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In this work, the interaction potential between an atom (with definite Static Polarizability) and a perfect neutral conductive wall is evaluated in two approaches. First, using, the explicit form of the singlet and doublet parts of the vacuum vector potential operator in atomic quadratic stark shift formula and taking the expectation value in vacuum state. Second, writing, the quadratic stark shift formula in terms of electric field correlation function, relating the correlation function to the imaginary parts of the vector potential Green function tensor components (via fluctuation dissipation theorem in statistical mechanics) and the evaluation of the required vector potential Green function tensor components. The consistency of the two methods is shown. [ABSTRACT FROM AUTHOR]

This paper presents an approach to estimating the 2.1D sketch from monocular, low-level visual cues. We use a low-level segmenter to partition the image into regions, and, then, estimate their 2.1D sketch, subject to figure-ground and similarity constraints between neighboring regions. The 2.1D sketch assigns a depth ordering to image regions which are expected to correspond to objects and surfaces in the scene. This is cast as a constrained convex optimization problem, and solved within the optimization transfer framework. The optimization objective takes into account the curvature and convexity of parts of region boundaries, appearance, and spatial layout properties of regions. Our new optimization transfer algorithm admits a closed-form expression of the duality gap, and thus allows explicit computation of the achieved accuracy. The algorithm is efficient with quadratic complexity in the number of constraints between image regions. Quantitative and qualitative results on challenging, real-world images of Berkeley segmentation, Geometric Context, and Stanford Make3D datasets demonstrate our high accuracy, efficiency, and robustness. [ABSTRACT FROM AUTHOR]

We present the results of our study of the electrooptic properties of a one-dimensional photonic crystal created from alternating thin layers of two organic compounds, a ferroelectric and a dye. We show that the ferroelectric subsystem of molecular layers in such a heterostructure can be polarized by an external electric field, leading to a linear electrooptic effect and bistability of the electrooptic response in the spectral region of the photonic stop band. On the other hand, a quasi-linear electrooptic effect attributable to the quadratic Stark effect and the built-in spatially periodic static electric field is observed in the spectral region of the absorption of dye molecules. The emergence of this built-in field is explained in terms of the continuity of the electric displacement vector in a spatially periodic dielectric heterostructure with a macroscopically polarized subsystem of ferroelectric layers. [ABSTRACT FROM AUTHOR]

Current trends in laser technology have reached the regime of studying atoms stabilized against ionization, going beyond the perturbation theory. In this work, properties of a laser-dressed sulfur atom are examined in this stabilization regime. The electronic structure of a sulfur atom changes dramatically as it interacts with strong high-frequency laser fields. Degenerate molecularlike states are obtained for the ground state triplet of the laser-dressed sulfur atom for high-frequency and moderate intensity laser parameters. The degenerate ground state is obtained for a laser intensity which is smaller by more than one order of magnitude than the intensity required for hydrogen atoms due to many electron screening effects. An infinitesimally weak static field mixes these degenerate states to give rise to asymmetric states with large permanent dipole moments. Hence, a strong linear Stark effect rather than the usual quadratic one is obtained. [ABSTRACT FROM AUTHOR]

Hydrogen and deuterium Rydberg atoms, initially moving at velocities of 600 and 560 m s-1, respectively, in pulsed supersonic beams, have been decelerated and electrostatically trapped following adiabatic 90? deflection from their initial axis of propagation to minimize collisions with the trailing edge of the gas pulses. The time evolution of the potential energy surfaces, over which the atoms undergoing deceleration travel during the trap-loading process, is analogous to that of a moving electrodynamic trap. It has been studied in the laboratory-fixed frame of reference and in the continuously moving frame of reference defined by the instantaneous position of the electric-field minimum around which the atoms are located. The importance of the quadratic Stark effect in the deceleration of samples in Rydberg states with principal quantum numbers above 35 has also been investigated by comparison of experimental results with predictions resulting from the numerical calculation of particle trajectories. The data presented for deuterium atoms represent the first application of Rydberg-Stark deceleration and trapping for this atom. Comparison of the rate of loss of n = 30 H and D atoms from the trap enables one to conclude that it is not affected by the particle dynamics during deceleration and trap loading. [ABSTRACT FROM AUTHOR]

Abstract: Origins of absorption shifts in polar liquids are considered for centrosymmetric chromophores devoid of dipole moments. The refractive index (n) dependent bathochromism shows that the excited state is always more polarizable than ground state. With increasing solvent dielectric constant (ɛ), mainly red shifts occur, but there are exceptions. Hypsochromism of n–π* transition in s-tetrazine is ascribed to a decrease of quadrupole moment in the excited state. In this case the upper level is pushed up in the reaction field of the ground-state quadrupole. Red shifts of intense bands in polyenes (11Bu or S2) and polyarenes (1Bb or β), reaching ∼−250cm−1 are assigned to local polarization in the reaction fields of chromophore bond dipoles. The hyperbolic-like ɛ-dependence of solvent shift, approximated to an empirical function (ɛ − n 2)/(ɛ − n 2 + c), is much steeper (with “stretching” factor c =3±0.5) in this case, as compared to that for the linear effect (for s-tetrazine, c =9). Polarization mechanism also causes less band broadening in polar environments. Contrary to a common view, the spectral shift is probing local reaction fields of chromophores, rather than random fields in the cavities accommodating the dye. Negligible polarization in solvent “cavity” fields is in accordance with earlier hole-burning study of matrix induced dipole moments in tetrapyrrolic pigments that depend surprisingly little on the polarity of polymeric hosts (R.B. Altmann, I. Renge, L. Kador, D. Haarer, J. Chem. Phys. 97 (1992) 5316 ). [Copyright &y& Elsevier]

Abstract: Most biological functions of carotenoids relate to strong visible absorption. In a quest to protein matrix effects on spectra, the shifts produced by solvent refractive index (n) and static dielectric permittivity (ɛ) were quantified for visible absorption maxima of β-carotene and a model compound with sharper bands, tetra-tert-butylnonaene ttbP9. The dispersive red shift that depends on optical dielectric constant n 2 is insensitive to polarity, in disagreement with previous work (H. Nagae, et al., J. Chem. Phys. 101 (1994) 6750). Small residual red shift in polar liquids obtained after subtraction of the dispersive component, obeys a static susceptibility function (ɛ − n 2)/(ɛ − n 2 +4). Because polyenes show little inhomogeneous band broadening in polar solvents, the shift was assigned mainly to quadratic Stark effect, rather than to a reaction field of quadrupolar origin, proposed earlier (N. Ghoneim, P. Suppan, Spectrochim. Acta A, 51 (1995) 1043). It is highly plausible that the chromophore is polarized in short-range “edge fields”, according to molecular dynamics/semiempirical simulations (F. Cichos, et al., J. Chem. Phys. 114 (2001) 6824), not in a uniform cavity field, as usually presumed. [Copyright &y& Elsevier]

A new formalism has been elaborated for calculations of hydrogen line profiles emitted by dense plasmas. The main equation of this formalism has a similar form to a set of close-coupled, time-dependent partial differential equations. Calculated line shapes are broadened, shifted and asymmetrical. The formalism yields both shifts and widths of a line calculated within the same theoretical approach. A new basis of the appropriate subspace of the Hilbert space has been built. This basis gives an accurate description of the quadratic Stark effect, and the interaction of the emitter with field gradients. The computer simulation has been used to determine the emitter perturbations by electrons and ions. Calculations were performed for the Balmer alpha line, because this line is a very helpful tool for a dense plasma diagnostic and there is a great interest in the shape of the line. Final results have been compared with experimental and theoretical findings of other authors. [Copyright &y& Elsevier]