Correlations in atomic systems: Diagnosing coherent superpositions

While investigating quantum correlations in atomic systems, we note that single measurements contain information about these correlations. Using a simple model of measurement -- analogous to the one used in quantum optics -- we show how to extract higher order correlation functions from individual "phtotographs" of the atomic sample. As a possible application we apply the method to detect a subtle phase coherence in mesoscopic superpostitions.Comment: 4 pages, 2 figures, provisionally accepted to Physical Review Letter

hp-HGS strategy for inverse 3D DC resistivity logging measurement simulations

In this paper we present a twin adaptive strategy hp-HGS for solving inverse problems related to 3D DC borehole resistivity measurement simulations. The term "simulation of measurements" is widely used by the geophysical community. A quantity of interest, voltage, is measured at a receiver electrode located in the logging instrument. We use the self-adaptive goal-oriented hp-Finite Element Method (hp-FEM) computer simulations of the process of measurements in deviated wells (when the angle between the borehole and formation layers are < 90 deg). We also employ the hierarchical genetic search (HGS) algorithm to solve the inverse problem. Each individual in the population represents a single configuration of the formation layers. The evaluation of the individual is performed by solving the direct problem by means of the hp-FEM algorithm and by comparison with measured logging curve. We conclude the paper with some discussion on the parallelization of the algorithm. © 2012 Published by Elsevier Ltd

A hybrid method for inversion of 3D DC resistivity logging measurements

This paper focuses on the application of hp hierarchic genetic strategy (hp-HGS) for solution of a challenging problem, the inversion of 3D direct current (DC) resistivity logging measurements. The problem under consideration has been formulated as the global optimization one, for which the objective function (misfit between computed and reference data) exhibits multiple minima. In this paper, we consider the extension of the hp-HGS strategy, namely we couple the hp-HGS algorithm with a gradient based optimization method for a local search. Forward simulations are performed with a self-adaptive hp finite element method, hp-FEM. The computational cost of misfit evaluation by hp-FEM depends strongly on the assumed accuracy. This accuracy is adapted to the tree of populations generated by the hp-HGS algorithm, which makes the global phase significantly cheaper. Moreover, tree structure of demes as well as branch reduction and conditional sprouting mechanism reduces the number of expensive local searches up to the number of minima to be recognized. The common (direct and inverse) accuracy control, crucial for the hp-HGS efficiency, has been motivated by precise mathematical considerations. Numerical results demonstrate the suitability of the proposed method for the inversion of 3D DC resistivity logging measurements

Multi-objective hierarchic memetic solver for inverse parametric problems

We propose a multi-objective approach for solving challenging inverse parametric problems. The objectives are misfits for several physical descriptions of a phenomenon under consideration, whereas their domain is a common set of admissible parameters. The resulting Pareto set, or parameters close to it, constitute various alternatives of minimizing individual misfits. A special type of selection applied to the memetic solution of the multi-objective problem narrows the set of alternatives to the ones that are sufficiently coherent. The proposed strategy is exemplified by solving a real-world engineering problem consisting of the magnetotelluric measurement inversion that leads to identification of oil deposits located about 3 km under the Earth's surface, where two misfit functions are related to distinct frequencies of the electric and magnetic waves

A multi-objective memetic inverse solver reinforced by local optimization methods

We propose a new memetic strategy that can solve the multi-physics, complex inverse problems, formulated as the multi-objective optimization ones, in which objectives are misfits between the measured and simulated states of various governing processes. The multi-deme structure of the strategy allows for both, intensive, relatively cheap exploration with a moderate accuracy and more accurate search many regions of Pareto set in parallel. The special type of selection operator prefers the coherent alternative solutions, eliminating artifacts appearing in the particular processes. The additional accuracy increment is obtained by the parallel convex searches applied to the local scalarizations of the misfit vector. The strategy is dedicated for solving ill-conditioned problems, for which inverting the single physical process can lead to the ambiguous results. The skill of the selection in artifact elimination is shown on the benchmark problem, while the whole strategy was applied for identification of oil deposits, where the misfits are related to various frequencies of the magnetic and electric waves of the magnetotelluric measurement

A characterization of quadratic-multiplicative mappings

In the spirit of some earlier studies of Jean Dhombres, Roman Ger and Ludwig Reich we discuss the alienation problem for quadratic and multiplicative mappings

Biomechanical properties of the thin PVD coatings defined by red blood cells

The measurement of the strength of bonds between biomaterials and cells is a major challenge in biotribology since it allows for the identification of different species in adhesion phenomena. Biomaterials, such as diamond-like carbon (DLC), titanium, and titanium nitride, seem to be good candidates for future blood-contact applications. These materials were deposited as thin films by the hybrid pulsed laser deposition (PLD) technique to examine the influence of such surfaces on cell behavior. The biomaterial examinations were performed in static conditions with red blood cells and then subjected to a dynamical test to observe the cell detachment kinetics. The tests revealed differences in behavior with respect to the applied coating material. The strongest cell-biomaterial interaction was observed for the carbonbased materials compared to the titanium and titanium nitride. Among many tests, a radial flow interaction analysis gives the opportunity to analyze cell adhesion to the applied material with the high accuracy. Analysis of concentrates helped to select materials for further dynamic tests on blood using an aortic flow simulator. In this case, the platelet adhesion to the surface and their degree of activation was analyzed. The quality of the selected coating was tested using a scratch test. The analyses of the microstructure were done using high resolution transmission electron microscopy. The phase composition and the residual stress were analyzed using X-ray diffraction methods

Chemical composition of atherosclerotic plaques of apoE/LDLR-double knockout mice by synchrotron radiation FTIR microspectroscopy

Atherosclerosis is a multietiological inflammatory disease of large and medium-sized arteries of increasing incidence in westernized countries. The aim of this study was to identify the biochemical changes during the progression of atherosclerosis by synchrotron radiation Fourier transform infrared microspectroscopy in atheromas of apoE/$LDLR^{-//-}$ mice fed egg-rich diet supplemented or not with angiotensin converting enzyme inhibitor perindopril. Synchrotron radiation Fourier transform infrared microspectroscopy technique was used to obtain information at high spatial resolution about the distribution of proteins (C-N, N-H, CO for amide I and amide II bands), lipids ($CH_2$, $CH_3$ bands) as well as mineral deposits (calcium carbonates and phosphates). Total contents of lipids and proteins were found to be significantly lower in animals treated with the diet and perindopril. An increase in saturation level of lipids was observed in animals fed with egg-rich diet when compared to the normal diet and perindopril treatment, which did not inhibit this effect. Moreover, a significant change in the secondary structure of proteins (ratio between absorption bands 1634 $cm^{-1}$/1656 $cm^{-1}$ attributed to β-type and α-type, respectively) was observed in both experimental groups in comparison with the control. Principal component analysis was used to analyse the recorded spectra. It has revealed that higher content of phosphates (wavenumber range 950-1020 $cm^{-1}$) was observed between egg-rich diet fed animals and the control group