A new lattice measurement for potentials between static SU(3) sources

In this article, a new calculation of static potentials between sources of different representations in SU(3) gauge group is presented. The results of author's previous study \cite{Deld00} at the smallest lattice spacing $a_{s}\simeq0.11$~ fm are shown to have been affected by finite volume effects. Within statistical errors, the new results obtained here are still in agreement with both, Casimir scaling and flux tube counting. There is also no contradiction to the results obtained in Ref.~ \cite{Bali00} which however exclude flux counting.Comment: To be published in EPJ

Interaction between multi components vortices at arbitrary distances using a variational method in the Ginzburg-Landau theory

We study the interaction between the vortices in multi components superconductors based on the Jacobs and Rebbi variation method using Ginzburg-Landau theory. With one condensation, we get attraction interaction between the vortices for type I and repulsion for type II superconductors. With two condensation states such as Mg B_{2} superconductors the behavior is quite different. There is attraction at large distances and repulsion when the vortices are close to each other. A stability point at distance 2.7/{\lambda}_{1} is obtained. In the case of three condensation states such as iron based superconductors,we see different behavior depending on penetration depth and correlation length. The formation energy of a vortex with three condensation states is larger than the one with one condensation state with comparable penetration and correlation length. We obtain two stability points for the superconductors with three condensation states

Confinement and the second vortex of the SU(4) gauge group

We study the potential between static SU(4) sources using the Model of Thick Center Vortices. Such vortices are characterized by the center elements $z_1=\mathrm i$ and $z_2=z_1^2$. Fitting the ratios of string tensions to those obtained in Monte-Carlo calculations of lattice QCD we get $f_2>f_1^2$, where $f_n$ is the probability that a vortex of type $n$ is piercing a plaquette. Because of $z_2=z_1^2$ vortices of type two are overlapping vortices of type one. Therefore, $f_2>f_1^2$ corresponds to the existence of an attractive force between vortices of type one

Short distance potential and the thick center vortex model

The short distance potentials between heavy SU(3) and SU(4) sources are calculated by increasing the role of vortex fluxes piercing Wilson loops with contributions close to the trivial center element and by fluctuating the vortex core size in the model of thick center vortices. By this method, a Coulombic potential consistent with Casimir scaling is obtained. In addition, all other features of the potential including a linear intermediate potential in agreement with Casimir scaling and a large distance potential proportional to the $N$-ality of the representation are restored. Therefore, the model of thick center vortices may be used as a phenomenological model, which is able to describe the potential for all regimes.Comment: 9 pages and 6 figure

Monopoles, vortices and their correlations in SU(3) gauge group

Topological defects such as monopole, vortices and "chains"of the SU(3) gauge group are studied using its SU(2) subgroups. Two appropriate successive gauge transformations are applied to the subgroups to identify the chains of monopoles and vortices. Using the fact that the defects of the subgroups are not independent, the SU(3) defects and the Lagrangian are obtained and compared with the ones provided by Cho decomposition method. By comparing the results with the ones which have been obtained directly for the SU(3) gauge group, the relation and possible interactions between the defects of the subgroups are discussed.Comment: 19 pages, 11 figure

Static SU(3) potentials for sources in various representations

The potentials and string tensions between static sources in a variety of representations (fundamental, 8, 6, 15-antisymmetric, 10, 27 and 15-symmetric) have been computed by measuring Wilson loops in pure gauge SU(3). The simulations have been done primarily on anisotropic lattices, using a tadpole improved action improved to O(a_{s}^4). A range of lattice spacings (0.43 fm, 0.25 fm and 0.11 fm) and volumes ($8^3\times 24$, $10^3 \times 24$, $16^3 \times 24$ and $18^3 \times 24$) has been used in an attempt to control discretization and finite volume effects. At intermediate distances, the results show approximate Casimir scaling. Finite lattice spacing effects dominate systematic error, and are particularly large for the representations with the largest string tensions.Comment: Version to appear in PR

Advanced magneto-optical microscopy: Imaging from picoseconds to centimeters - imaging spin waves and temperature distributions (invited)

© 2016 Author(s).Recent developments in the observation of magnetic domains and domain walls by wide-field optical microscopy based on the magneto-optical Kerr, Faraday, Voigt, and Gradient effect are reviewed. Emphasis is given to the existence of higher order magneto-optical effects for advanced magnetic imaging. Fundamental concepts and advances in methodology are discussed that allow for imaging of magnetic domains on various length and time scales. Time-resolved imaging of electric field induced domain wall rotation is shown. Visualization of magnetization dynamics down to picosecond temporal resolution for the imaging of spin-waves and magneto-optical multi-effect domain imaging techniques for obtaining vectorial information are demonstrated. Beyond conventional domain imaging, the use of a magneto-optical indicator technique for local temperature sensing is shown

Quark Confinement in Restricted SU(2) Gauge Theory

We apply Zwanziger formalism to Cho restricted $SU(2)$ theory to obtain the potential in a static quark-antiquark pair. Cho restricted theory is a self-consistent subset of a non-Abelian $SU(2)$ gauge theory which tries to describe the infrared regime of Yang-Mills gauge theories. In Zwanziger formalism, a local Lagrangian depending on two electric and magnetic gauge fields is constructed for the theories where both electric and magnetic charges exist. Based on this local Lagrangian the propagator and then the potential between quarks is calculated in two limits: $m_{C} r \ll 1$ and $m_{C} r \gg 1$, where $m_{C}$ is the mass of the dual gauge boson and $r$ is the distance between the quark and the antiquark.Comment: 2 Figures, 15 pages, Version accepted for publication in PR

Cortical interaction of bilateral inputs is similar for noxious and innocuous stimuli but leads to different perceptual effects

The cerebral integration of somatosensory inputs from multiple sources is essential to produce adapted behaviors. Previous studies suggest that bilateral somatosensory inputs interact differently depending on stimulus characteristics, including their noxious nature. The aim of this study was to clarify how bilateral inputs evoked by noxious laser stimuli, noxious shocks, and innocuous shocks interact in terms of perception and brain responses. The experiment comprised two conditions (right-hand stimulation and concurrent stimulation of both hands) in which painful laser stimuli, painful shocks and non-painful shocks were delivered. Perception, somatosensory-evoked potentials (P45, N100, P260), laser-evoked potentials (N1, N2 and P2) and event-related spectral perturbations (delta to gamma oscillation power) were compared between conditions and stimulus modalities. The amplitude of negative vertex potentials (N2 or N100) and the power of delta/theta oscillations were increased in the bilateral compared with unilateral condition, regardless of the stimulus type (P < 0.01). However, gamma oscillation power increased for painful and non-painful shocks (P < 0.01), but not for painful laser stimuli (P = 0.08). Despite the similarities in terms of brain activity, bilateral inputs interacted differently for painful stimuli, for which perception remained unchanged, and non-painful stimuli, for which perception increased. This may reflect a ceiling effect for the attentional capture by noxious stimuli and warrants further investigations to examine the regulation of such interactions by bottom–up and top–down processes