Related papers: Quantum Phase Fluctuations in High Tc Superconduct…
The mutual interaction between Cooper pairs is proposed as a mechanism for the superconducting state. Above $T_c$, pre-existing but fluctuating Cooper pairs give rise to the unconventional {\it pseudogap} (PG) state, well-characterized by…
For an electron gas with delta-function attraction we investigate the crossover from weak- to strong-coupling supercoductivity in two and three dimensions. We derive analytic expressions for the stiffness of phase fluctuations and set up…
A nematic quantum critical point is anticipated to exist in the superconducting dome of some high-temperature superconductors. The nematic order competes with the superconducting order and hence reduces the superconducting condensate at $T…
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…
The correlation function of the quantum fluctuations due to collective excitations is calculated and used to investigate the phase diffusion of a Bose-Einstein condensate close to zero temperature. It is shown that the phase diffusion time…
The hole-doped cuprate high temperature superconductors enter the pseudogap regime as their superconducting critical temperature, $T_c$, falls with decreasing hole density. Experiments have probed this regime for over two decades, but we…
We present a self-consistent approach to deal with the pairing-fluctuation effects in quasi-two-dimensional superconducting systems. Besides the Cooper pairs in the Bose-Einstein condensate, there are pairs occupying the excited states,…
Recent reflectivity measurements provide evidence for a "violation" of the in-plane optical integral in the underdoped high-T_c compound Bi_2Sr_2CaCu_2O_{8+\delta} up to frequencies much higher than expected by standard BCS theory. The sum…
In classical superconductors Cooper-pair formation and phase coherence occur simultaneously as the temperature is lowered below Tc. In high-temperature superconductors (HTSC), on the other hand, the small superfluid density and low…
Using matter-wave interference, we have investigated thermal phase fluctuations in narrow coplanar, concentric rings of ultracold fermionic superfluids. We found that the correlation length decreases with number density, consistent with…
In a two-band superconductor, two qualitatively different fluctuation modes related to the gap modules contribute to free energy and heat capacity, in addition to the phase fluctuations. The first mode has divergent temperature behaviour…
The occurrence of phase fluctuations due to thermal excitations in Bose-Einstein condensates (BECs) is studied for a variety of temperatures and trap geometries. We observe the statistical nature of the appearence of phase fluctuations and…
Assuming that the order parameter corresponds to an equal spin triplet pairing symmetry state, we calculate the effect of phase fluctuations in quasi-one-dimensional superconductors at high magnetic fields applied along the y (b') axis. We…
We study a two-dimensional superconductor in close proximity to a two-dimensional metallic sheet. The electrons in the superconducting sheet are coupled to those in the metallic sheet by the Coulomb interaction only. We obtain an effective…
A brief history is offered concerning the relation of magnetism to superconductivity, and the possibility that magnetic correlations are responsible for certain types of superconductors. A central focus is on high temperature cuprate…
Thermal fluctuations and disorder play an essential role in high-T$_c$ superconductors. After reviewing the mean-field phase diagram we describe significant modifications that result when the effects of finite temperature and disorder are…
The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density \rho_s in the BCS-BEC crossover regime of…
We discuss the instability of uniform superconducting states that contain the pairing correlations belonging to the odd-frequency symmetry class. The instability originates from the paramagnetic response of odd-frequency Cooper pairs and is…
We study the influence of dissipation on the switching current statistics of moderately damped Josephson junctions. Different types of both low- and high- $T_c$ junctions with controlled damping are studied. The damping parameter of the…
I discuss a proposed phase diagram of the cuprate superconductors as a function of temperature, carrier concentration, and a strong magnetic field perpendicular to the layers. I show how the phase diagram gives a unified interpretation of a…