductors to impurities, we develop a simple pairing theory for these systems for up to a moderate strength of disorder. Our description implements the key…

Superconductivity · Physics 2017-11-01 Debmalya Chakraborty , Nitin Kaushal , Amit Ghosal

Fermi gas with time-dependent pairing interaction hosts several different dynamical states. Coupling between the collective BCS pairing mode and individual Cooper pair states can make the latter either synchronize or dephase. We describe…

Mesoscale and Nanoscale Physics · Physics 2008-04-12 R. A. Barankov , L. S. Levitov

We provide a novel mechanism that resolves the Big Bang Singularity present in FRW space-times without the need for ghost fields. Building on the fact that a four-fermion interaction arises in General Relativity when fermions are…

High Energy Physics - Theory · Physics 2009-09-02 Stephon Alexander , Tirthabir Biswas

We show that the long-distance behavior of the two-body density correlation functions and the Cooper-pair probability density of a balanced mixture of a two-component Fermi gas at $T = 0$, is universal along the BEC-BCS crossover. Our…

The quartet condensation model (QCM) is extended for the treatment of isovector and isoscalar pairing in odd-odd N=Z nuclei. In the extended QCM approach the lowest states of isospin T=1 and T=0 in odd-odd nuclei are described variationally…

Nuclear Theory · Physics 2017-03-03 D. Negrea , N. Sandulescu , D. Gambacurta

A microscopic theory for nuclear pairing is proposed through the generalized density matrix formalism. The analytical equations are as simple as that of the BCS theory, and could be solved within a similar computer time. The current theory…

Nuclear Theory · Physics 2015-06-15 L. Y. Jia

It is an open question whether the fractional parts of nonlinear polynomials at integers have the same fine-scale statistics as a Poisson point process. Most results towards an affirmative answer have so far been restricted to almost sure…

Number Theory · Mathematics 2019-02-20 Jens Marklof , Nadav Yesha

S-wave pairing in neutron matter is studied within an extension of correlated basis function (CBF) theory to include the strong, short range spatial correlations due to realistic nuclear forces and the pairing correlations of the Bardeen,…

Nuclear Theory · Physics 2008-11-26 Adelchi Fabrocini , Stefano Fantoni , Alexey Yu. Illarionov , Kevin E. Schmidt

We consider pairing in a dilute system of Fermions with a short-range interaction. While the theory is ill-defined for a contact interaction, the BCS equations can be solved in the leading order of low-energy effective field theory. The…

Nuclear Theory · Physics 2011-07-18 Thomas Papenbrock , George F. Bertsch