凝聚态物理
The crossover from nonadiabatic to adiabatic electron transfer has been theoretically studied under a spin-boson model (dissipative two-state system) description. We present numerically exact data for the thermal transfer rate and the…
We report the production of matter-wave solitons in an ultracold lithium 7 gas. The effective interaction between atoms in a Bose-Einstein condensate is tuned with a Feshbach resonance from repulsive to attractive before release in a…
We report on the optical manipulation of the electron spin relaxation time in a GaAs based heterostructure. Experimental and theoretical study shows that the average electron spin relaxes through hyperfine interaction with the lattice…
The electronic polarization energies, P = (P+) + (P-), of a PTCDA (perylenetetracarboxylic acid dianhydride) cation and anion in a crystalline thin film on a metallic substrate are computed and compared with measurements of the PTCDA…
The momentum distribution of the unpolarized uniform electron gas in its Fermi-liquid regime, n(k,r_s), with the momenta k measured in units of the Fermi wave number k_F and with the density parameter r_s, is constructed with the help of…
The interplay between spin and charge transport in electrically and magnetically inhomogeneous semiconductor systems is investigated theoretically. In particular, the theory of spin-polarized bipolar transport in magnetic p-n junctions is…
It is well known that the particles in a beam of Boson obeying Bose-Einstein statistics tend to cluster (bunching effect), while the particles in a degenerate beam of Fermion obeying Fermi-Dirac statistics expel each other (anti-bunching…
An independent pair ansatz is developed for the many body wavefunction of dilute Bose systems. The pair correlation is optimized by minimizing the expectation value of the full hamiltonian (rather than the truncated Bogoliubov one)…
The purpose of the present work is to apply the method recently developed in reference [chain_m] to the spin-1 Ising chain, showing how to obtain analytical $\beta$-expansions of thermodynamical functions through this formalism. In this…
We investigate the nature of quantum entanglement in long-range orders and spontaneous symmetry breaking. It is shown that diminishing of entanglement between the condensate mode and the rest of the system underlies off-diagonal long-range…
Comment on "Are financial crashes predictable?", L. Laloux, M. Potters, R. Cont, J.P Aguilar and J.-P. Bouchaud, Europhys. Lett. 45, 1-5 (1999)
We relate the entropies of ensembles of atoms in optical lattices to atoms in simple traps. We then determine which ensembles of lattice-bound atoms will adiabatically transform into a Bose condensate. This shows a feasible approach to Bose…
The dynamics of the S&P500 price signal is studied using a moving average technique. Particular attention is paid to intersections of two moving averages with different time horizons. The distributions of the slopes and angle between two…
The thermal diffusivity of a Bi-2212 polycrystalline sample has been measured under a 1T magnetic field applied perpendicularly to the heat flux. The magnetic contribution to the heat carrier mean free path has been extracted and is found…
Recent neutron scattering experiments on CsNiCl_3 reveal some features which are not well described by the nonlinear sigma model nor by numerical simulations on isolated S=1 spin chains. In particular, in real systems the intensity of the…
We discuss the adiabatic self-trapping of small polarons within the density functional theory (DFT). In particular, we carried out plane-wave pseudo-potential calculations of the triplet exciton in NaCl and found no energy minimum…
We report on calculations of the formation energies of several [100] and [110] oriented step structures on biaxially stressed Si and Ge (001) surfaces. It is shown that a novel rebonded [100] oriented single-height step is strongly…
In an inhomogeneously doped magnetic semiconductor spin relaxation time T_1 can be determined by all-electrical measurements. Nonequilibrium spin injected in a magnetic p-n junction gives rise to the spin-voltaic effect where the…
Effect of oscillations of the vibration amplitude of cylindrical sample suspended by a thin elastic thread and vibrating in a transverse magnetic field and containing 2D quasi-two-dimensional vortices (pancakes), was observed in the…
Using the full-potential screened Korringa-Kohn-Rostoker method we study the full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these compounds show a half-metallic behavior, however in contrast to the half-Heusler alloys…