It is shown that a variational approach with fermionic squeezed states to manyfermion systems such as pairing model is one of useful methods beyond the usual Hartree-Fock-Bogoliubov approximation. A pairing-type quasi-spin squeezed state is constructed and adopted as a trial state in the variational method. By using this state, quantum fluctuations are taken into account. In pairing model, dyna...

We compare predictions of the mean-field theory of superconductivity for nearly antiferromagnetic and nearly ferromagnetic metals in two dimensions. The calculations are based on a parametrization of the effective interaction arising from the exchange of magnetic fluctuations. The Eliashberg equations for the transition temperature are solved including the full momentum dependence of the electr...

Cryptographic pairing (bilinear mapping) is a core algorithm for various cryptography protocols. It is computationally expensive and inefficiently computed with general purpose processors. Although there has been previous work looking into efficient hardware designs for pairing, most of these systems use small characteristic curves which are incompatible with practical software designs. In this...

We show that a chiral (f+if)-wave superconducting pairing may be induced in the lowest heavy hole band of a hole-doped semiconductor thin film through proximity contact with an s-wave superconductor. The chirality of the pairing originates from the 3π Berry phase accumulated for a heavy hole moving along a close path on the Fermi surface. There exist three chiral gapless Majorana edge states, i...

We investigate the effect of electron-electron interactions on proximity-induced s-wave superconductivity in one-dimensional nanowires. We treat the interactions on a self-consistent mean-field level, and find an analytic expression for the effective pairing potential in the presence of interactions, valid for a weakly tunnel coupled wire. We show that for a set of two nanowires placed in paral...

The separation method developed earlier by us [Nucl. Phys. A598 390 (1996)] to calculate and analyze solutions of the BCS gap equation for S0 pairing is extended and applied to P2– F2 pairing in pure neutron matter. The pairing matrix elements are written as a separable part plus a remainder that vanishes when either momentum variable is on the Fermi surface. This decomposition effects a separa...

The pairing interaction plays a crucial role in the nuclear mean-field model calculations. The most frequently used pairing type is the so-called monopole pairing interaction (g=const model). More realistic residual interactions are those with state-dependent matrix elements, e.g. δand Gogny forces. Previously the Gogny-type pairing force were studied within conventional Hartree-Fock-Bogoliubov...

A typical form of mass formula is re-explained in terms of nuclear structure. For N ≈ Z nuclei, we propose to start with the shell model picture and to consider the T = 0 2n − 2p (α-like) correlations in the first place, instead of the symmetry energy as a prior concept. Afterward, the symmetry energy is described on the basis of the α-like superfluidity caused by the T = 0 2n − 2p correlations...

How small can superconductors be? For isolated nanoparticles subject to quantum size effects, P.W. Anderson in 1959 conjectured that superconductivity could only exist when the electronic level spacing δ is smaller than the superconducting gap energy Δ. Here we report a scanning tunnelling spectroscopy study of superconducting lead (Pb) nanocrystals grown on the (110) surface of InAs. We find t...