We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and applied it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form e−αTt ln[t/t0...

We have successfully employed the recently observed quasiparticle admittance of a superconducting tunnel junction as the tuning element for a superconductorinsulator-superconductor mixer. This is the first demonstration of an electronic on-chip tuning element for a superconducting detector. We observe an increase in the dynamic resistance and an improvement in mixer gain and noise temperature a...

Within the framework of the kinetic energy driven superconducting mechanism, the momentum dependence of the Bogoliubov angle in the electron-doped cuprate superconductors is studied. By calculation of the ratio of the low energy quasiparticle spectra at positive and negative energies, it is shown that the Bogoliubov angle increases monotonically across the Fermi crossing point, suggesting a con...

The problem of the microscopic description of excited states of the even-even openshell atomic nuclei is considered. A model is formulated which allows one to go beyond the quasiparticle random phase approximation. The physical content of the model is determined by the quasiparticle time blocking approximation (QTBA) which enables one to include contributions of the two-quasiparticle and the tw...

We report a theoretical study of the quasiparticle lifetime and the quasiparticle mean free path caused by inelastic electron-electron scattering in ferromagnetic compounds of the Co-Fe and Ni-Fe systems. The study is based on spin-polarized calculations, which are performed within the GW 0 approximation for equiatomic and Co(Ni)-rich compounds, as well as for their constituents. We mainly focu...

We analyze the properties of the quasiparticle excitations of metallic antiferromagnetic states in a strongly correlated electron system. The study is based on dynamical mean field theory (DMFT) for the infinite dimensional Hubbard model with antiferromagnetic symmetry breaking. Self-consistent solutions of the DMFT equations are calculated using the numerical renormalization group (NRG). The l...

Tunneling spectroscopy measurements are reported on optimally-doped and overdoped Bi2Sr2CaCu2O8+δ single crystals. A novel point contact method is used to obtain superconductor-insulator-normal metal (SIN) and SIS break junctions as well as intrinsic Josephson junctions (IJJ) from nanoscale crystals. Three junction types are obtained on the same crystal to compare the quasiparticle peaks and hi...

Injection-detection experiments have been performed to study quasiparticle diffusion and quasiparticle losses in Nb strips using a series array of Nb/AI junctions. The I-Vcurve of the detector junction was measured as a function of the spacing between the (high-quality) detector junction and the simultaneously biased injector junction. For our sample geometry, the quasiparticle gas is described...

The levels of Te125 have been studied using Sb125 nuclei, polarized at T=O.014°K in an iron lattice, and Ge (Li) detectors. The magnetic moment of Sb125 was determined as (2.59±O.03) PtN. Levels (spins) were assigned at 35.9(1+), 145.4(lj-), 322.2(j-), 443.7(probably i+), 462.5(!+), 525.4(probably !-), 636.1 (i+), 642.3 (i+), 671.6(!+) (energies in keY). The even-parity levels could be identifi...

We test the quark mass dependence implemented in the quasiparticle dispersion relations of our quasiparticle model for the QCD equation of state by comparing with recently available lattice QCD data near Tc employing almost physical quark masses. In addition, we emphasize the capability of our model to successfully describe lattice QCD results for imaginary chemical potential and to analyticall...