其他凝聚态物理
The quantum-classical Liouville equation describes the dynamics of a quantum subsystem coupled to a classical environment. It has been simulated using various methods, notably, surface-hopping schemes. A representation of this equation in…
Experimental observation of superfluidity in a microscopic cluster, $M:(^4He)_x$, of a molecule ($M$) and $x$ number of $^4He$ atoms (with $x$ ranging from 1 to many) is qualitatively analyzed. It concludes that: (i) each $^4He$ atom in the…
The introduction of liquid 3He into silica aerogel provides us a with model system in which to study the effects of disorder on the properties of a strongly correlated Fermi liquid. The transport of heat, mass and spin exhibits cross-over…
Tunneling between a photo-excited p-type silicon tip and a gold surface is studied as a function of tip bias, tip/sample distance and light intensity. In order to extend the range of application of future spin injection experiments, the…
The nonlinear Schroedinger equation is studied for a periodic sequence of delta-potentials (a delta-comb) or narrow Gaussian potentials. For the delta-comb the time-independent nonlinear Schroedinger equation can be solved analytically in…
We have measured the frequency-dependent, complex impedance of thin metal strips in a broad range of microwave frequencies (45~MHz to 20~GHz). The spectra are in good agreement with theoretical predictions of an RCL model. The resistance,…
Plasmonics has been attracting considerable interest as it allows localization of light at nanoscale dimensions. A breakthrough in integrated nanophotonics can be obtained by fabricating plasmonic functional materials. Such systems may show…
We report a first attempt to produce metastable hcp solid helium below its melting pressure. A focused sound pulse is emitted along the c-axis of a mono-domain hcp helium-4 crystal starting from a static pressure just above the melting…
Sonoluminescence occurs when tiny bubbles rilled with noble gas atoms are driven by a sound wave. Each cycle of the driving field is accompanied by a collapse phase in which the bubble radius decreases rapidly until a short but very strong…
It is widely believed that the generation of high speed optical signals is not the job for an LED. However this work is done to show that there are techniques which can be used to produce nanosecond square pulses from a diode. Rise and fall…
In this paper we study the effect of positional randomness on transmissional properties of a two dimensional photonic crystal as a function of a randomness parameter $\alpha$ ($\alpha=0$ completely ordered, $\alpha=1$ completely…
In this paper we introduce a novel 3D Lattice-Boltzmann model that recovers in the continuous limit the Maxwell equations in materials. In order to build conservation equations with antisymmetric tensors, like the Faraday law, the model…
We introduce an efficient method to solve the Mott-Hubbard model. The Schr\"{o}dinger equation is solved by the successive construction of doorway states. The ground state wavefunction derived by this method contains all relevant many-body…
Physical reality of the existence of electron bubble in liquid $^4He$ (or $^3He$) renders a {\it clear experimental evidence} for a quantum particle (in an interacting environment as seen by electron in liquid helium) to occupy exclusively…
Isotropic antiferromagnets shows a reach variety of magnetic solitons with non-trivial static and dynamic properties. One-dimensional soliton elementary excitations have a periodic dispersion law. For two-dimensional case, planar…
We develop a pairing mean-field theory to describe the quantum dynamics of the dissociation of molecular Bose-Einstein condensates into their constituent bosonic or fermionic atoms. We apply the theory to one, two, and three-dimensional…
We analyze time-resolved spontaneous emission from excitons confined in self-assembled $\mathrm{InAs}$ quantum dots placed at various distances to a semiconductor-air interface. The modification of the local density of optical states due to…
We report theoretical studies of charge transport in single-stranded DNA in the direction perpendicular to the backbone axis. We find that, if the electrodes which sandwich the DNA have the appropriate spatial width, each nucleotide carries…
An effect of laser-cooling of water was observed for the first time with a temperature decrease dT = -2.2 K after irradiation of liquid water surface by a powerful Ar-Xe pulse laser with a pulse energy of about 1 J and wavelength L = 1.73,…
Quantum phases with unusual symmetries may play a key role for the understanding of solid state systems at low temperatures. We propose a realistic scenario, well in reach of present experimental techniques, which should permit to produce a…