Related papers: Eliashberg Theory in the Weak Coupling Limit
The emergence of near-ambient temperature superconductivity under pressure in the metal hydride systems has motivated a desire to further understand such remarkable properties, specifically critical magnetic fields. YH$_6$ is suggested to…
When the electron-phonon coupling is quadratic in the phonon coordinates, electrons can pair to form bipolarons due to phonon zero-point fluctuations, a purely quantum effect. We study superconductivity originating from this pairing…
We investigate the Josephson effect between two coupled superconductors, coupled by the tunneling of pairs of electrons, in the regime that their energy level spacing is comparable to the bulk superconducting gap, but neglecting any…
Alkali-doped fullerides are molecular-based superconductors with multiple active orbitals. In this paper, using the Eliashberg theory with the retardation effect of Jahn-Teller phonons, we study the response of the spin-singlet…
We report $ab~initio$ calculations of the electronic and vibrational properties in CuPb$_9$(PO$_4$)$_6$O, including the electron-phonon coupling strength via strong-coupling Migdal-Eliashberg theory. We verify the presence of appealing flat…
It is argued that the origin of the buckling of the CuO$_{2}$ planes in certain cuprates as well as the strong electron-phonon coupling of the $B_{1g}$ phonon is due to the electric field across the planes induced by atoms with different…
In the main part of this PhD thesis, we consider a periodically realized microscopic superconductor described by BCS theory, which is subject to external electromagnetic fields. We show that the superconductor is properly described by…
The BCS theory of superconductivity named electron-phonon interaction as a glue that overcomes Coulomb repulsion and binds fermions into pairs which then condense and superconduct. We review recent and not so recent works aiming to…
We have shown that the weak-coupling limit superconductors are well described by $ q \sim 1 $, where $ q $ is a real parameter which characterizes the degree of nonextensivity of Tsallis' entropy. Nevertheless, small deviations with respect…
The superconducting pairing instability---as determined by a divergence of the two-particle susceptibility---is obtained in the mean field (BCS) approximation in the thermodynamic limit. The usual practice is to examine this property for a…
There is rich experimental evidence that granular superconductors and superconducting films often exhibit a higher transition temperature, $T_{c}$, than that in bulk samples of the same material. This paper suggests that this enhancement…
In the standard model (SM), the coupling of the Higgs boson to electrons is real and very small, proportional to the electron mass. New physics could significantly modify both real and imaginary parts of this coupling. We discuss…
Near a quantum critical point (QCP) in a metal, strong Fermion-Fermion interactions mediated by soft collective bosons give rise to two competing phenomena: non-Fermi liquid behavior and superconductivity that deviates from conventional BCS…
Weak-coupling expansions (conserving approximations) are carried out for the attractive Holstein and Hubbard models (on an infinite-dimensional hypercubic lattice) that include all bandstructure and vertex correction effects. Quantum…
The paper is devoted to the effects of superconducting pairing in small metallic grains. It turns out that at strong superconducting coupling and in the limit of large Thouless conductance one can explicitly determine the low energy…
We theoretically predict and experimentally observe the onset of weak-link physics in the dynamical response of transition edge sensors (TES). We develop a theoretical framework based on a Fokker-Planck description that incorporates both…
Attempts to explain correlated-electron superconductivity have largely focused on the proximity of the superconducting state to antiferromagnetism. Yet, there exist many correlated-electron systems that exhibit insulator-superconducting…
We study the superconducting instability mediated by spin fluctuations in the Eliashberg theory for a minimal two-band model of iron-based superconductors. While antiferromagnetic spin fluctuations can drive superconductivity (SC) as is…
We discuss the compatibility of the most accurate experimental data with the ordinary Migdal-Eliashberg theory of superconductivity in the fullerene compound Rb_3C_60. By using different model phonon spectra we conclude that the…
We report partial progress on the weak coupling limit behavior of observables for the periodic quantum Lorentz gas. Our results indicate that for certain observables, the limit behavior is trivial and can be described via a transport…