It was shown recently that the Fe magnetization reversal in the Fe/MnAs/GaAs(001) epitaxial system, attained by temperature control of the regular stripe pattern of the MnAs αand β-phases, can also be driven by an ultrashort optical laser pulse. In the present time-resolved scattering experiment, we address the dynamics of the MnAs α-β self-organized stripe pattern induced by a 100 fs optical l...

For uniform systems of spin-less fermions in d spatial dimensions with d > 1, interacting through the isotropic two-body potential v(r − r), a celebrated theorem due to Luttinger (1961) states that under the assumption of validity of the many-body perturbation theory the self-energy Σ(k; ε), with 0 ≤ k∼3kF (where kF stands for the Fermi wavenumber), satisfies the following universal asymptotic ...

For systems of electrons that can exchange energy and particles with a large medium, the celebrated Fermi Dirac (FD) distribution provides the probability for an electron to occupy a given energy level after the total energy of the system has been increased. This powerful tool derives from the laws of statistical mechanics (see, e.g., Landau and Lifchitz [3]). But this result does not apply to ...

I review the current status of Fermi acceleration theory at relativistic shocks. I first discuss the relativistic shock jump conditions, then describe the nonrelativistic Fermi mechanism and the differences introduced by relativistic flows. I present numerical calculations of the accelerated particle spectrum, and examine the maximum energy attainable by this process. I briefly consider the min...

Based on the Bogoliubov non-ideal gas model, we discuss the energy spectrum and phase transition of the superfluid Fermi gas of atoms with a weak attractive interaction on the canonical noncommutative space. Because the interaction of a BCS-type superfluid Fermi gas originates from a pair of Fermionic quasi-particles with opposite momenta and spins, the Hamiltonian of the Fermi gas on the nonco...

We consider the interplay between superconducting (SC) and commensurate spin-density-wave (SDW) orders in iron pnictides by analyzing a multiple-order Ginzburg–Landau free energy. We are particularly interested in whether the doping-induced transition between the two states is first order or whether the two pure phases are separated by an intermediate phase with coexisting SC and SDW orders. Fo...

For quantum systems described by Schrödinger operators on the half-space Rd−1×R≤0 the boundary force per unit area and unit energy is topologically quantised provided the Fermi energy lies in a gap of the bulk spectrum. Under this condition it is also equal to the integrated density of states at the Fermi energy.

A new Density-Functional (DF) formula is constructed for atoms. The kinetic energy of the electrons is divided into two parts: the kinetic self-energy and the orthogonalization energy where these concepts are borrowed from the pseudopotential theory. For the radial part of the orthogonalization energy which replaces the radial part of the Fermi-energy of the Thomas-Fermi model we derived the ex...

We derive error estimates in the appropriate norms, for the streamlinediffusion (SD) finite element methods for steady state, energy dependent,Fermi equation in three space dimensions. These estimates yield optimal convergencerates due to the maximal available regularity of the exact solution.High order SD method together with implicit integration are used. The formulationis strongly consistent...

The transition metal dichalcogenide 1T-TaS2 is a layered material exhibiting charge density waves. Based on angleresolved photoemission experiments mapping spectral weight at the Fermi surface and density functional theory calculations we discuss possible mechanisms involved with the creation of charge density waves. At first the flat parts of the elliptically shaped Fermi surface appear to pla...