In this note, a novel BCS-type formalism is constructed in the framework of a schematic QCD inspired quark model, having in mind the description of color symmetrical superconducting states. The physical properties of the BCS vacuum (average numbers of quarks of different colors) remain unchanged under an arbitrary color rotation. In the usual approach to color superconductivity, the pairing cor...

The recent proposal to determine the (exact) correlation energy based on pairing matrix fluctuations by van Aggelen et al. ["Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation," preprint arXiv:1306.4957 (2013)] revived the interest in the simplest approximation along this path: the particle-particle random phase approximation (pp-RPA...

Cooper pairing instability in a Fermi liquid is well understood by the BCS theory, but pairing mechanism for doped Mott insulators still remains elusive. Previously it has been shown by density matrix renormalization group (DMRG) method that a single doped hole is always self-localized due to the quantum destructive interference of the phase string signs hidden in the t-J ladders. Here we repor...

We discuss the possibility that heavy fermion superconductors involve odd-frequency triplet pairing. A key technical innovation in this discussion is a Majorana representation for the local moments which enables the n f = 1 constraint in the Kondo lattice to be handled without a Gutzwiller approximation. Our mean field theory for odd frequency pairing involves a condensation of local moments an...

We have performed an angle-resolved photoemission spectroscopy study of the new superconductor Ba0.6K0.4Fe2As2 in the low energy range. We report the observation of an anomaly around 25 meV in the dispersion of superconducting Ba0.6K0.4Fe2As2 samples that nearly vanishes above T_{c}. The energy scale of the related mode (13+/-2 meV) and its strong dependence on orbital and temperature indicates...

We describe the first version (v1.00) of the code hfbrad which solves the SkyrmeHartree-Fock or Skyrme-Hartree-Fock-Bogolyubov equations in the coordinate representation within the spherical symmetry. A realistic representation of the quasiparticle wave functions on the space lattice allows for performing calculations up to the particle drip lines. Zero-range density-dependent interactions are ...

Near Feshbach resonances, n|a|3 ≫ 1, systems of Bose and Fermi particles become strongly interacting/dense. In this unitary limit both bosons and fermions have very different properties than in a dilute gas, e.g., the energy per particle approach a value h̄n2/3/m times an universal many-body constant. Calculations based upon an approximate Jastrow wave function can quantitatively describe recent...

We point out that the proton-neutron energy contribution, for low multipoles (in particular for the quadrupole component), effectively renormalizes the strength of the pairing interaction acting amongst identical nucleons filling up a single-j or a set of degenerate manyj shells. We carry out the calculation in lowest-order perturbation theory. We perform a study of this correction in various m...

We propose a scheme based on topological insulators to generate Kramers pairs of Majorana fermions or parafermions in the complete absence of magnetic fields. Our setup consists of two topological insulators whose edge states are brought close to an s-wave superconductor. The resulting proximity effect leads to an interplay between a nonlocal crossed Andreev pairing, which is dominant in the st...

To study collective motion, the extended pairing plus QQ force model proposed recently is applied to A=46, 48 and 50 nuclei in the f p shell region. Exact shell model calculations in the truncated model space (f 7/2 , p 3/2 , p 1/2) prove the usefulness of the interaction. The simple model with the pairing plus quadrupole pairing plus QQ force and J-independent isoscalar proton-neutron force re...