Theoretical study of loss compensation in long-range dielectric loaded surface plasmon polariton waveguides

In this paper, a theoretical study of loss compensation in long-range dielectric loaded surface plasmon waveguides (LR-DLSPPs) is presented. Although extendable to other gain materials, rare-earth doped double tungstates are used as gain material in this work. Two different structures are studied and the effect of the different waveguide geometrical parameters on the material gain required to fully compensate the propagation losses are reported. The simulations were performed at 1.55 micrometer wavelength. A material gain as low as 12.5 dB/cm was determined as sufficient to obtain complete loss compensation in one of the proposed waveguide structures supporting sub-micron lateral mode dimension

Guaranteed Convergence of a Regularized Kohn-Sham Iteration in Finite Dimensions

The exact Kohn-Sham iteration of generalized density-functional theory in finite dimensions witha Moreau-Yosida regularized universal Lieb functional and an adaptive damping step is shown toconverge to the correct ground-state density.Comment: 3 figures, contains erratum with additional author Paul E. Lammer

Asymptotically free four-fermion interactions and electroweak symmetry breaking

We investigate the fermions of the standard model without a Higgs scalar. Instead, we consider a non-local four-quark interaction in the tensor channel which is characterized by a single dimensionless coupling $f$. Quantization leads to a consistent perturbative expansion for small $f$. The running of $f$ is asymptotically free and therefore induces a non-perturbative scale $\Lambda_{ch}$, in analogy to the strong interactions. We argue that spontaneous electroweak symmetry breaking is triggered at a scale where $f$ grows large and find the top quark mass of the order of $\Lambda_{ch}$. We also present a first estimate of the effective Yukawa coupling of a composite Higgs scalar to the top quark, as well as the associated mass ratio between the top quark and the W boson.Comment: 24 page

Conserved Density Fluctuation and Temporal Correlation Function in HTL Perturbation Theory

Considering recently developed Hard Thermal Loop perturbation theory that takes into account the effect of the variation of the external field through the fluctuations of a conserved quantity we calculate the temporal component of the Euclidian correlation function in the vector channel. The results are found to be in good agreement with the very recent results obtained within the quenched approximation of QCD and small values of the quark mass ($\sim 0.1T$) on improved lattices of size $128^3\times N_\tau$ at ($N_\tau=40, \ T=1.2T_C$), ($N_\tau=48, \ T=1.45T_C$), and ($N_\tau=16, \ T=2.98T_C$), where $N_\tau$ is the temporal extent of the lattice. This suggests that the results from lattice QCD and Hard Thermal Loop perturbation theory are in close proximity for a quantity associated with the conserved density fluctuation.Comment: 16 pages, 4 figures; One para added in introduction, Fig 1 modified; Accepted in Phys. Rev.

The levels problem in psychopathology

Psychiatric disorders are studied at multiple levels, but there is no agreement on how these levels are related to each other, or how they should be understood in the first place. In this paper, I provide an account of levels and their relationships that is suited for psychopathology, drawing from recent debates in philosophy of science. Instead of metaphysical issues, the focus is on delivering an understanding of levels that is relevant and useful for scientific practice. I also defend a pragmatic approach to the question of reduction, arguing that even in-principle reductionists should embrace pluralism in practice. Finally, I discuss the benefits and challenges in integrating explanations and models of different levels

Bundled Discounts: The Ninth Circuit and the Third Circuit are on Separate LePage\u27s

Most courts and commentators agree that the ultimate goal of antitrust is efficiency. Accordingly, an antitrust aim is to guarantee competitive markets, which both increases output and lowers prices to the benefit of consumers. Bundled discounts, packages of goods put together by a seller that are sold at a lower price than if each good were purchased separately, may provide a means of enhancing competition. Such bundles are prevalent in nearly every market including fast food value meals, season tickets to sporting events, and buy one, get one half-price schemes. Sellers provide bundled discounts for a variety of reasons including the reduction of transaction costs, engendering customer loyalty, or sometimes in response to pressure from large, diversified buyers. These discounts often result in increased output and decreased prices, which are consumer welfare increasing outcomes. However, it is possible for a seller who has multiple products to use bundled discounts to exclude an efficient competitor who only sells one product. This exclusionary conduct is exactly what antitrust laws are meant to discourage. However, because bundled discounts are so pervasive and are often procompetitive, any liability rules governing their legality should be narrowly drawn to avoid chilling such a desirable practice. In 2003, the Third Circuit decided a case, LePage\u27s, Inc. v. 3M, involving a plaintiff that claimed the defendant\u27s bundled discount was exclusionary. The Third Circuit held the bundling practices of office supply manufacturer 3M to be in violation of antitrust laws. However, in doing so, the court failed to set an effective standard to evaluate the anticompetitive nature of bundled discounts. In a recent decision, Cascade Health Solutions v. PeaceHealth, the Ninth Circuit strayed from the approach set forth in the LePage\u27s decision and set a cost-based standard to be used in the analysis of bundled discounts. While the standard set in Peacehealth is a positive step in analyzing bundled discounts, the Ninth Circuit may not have reached far enough. Because bundled discounting is typically a procompetitive practice, the court should fashion as narrow a rule as possible. It is possible to theorize a situation where, under the Ninth Circuit\u27s standard, a competitor could bring a successful lawsuit against a bundled discounter even though the competitor could offer an equally competitive bundle if it collaborated with another firm. Therefore, the standard set forth by the Ninth Circuit falls short by ignoring the possibility of rival competitors collaborating to compete with a bundled discounter

Psychopathology and Truth:A Defense of Realism

Recently Kenneth Kendler and Peter Zachar have raised doubts about the correspondence theory of truth and scientific realism in psychopathology. They argue that coherentist or pragmatist approaches to truth are better suited for understanding the reality of psychiatric disorders. In this article, I show that rejecting realism based on the correspondence theory is deeply problematic: It makes psychopathology categorically different from other sciences, and results in an implausible view of scientific discovery and progress. As an alternative, I suggest a robustness-based approach that can accommodate the significance of coherence and pragmatic factors without rejecting scientific realism and the correspondence theory of truth

Kohn-Sham theory with paramagnetic currents: compatibility and functional differentiability

Recent work has established Moreau-Yosida regularization as a mathematical tool to achieve rigorous functional differentiability in density-functional theory. In this article, we extend this tool to paramagnetic current-density-functional theory, the most common density-functional framework for magnetic field effects. The extension includes a well-defined Kohn-Sham iteration scheme with a partial convergence result. To this end, we rely on a formulation of Moreau-Yosida regularization for reflexive and strictly convex function spaces. The optimal $L^p$-characterization of the paramagnetic current density $L^1\cap L^{3/2}$ is derived from the $N$-representability conditions. A crucial prerequisite for the convex formulation of paramagnetic current-density-functional theory, termed compatibility between function spaces for the particle density and the current density, is pointed out and analyzed. Several results about compatible function spaces are given, including their recursive construction. The regularized, exact functionals are calculated numerically for a Kohn-Sham iteration on a quantum ring, illustrating their performance for different regularization parameters