Related papers: Self-Consistent Approximations for Superconductivi…
We present the derivation of an ab-initio and parameter free effective electron-electron interaction that goes beyond the screened RPA and accounts for superconducting pairing driven by spin-fluctuations. The construction is based on many…
The formation of Cooper pairs, a bound state of two electrons of opposite spin and momenta by exchange of a phonon [1], is a defining feature of conventional superconductivity. In the cuprate high temperature superconductors, even though it…
We propose a formalism to take account of the correction of the spatial fluctuations to the local self-energy obtained by the dynamical mean-field approximation. For this purpose, the approximate dynamical susceptibility in the framework of…
We investigate pseudo-gap phenomena realized in the BCS pairing model with a long but finite interaction range. We calculate the single-particle self-energy in all order exactly in the temperature range where the superconducting fluctuation…
Spin-splitting induced in a conventional superconductor weakens superconductivity by destroying spin-singlet and creating spin-triplet Cooper pairs. We demonstrate theoretically that such an effect is also caused by an adjacent compensated…
Rapid miniaturization of electronic devices and circuits demands profound understanding of fluctuation phenomena at the nanoscale. Superconducting nanowires -- serving as important building blocks for such devices -- may seriously suffer…
We study the superconducting transition temperature and the electronic properties of the metallic phase of $\kappa$-type (BEDT-TTF)$_2$X which shows unconventional properties in experiments, on the basis of the third order perturbation…
We bring forward a Green function approach for the prediction of Floquet topological phases in driven superconductor-semiconductor hybrids. Although it is common to treat the superconducting component as a mere Cooper-pair reservoir, it was…
Starting from H. Fr\"ohlich's second-quantized Hamiltonian for a $d$-dimensional electron gas in interaction with lattice phonons describing the quantum vibrations of a metal, we present a rigorous mathematical derivation of the…
We report on results of our theoretical study of the in-plane infrared conductivity of the high-Tc cuprate superconductors using the model where charged planar quasiparticles are coupled to spin fluctuations. The computations include both…
We investigate the role of disorder on the superconducting (SC) fluctuation in short coherence length d-wave superconductors. The particular intetest is focused on the disorder-induced microscopic inhomogeneity of SC fluctuation and its…
A characteristic feature of the Gaussian approximation in the functional-integral approach to the spin-fluctuation theory is the jump phase transition to the paramagnetic state. We eliminate the jump and obtain a continuous second-order…
The leading superconducting instabilities of the two-dimensional extended repulsive one-band Hubbard model within spin-fluctuation pairing theory depend sensitively on electron density, band and interaction parameters. We map out the phase…
In this work, a Josephson relation is generalized to a multi-component fermion superfluid. Superfluid density is expressed through a two-particle Green function for pairing channels. When the system has only one gapless collective…
Synthetic platforms afford an unparalleled degree of controllability in realizing strongly-correlated phases of matter. In this work, we study the possibility of electrically tunable exciton-mediated superconductivity arising in…
Based on an attractive $U$ Hubbard model on a lattice with up to second neighbor hopping we derive an effective Hamiltonian for phase fluctuations. The superconducting gap is assumed to have s-wave symmetry. The effective Hamiltonian we…
We examine the effect of classical magnetic fluctuations on the phase diagram of paramagneticallylimited two-dimensional superconductors under a Zeeman magnetic field. We derive the free energy expansion in powers of the superconducting…
In a previous article, we have investigated the non-equilibrium two-level Anderson model with a simple iterative perturbation theory. Here we use here a more sophisticated perturbative method, the fluctuation-exchange (FLEX) approximation.…
Superconductors are often discussed in the mean-field approximation that breaks $U(1)$ symmetry. Since the $U(1)$ symmetry underlies the charge conservation, naive application of response theory sometimes gives results that are not…
We first argue that the collective behaviour of the Cooper pairs created by thermal fluctuations well above the superconducting transition temperature, Tc, is dominated by the uncertainty principle which, in particular, leads to a…