Related papers: Universal scaling in BCS superconductivity in thre…
The solutions of a renormalized BCS model are studied in two space dimensions in $s$, $p$ and $d$ waves for finite-range separable potentials. The gap parameter, the critical temperature $T_c$, the coherence length $\xi$ and the jump in…
We consider the BCS energy gap $\Xi(T)$ (essentially given by $\Xi(T) \approx \Delta(T, \sqrt\mu)$, the BCS order parameter) at all temperatures $0 \le T \le T_c$ up to the critical one, $T_c$, and show that, in the limit of weak coupling,…
It is a remarkable property of BCS theory that the ratio of the energy gap at zero temperature $\Xi$ and the critical temperature $T_c$ is (approximately) given by a universal constant, independent of the microscopic details of the…
We consider the critical temperature for superconductivity, defined via the linear BCS equation. We prove that at weak coupling the critical temperature for a sample confined to a quadrant in two dimensions is strictly larger than the one…
The evolution from BCS to BEC superconductivity in the s-wave and d-wave channels is analyzed at zero temperature for a two-dimensional superconductor. Spectroscopic quantities for s-wave and d-wave systems present fundamental differences…
It is argued on the basis of the BCS theory that the zero-$T$ penetration depth satisfies $ \lambda^{-2}(0)\propto\sigma T_c $ ($\sigma$ is the normal state dc conductivity) not only in the extreme dirty limit $\xi_0/\ell \gg 1$, but in a…
By using multi-bands BCS theory, we have calculated the superconductivity energy gap and the critical temperature of a thin-film metallic superconductor. The thermodynamic superconducting characteristics such as critical magnetic field,…
Based on recent progress in mathematical physics, we present a reliable method to analytically solve the linearized BCS gap equation for a large class of finite-range interaction potentials leading to s-wave superconductivity. With this…
Understanding the pairing mechanism of unconventional superconductors remains a core challenge in condensed matter physics, particularly the ongoing debate over whether the related effects caused by electron-electron interactions unify…
The scaling of the conductivity at the superfluid-insulator quantum phase transition in two dimensions is studied by numerical simulations of the Bose-Hubbard model. In contrast to previous studies, we focus on properties of this model in…
We investigate the critical properties of cold bosonic gases in three dimensions, confined by an external quadratic potential coupled to the particle density, and realistically described by the Bose-Hubbard (BH) model. The trapping…
The superconducting instability in a non-Fermi liquid in $ d>1$ is considered. For a particular form of the single particle spectral function with homogeneous scaling $A(\Lambda k, \Lambda \omega) = \Lambda^{\alpha} A(k, \omega)$ it is…
Based on renormalization group arguments we establish that for a superconductor in the presence of a weak external magnetic field, $B$, the dependence on $B$ and the deviation from the critical temperature, $\tau$, of a thermodynamic…
Theoretically, we recently showed that the scaling relation between the transition temperature T_c and the superfluid density at zero temperature n_s (0) might exhibit a parabolic pattern [Scientific Reports 6 (2016) 23863]. It is…
We present a numerically exact solution for the BCS Hamiltonian at any temperature, including the degrees of freedom associated with classical phase, as well as amplitude, fluctuations via a Monte Carlo (MC) integration. This allows for an…
We describe high-Tc superconductivity in layered materials within a BCS theory as a BEC of massless-like Cooper pairons satisfying a linear dispersion relation, and propagating within quasi-2D layers of finite width defined by the charge…
We establish universal behavior in temperature dependencies of some observables in $(s+id)$-wave BCS superconductivity in the presence of a weak $s$ wave. There also could appear a second second-order phase transition. As temperature is…
Thin superconducting films form a unique platform for geometrically-confined, strongly-interacting electrons. They allow an inherent competition between disorder and superconductivity, which in turn enables the intriguing…
From the viewpoint of operator theory, we deal with the temperature dependence of the solution to the BCS gap equation for superconductivity. When the potential is a positive constant, the BCS gap equation reduces to the simple gap…
We present research on the superconducting properties of Nb$_{x}$Re$_{1-x}$ ($x$ = 0.13-0.38) obtained by measuring the electrical resistivity $\rho(T)$, magnetic susceptibility $\chi(T)$, specific heat $C_P(T)$, and London penetration…