The phenomenology of a LiFeAs superconductor can be explained in the framework of four-band s±-wave Eliashberg theory. We have examined the experimental data available in the literature and we have found that it is possible to reproduce the experimental critical temperature, the gap values and the upper critical magnetic field within an effective model in a moderately strong coupling regime tha...

We solve the 3D periodic Anderson model using a two impurity cluster dynamical mean field theory. We obtain the temperature versus hybridization phase diagram. Approaching the quantum critical point (QCP) both the Néel and lattice Kondo temperatures decrease and they do not cross at the lowest temperature we reached. While strong ferromagnetic spin fluctuation on the Kondo side is observed, our...

We present a quantitative analysis of finite frequency fluctuation conductivity above and below Tc in cuprate superconductors in zero dc magnetic field. In a YBa2Cu3O72d crystal showing a linear in temperature increase of the penetration depth at low temperatures, we find that two-dimensional ~2D! finite frequency Gaussian conductivity fluctuations above Tc cross over into a slower divergence o...

The implementation of a recently suggested class of structural change tests, which test for parameter instability in general parametric models, in the R language for statistical computing is described: Focus is given to the question how the conceptual tools can be translated into computational tools that reflect the properties and flexiblity of the underlying econometric metholody while being n...

Starting from a critical analysis of recently reported surprisingly large uncertainties in length and position measurements deduced within the framework of quantum gravity, we embark on an investigation both of the correlation structure of Planck scale fluctuations and the role the holographic hypothesis is possibly playing in this context. While we prove the logical independence of the fluctua...

Particle transport and its effect on the plasma density distribution remains an important, unresolved issue in magnetic fusion plasmas [1]. Fluctuating magnetic fields can arise from global tearing instabilities that often underlie the sawtooth oscillation [2] and lead to plasma relaxation [3]. Furthermore, magnetic fluctuations are also generated by energetic particles associated with non-indu...

We investigate the nonequilibrium behavior of the d-dimensional Ising model with purely dissipative dynamics during its critical relaxation from a magnetized initial configuration. The universal scaling forms of the two-time response and correlation functions of the magnetization are derived within the field-theoretical approach and the associated scaling functions are computed up to first orde...

Unconventional quantum criticality in heavy-fermion systems has been extensively analyzed in terms of a critical destruction of the Kondo effect. Motivated by a recent demonstration of quantum criticality in a mixed-valent heavy-fermion system, β-YbAlB(4), we study a particle-hole-asymmetric Anderson impurity model with a pseudogapped density of states. We demonstrate Kondo destruction at a mix...

We elaborate on several observable consequences of the Quantum-Critical-Point scenario. In particular we show that the strong k-dependent scattering of the quasiparticles with the quasi-critical charge and spin fluctuations reproduces the main features of the low-energy spectral weights and of the observed Fermi surfaces. In the underdoped cuprates the attractive k-dependent charge scattering d...

The temperature dependence o f the 81Br spin-lattice relaxation times for Cs2CdBr4 and Cs2HgBr4 was measured in the low temperature and the commensurate phases. For the com m en­ surate phase o f Cs2CdBr4 rapid shortening o f the T, o f vB ~ vc was observed on approaching the “lock-in” transition point. It is probably due to an anisotropic critical fluctuation. On the other hand, T, in the low ...