Separable Structure of Many-Body Ground-State Wave Function

We have investigated a general structure of the ground-state wave function for the Schr\"odinger equation for $N$ identical interacting particles (bosons or fermions) confined in a harmonic anisotropic trap in the limit of large $N$. It is shown that the ground-state wave function can be written in a separable form. As an example of its applications, this form is used to obtain the ground-state wave function describing collective dynamics for $N$ trapped bosons interacting via contact forces.Comment: J. Phys. B: At. Mol. Opt. Phys. 33 (2000) (accepted for publication

Anomalous Hall effect for the phonon heat conductivity in paramagnetic dielectric

The theory of anomalous Hall effect for the heat transfer in a paramagnetic dielectric, discovered experimentally in [1], is developed. The appearance of the phonon heat flux normal to both the temperature gradient and the magnetic field is connected with the interaction of magnetic ions with the crystal field oscillations. In crystals with an arbitrary phonon spectrum this interaction creates the elliptical polarization of phonons. The kinetics related to phonon scattering induced by the spin-phonon interaction determines an origin of the off-diagonal phonon density matrix. The combination of the both factors is decisive for the phenomenon under consideration.Comment: 5 pages; typos and abstract correcte

Growth and crystallization of molybdenum layers on amorphous silicon

The structure of molybdenum layers deposited by direct current magnetron sputtering onto the amorphous silicon (a-Si) layers as function of nominal layer thickness was studied by methods of transmission electron microscopy. Molybdenum layers with nominal thickness 1.5btMo nomb1.9 nm consist of clusters which should be considered as a transient state between strongly disordered (amorphous) state and crystal one. A transition from clusters to polycrystals takes place within the thickness range of 1.9btMo nomb2.5 nm. Resulting Mo crystallites have an inequiaxial form with dimensions of (3–4)×(15–30)nm2 and consist of blocks. The lateral axis of inequiaxial crystallites is parallel to 110 direction. As the metal layer thickness increases Mocrystallites take the more regular form at the expense of recrystallization

Matching of nonthermal initial conditions and hydrodynamic stage in ultrarelativistic heavy-ion collisions

A simple approach is proposed allowing actual calculations of the preequilibrium dynamics in ultrarelativistic heavy-ion collisions to be performed for a far-from-equilibrium initial state. The method is based on the phenomenological macroscopic equations that describe the relaxation dynamics of the energy-momentum tensor and are motivated by Boltzmann kinetics in the relaxation-time approximation. It gives the possibility to match smoothly a nonthermal initial state to the hydrodynamics of the quark gluon plasma. The model contains two parameters, the duration of the prehydrodynamic stage and the initial value of the relaxation-time parameter, and allows one to assess the energy-momentum tensor at a supposed time of initialization of the hydrodynamics.Comment: 16 pages, minor corrections, to appear in Phys. Rev.

Quantum dynamics in canonical and micro-canonical ensembles. Part I. Anderson localization of electrons

The new numerical approach for consideration of quantum dynamics and calculations of the average values of quantum operators and time correlation functions in the Wigner representation of quantum statistical mechanics has been developed. The time correlation functions have been presented in the form of the integral of the Weyl's symbol of considered operators and the Fourier transform of the product of matrix elements of the dynamic propagators. For the last function the integral Wigner- Liouville's type equation has been derived. The numerical procedure for solving this equation combining both molecular dynamics and Monte Carlo methods has been developed. For electrons in disordered systems of scatterers the numerical results have been obtained for series of the average values of the quantum operators including position and momentum dispersions, average energy, energy distribution function as well as for the frequency dependencies of tensor of electron conductivity and permittivity according to quantum Kubo formula. Zero or very small value of static conductivity have been considered as the manifestation of Anderson localization of electrons in 1D case. Independent evidence of Anderson localization comes from the behaviour of the calculated time dependence of position dispersion.Comment: 8 pages, 10 figure

Exponential Decay of Correlations in a Model for Strongly Disordered 2D Nematic Elastomers

Lattice Monte-Carlo simulations were performed to study the equilibrium ordering in a two-dimensional nematic system with quenched random disorder. When the disordering field, which competes against the aligning effect of the Frank elasticity, is sufficiently strong, the long-range correlation of the director orientation is found to decay as a simple exponential, Exp[-r/x]. The correlation length {x} itself also decays exponentially with increasing strength of the disordering field. This result represents a new type of behavior, distinct from the Gaussian and power-law decays predicted by some theories.Comment: Latex file (4 pages) + 2 EPS figure

Sea buckthorn cultivars promising for mechanized harvesting by cutting fruit-bearing branches

Background. Sea buckthorn (Hippophae rhamnoides L.) is the main berry crop in the horticultural production of Altai Territory and occupies the largest growing area among berries in Russia. Meanwhile, further expansion of commercial plantations is limited by known bottlenecks in harvesting. In this context, new technological solutions in harvest mechanization are considered one of the primary tasks. A promising way is the cutting of fruit-bearing branches. At the same time, the development of cultivars suitable for such harvesting technique is very important.Materials and methods. Thirteen cultivars and selected forms of sea buckthorn developed at the Federal Altai Scientific Center of Agro-Biotechnologies were taken as research material. To evaluate the productivity of top branches, three of them with a length of 70–100 cm were cut from the plants of each accession. Fruit detachment force was assessed using a Dina-2 device. Dispersion analysis was applied for statistical interpretation.Results. Productivity of top branches as well as agronomic and biological characteristics of sea buckthorn fruits were studied. Accessions 87-93-1, 111-05-3 and 378-06-1 were identified for high productivity of their top branches and for predomination of the generative part over the vegetative one. The highest number of berries per bud (5.4–5.9 pieces) was observed in accessions 87-93-4, 32-01-1, 378-06-1 and 111-05-3. Cv. ‘Afina’ demonstrated for its high level of vegetative and generative productivity. Selected forms 111-05-3, 32-01-1 and 4-93-11 with low fruit detachment force (136.8–155.1 g) are promising for shaking without prior freezing.Conclusion. Selected forms 111-05-3, 378-06-1 and 32-01-1 were recognized as most promising for harvesting by branch cutting

Diffusion-jump model for the combined Brownian and Neel relaxation dynamics of ferrofluids in the presence of external fields and flow

Relaxation of suspended magnetic nanoparticles occurs via Brownian rotational diffusion of the particle as well as internal magnetization dynamics. The latter is often modeled by the stochastic Landau-Lifshitz equation, but its numerical treatment becomes prohibitively expensive in many practical applications due to a time-scale separation between fast, Larmor-type precession and slow, barrier-crossing dynamics. Here, a diffusion-jump model is proposed to take advantage of the time-scale separation and to approximate barrier-crossings as thermally activated jump processes that occur alongside rotational diffusion. The predictions of our diffusion-jump model are compared to reference results obtained by solving the stochastic Landau-Lifshitz equation coupled to rotational Brownian motion. Good agreement is found in the regime of high energy barriers where Neel relaxation can be considered a thermally activated rare event. While many works in the field have neglected N\'eel relaxation altogether, our approach opens the possibility to efficiently include Neel relaxation also into interacting many-particle models

Ground-State of Charged Bosons Confined in a Harmonic Trap

We study a system composed of N identical charged bosons confined in a harmonic trap. Upper and lower energy bounds are given. It is shown in the large N limit that the ground-state energy is determined within an accuracy of $\pm 8$ and that the mean field theory provides a reasonable result with relative error of less than 16% for the binding energy .Comment: 15 page

The Boltzmann equation for colourless plasmons in hot QCD plasma. Semiclassical approximation

Within the framework of the semiclassical approximation, we derive the Boltzmann equation describing the dynamics of colorless plasmons in a hot QCD plasma. The probability of the plasmon-plasmon scattering at the leading order in the coupling constant is obtained. This probability is gauge-independent at least in the class of the covariant and temporal gauges. It is noted that the structure of the scattering kernel possesses important qualitative difference from the corresponding one in the Abelian plasma, in spite of the fact that we focused our study on the colorless soft excitations. It is shown that four-plasmon decay is suppressed by the power of $g$ relative to the process of nonlinear scattering of plasmons by thermal particles at the soft momentum scale. It is stated that the former process becomes important in going to the ultrasoft region of the momentum scale.Comment: 41, LaTeX, minor changes, identical to published versio