凝聚态物理

We study the dynamics of the relative phase following the connection of two independently formed Bose-Einstein condensates. Dissipation is assumed to be due to the creation of quasiparticles induced by a fluctuating condensate particle…

We study the anomalous diffusion phase $x ~ t^{\mu}$ with $0<\mu<1$ which exists both in the Sinai diffusion at small bias, and in the related directed trap model presenting a large distribution of trapping time $p(\tau) \sim…

A current of magnetic moments will flow in the spin-1/2 Heisenberg chain in the presence of an external magnetic field $B$ and a temperature gradient $\Delta T$ along the chain. We show that this magnetothermal effect is strictly {\em…

Motivated by novel results in the theory of complex adaptive systems, we analyze the dynamics of random walks in which the jumping probabilities are {\it time-dependent}. We determine the survival probability in the presence of an absorbing…

First principles calculations of the magnetic properties and the magneto-optical Kerr effect (MOKE) of iron thin films epitaxially grown on the [001] surface of paramagnetic metals: copper, silver, gold, palladium, and platinum are…

Members of boards of directors of large corporations who also serve together on an outside board, form the so called interlock graph of the board and are assumed to have a strong influence on each others' opinion. We here study how the size…

Recently K. Kavokin [Phys. Rev. B 64, 075305 (2001)] suggested that the Dzyaloshinskii-Moriya interaction between localized electrons governs slow spin relaxation in $n$-doped GaAs in the regime close to the metal-insulator transition. We…

We propose a method to probe states in the Mott insulator regime produced from a condensate in an optical lattice. We consider a system in which we create time-dependent number fluctuations in a given site by turning off the atomic…

In the moderately long wavelength propagation regime, acoustic crystaldevices which size is of several wave lengths are studied by using thefinite-difference time domain method. It is shown by the focusing and imaging of a square shaped…

We study the dynamical spin susceptibility $\chi ({\bf q},\omega)$ for spin-triplet superconductivity. We show that a large peak at $\omega = 2 \Delta$ appears in $\textrm{Im} \chi_{zz}({\mathbf{Q}}, \omega)$, where $z$ is the direction of…

We study the time-evolution of the scissors mode of a Bose-Einstein condensate during the ballistic expansion after release from the magnetic trap. We show that despite the nontrivial character of the superfluid expansion, the sinusoidal…

Recently, there has been a revival of interest in mechanisms for changing the spin polarization of an electron beam on transmission through, or reflection from, a magnetic surface. An understanding of these mechanisms would allow the use of…

We study the origin of the gap and the role of chemical composition in the half-ferromagnetic Heusler alloys using the full-potential screened KKR method. In the paramagnetic phase the C1_b compounds, like NiMnSb, present a gap. Systems…

Slow oscillations of the interlayer magnetoresistance observed in the layered organic metal $\beta $-(BEDT-TTF)$_2$IBr$_2$ are shown to originate from the slight warping of its Fermi surface rather than from independent small cyclotron…

A one-dimensional model of interacting electrons with on-site $U$, nearest-neighbor $V$, and pair-hopping interaction $W$ is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained…

We investigate the spatial patterns of the ground state of two interacting Bose-Einstein condensates. We consider the general case of two different atomic species (with different mass and in different hyperfine states) trapped in a magnetic…

Transmittance of the colossal magnetoresistive compound Nd_0.5Sr_0.5MnO_3 showing metal-insulator phase transition has been studied by means of the submm- and mm-wavelength band spectroscopy. An unusually high transparency of the material…

Collision process between breather and moving kink-soliton is investigated both analytically and numerically in Fermi-Pasta-Ulam (FPU) chains. As it is shown by both analytical and numerical consideration low amplitude breathers and soft…

We calculate the forces acting upon species adsorbed on a single wall carbon nanotube, in the presence of electric currents. We present a self consistent real space Green function method, which enables us to calculate the current induced…

Stochastic and coherence resonances appear in nonlinear systems subjected to an external source of noise and are characterized by a maximum response at the optimal value of the noise intensity. This paper shows experimentally that it is…