Inequalities for Purity Parameters of Multiqudit and Single-Qudit States

We analyze the recently found inequality for eigenvalues of the density matrix and purity parameters describing either a bipartite-system state or a single-qudit state. We rewrite the Minkowski-type trace inequality for the density matrices of the qudit states in terms of the purity parameters and discuss the properties of the inequality obtained, paying special attention to the X-states of two qubits and a single qudit. Also we study the relation of the purity inequalities obtained with the entanglement.     

Optical Resonant Saturation of Dipole–Dipole Broadened Transitions in High-Density Atomic Vapor

Journal of Russian Laser Research - We discuss the experimental research of an optical resonant saturation of a dipole–dipole-broadened atomic transition in the high-density rubidium vapor....     

LES of oxy-fuel jet flames using the Eulerian Stochastic Fields method with differential diffusion

The Eulerian Stochastic Fields (ESF) Monte Carlo method to solve the transported PDF (TPDF) equation is extended to account for differential diffusion effects by incorporating species individual molecular diffusivities. The method has been applied in Large Eddy simulation (LES) to non-piloted oxy-fuel jet flames at different Reynolds numbers experimentally investigated by Sevault et al. [1]. Due to the high H₂ content in the fuel stream and CO₂ in the oxidizer these flames pose new challenges to combustion modeling as the flame structures are different compared to CH₄/air flames. The simulations show very good agreement with the experiments in terms of mixture fraction conditional mean values for temperature and mayor species on the fuel lean side and the reaction zone, deviations on the fuel rich side are discussed. The trend and location of localized extinction is reproduced well in the simulations, as well as differential diffusion effects in the near field. Additionally, it is shown that a neglect of differential diffusion in the combustion model leads to a lifted flame.     

First-order transitions in spherical models: Finite-size scaling

Finite-size behavior near the first-order phase boundary of ferromagnetic spherical models is investigated for block- and cylinder-shaped systems ind dimensions. The bulk thermodynamic singularities are rounded and, asymptotically for large size, obey appropriate scaling laws. Both short-range interactions and long-range couplings, decaying like 1/r^d+ with >0, are analyzed: the short-range results agree precisely with a recently developed scaling theory forO(n) symmetric systems in the limitn. More generally, the scaling functions are universal, depending only on . Explicit aspects of the shape and interactions enter only in the spin wave or Goldstone mode contributions which appear, technically, as corrections to scaling. An appendix analyzes the truncation error in the approximation, by many-fold sums, of multivariate integrals with integrands diverging like [_ja_{j j} ² ]^- as 0.     

On the enhancement of the figure of merit in bulk nanocomposites

In this paper we make a detailed comparison of the thermoelectric properties of quantum dot superlattices with those of equivalently doped bulk material and show that a major contribution to the enhancement of the figure of merit comes from the increase of the thermoelectric power over that of bulk, in addition to the lattice thermal conductivity reduction in quantum dot superlattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Improved Lower Bounds for the Critical Probability of Oriented Bond Percolation in Two Dimensions

We present a coupled decreasing sequence of random walks on Z that dominate the edge process of oriented bond percolation in two dimensions. Using the concept of random walk in a strip, we describe an algorithm that generates an increasing sequence of lower bounds that converges to the critical probability of oriented percolation p_c. From the 7th term on, these lower bounds improve upon 0.6298, the best rigorous lower bound at present, establishing 0.63328 as a rigorous lower bound for p_c. Finally, a Monte Carlo simulation technique is presented; the use thereof establishes 0.64450 as a non-rigorous five-digit-precision (lower) estimate for p_c. Mathematics Subject Classification (1991): 60K35 Supported by CNPq (grant N.301637/91-1). Supported by a grant from CNPq.     

Wigner function and Bell’s inequalities for even and odd coherent states

The Wigner function and the symplectic tomogram of an entangled quantum state, which is a superposition of the photon’s coherent states (even and odd coherent states), is studied. Photon statistics and violation of Bell’s inequality for the photon state are discussed.     

Detection of Single Quantum Dots in Model Systems with Sheet Illumination Microscopy

Single molecule detection and tracking provides at times the only possible method to observe the interactions of low numbers of biomolecules, inlcuding DNA, receptors and signal mediating proteins in living systems. However, most existing imaging methods do not enable both high sensitivity and non-invasive imaging of large specimens. In this study we report a new setup for selective plane illumination microscopy (SPIM), which enables fast imaging and single molecule tracking with the resolution of confocal microscopy and the optical penetration beyond 300 μm. We detect and report our instrumental figures of merit, control values of fluorescence properties of single nano crystals in comparison to both standard widefield configurations, and also values of nanocrystals in multicellular “fruiting bodies” of Dictyostelium, an excellent control as a model developmental system. In the Dictyostelium , we also report some of our first tracking of single nanocrystals with SPIM. The new SPIM setup represents a new technique, which enables fast single molecule imaging and tracking in living systems.