Other Condensed Matter
Thin PbTe films (thickness 500 - 600 angstrom), deposited on SrTiO3, have been investigated by electric field effect (EFE). The high resistivity of such thin films warrants a high sensitivity of the EFE method. The SrTiO3 substrate serves…
We study a system whose dynamics are governed by predictions of its future states. A general formalism and concrete examples are presented. We find that the dynamical characteristics depend on how to shape the predictions as well as on how…
We perform the first numerical three-dimensional studies of quantum field effects in the Bosenova experiment on collapsing condensates by E. Donley et al. [Nature 415, 39 (2002)] using the exact experimental geometry. In a stochastic…
We extended McMillan's Green's function method to study the equilibrium spin current (ESC) in a ferromagnet/ferromagnet (FM/FM) tunnelling junction, in which the magnetic moments in both FM electrodes are not collinear. The single-electron…
We have measured the planar Hall effect in epitaxial thin films of the itinerant ferromagnet SrRuO3 patterned with their current paths at different angles relative to the crystallographic axes. Based on the results, we have determined that…
We report the realization of a Bose-Einstein condensate (BEC) in the hydrodynamic regime. The hydrodynamic regime is reached by evaporative cooling at a relative low density suppressing the effect of avalanches. With the suppression of…
We present coherence-enhanced imaging, an in situ technique that uses Raman superradiance to probe the spatial coherence properties of an ultracold gas. Applying this method, we obtain a spatially resolved measurement of the condensate…
We study the splitting of a harmonically trapped atomic Bose-Einstein condensate when we continuously turn up an optical lattice (or a double-well) potential. As the lattice height is increased, quantum fluctuations of atoms are enhanced.…
The electronic properties of one-dimensional clusters of N atoms or molecules have been studied. The model used is similar to the Kronig-Penney model with the potential offered by each ion being approximated by an attractive delta function.…
Computer simulations of first-order relaxation processes show that the spatial configurations of the system acquire an invariant shape once the stationary regime is attained. Inspired by them we find that, in any first-order relaxation…
This paper presents the ultra-wideband (UWB) on-body radio channel modelling using a sub-band Finite-Difference Time-Domain (FDTD) method and a model combining the uniform geometrical theory of diffraction (UTD) and ray tracing (RT). In the…
The quantum dynamics of colliding Bose-Einstein condensates with 150 000 atoms are simulated directly from the Hamiltonian using the stochastic positive-P method. Two-body correlations between the scattered atoms and their velocity…
Artificially confined, small quantum systems show a high potential for employing quantum physics in technology. Ultra-cold atom gases have opened an exciting laboratory in which to explore many-particle systems that are not accessible in…
We compare the collective modes for Bose-condensed systems with two degenerate components with and without spontaneous intercomponent coherence at finite temperature using the time-dependent Hartree-Fock approximation. We show that the…
We present a Lagrangian formalism to the dissipative system of a charge interacting with its own radiation field, which gives rise to the radiation damping \cite{Heitler}, by the indirect representation doubling the phase-space dimensions.
We use the time-dependent mean-field Gross-Pitaevskii equation to study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-one-dimensional Bose-Einstein condensate (BEC). Because of three-body…
Time-dependent density functional theory is thought to work well for the test cases of He and Be atoms. We perform a quantum defect analysis of the s, p, and d Rydberg states of Be with accurate ground state Kohn-Sham potentials. The s- and…
We are developing Nb diffusion-cooled Hot Electron Bolometers (HEBs) for a large-format array submillimeter camera. We have fabricated Nb HEBs using a new angle deposition process. We have characterized these devices using heterodyne mixing…
Continuous and pulsed quantum Zeno effects were observed using a $^{87}$Rb Bose-Einstein condensate(BEC). Oscillations between two ground hyperfine states of a magnetically trapped condensate, externally driven at a transition rate…
Based on a recent progress in nonequilibrium statistical mechanics of infinitely extended quantum systems, a nonequlibrium steady state (NESS) is constructed for a single-level quantum dot interacting with two free reservoirs under less…