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Permanent URI for this collectionhttps://acikarsiv.thk.edu.tr/handle/123456789/2550
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Publication Absorption enhancement of molecules in the weak plasmon–exciton coupling regime(The Optical Society, 2014-08-18) Sinan Balci; Ertugrul Karademir; Coskun Kocabas; Atilla AydinliPublication Hopf bifurcation in an overlapping generations resource economy with endogenous population growth rate(Walter de Gruyter GmbH, 2016-01-01) Burcu Fazlıoğlu; Hüseyin Çağrı Sağlam; Mustafa Kerem YükselAbstractAs scarce environmental resources necessarily put a constraint on population growth, we use more realistic population growth dynamics which contemplates a feedback mechanism between population growth rate and resource availability. We examine the local stability properties in overlapping generations resource economies which takes this feedback mechanism into account. The results indicate that Hopf bifurcation may arise without requiring logistic regeneration or unconventional constraints on parameter values. In particular, Hopf bifurcation is encountered under convex-concave dependence of carrying capacity on the resource availability.Publication Energy Stable Model Order Reduction for the Allen-Cahn Equation(Springer International Publishing, 2017) Murat Uzunca; Bülent KarasözenPublication Kerr-Schild–Kundt metrics are universal(IOP Publishing, 2017-03-13) Metin Gürses; Tahsin Çağrı Şişm; Bayram TekinPublication Energy Stable Interior Penalty Discontinuous Galerkin Finite Element Method for Cahn–Hilliard Equation(Walter de Gruyter GmbH, 2017-07-14) Ayşe Sarıaydın-Filibelioğlu; Bülent Karasözen; Murat UzuncaAbstract An energy stable conservative method is developed for the Cahn–Hilliard (CH) equation with the degenerate mobility. The CH equation is discretized in space with the mass conserving symmetric interior penalty discontinuous Galerkin (SIPG) method. The resulting semi-discrete nonlinear system of ordinary differential equations are solved in time by the unconditionally energy stable average vector field (AVF) method. We prove that the AVF method preserves the energy decreasing property of the fully discretized CH equation. Numerical results for the quartic double-well and the logarithmic potential functions with constant and degenerate mobility confirm the theoretical convergence rates, accuracy and the performance of the proposed approach.Publication Energy Stable Discontinuous Galerkin Finite Element Method for the Allen–Cahn Equation(World Scientific Pub Co Pte Lt, 2018-04-25) Bülent Karasözen; Murat Uzunca; Ayşe Sariaydin-Fi̇li̇beli̇oğlu; Hamdullah YücelIn this paper, we investigate numerical solution of Allen–Cahn equation with constant and degenerate mobility, and with polynomial and logarithmic energy functionals. We discretize the model equation by symmetric interior penalty Galerkin (SIPG) method in space, and by average vector field (AVF) method in time. We show that the energy stable AVF method as the time integrator for gradient systems like the Allen–Cahn equation satisfies the energy decreasing property for fully discrete scheme. Numerical results reveal that the discrete energy decreases monotonically, the phase separation and metastability phenomena can be observed, and the ripening time is detected correctly.Publication Note on soft photons and Faddeev–Jackiw symplectic reduction of quantum electrodynamics in the eikonal limit(World Scientific Pub Co Pte Lt, 2018-09-10) Suat DengizIn this note, we go over the recent soft photon model and Faddeev–Jackiw quantization of the massless quantum electrodynamics in the eikonal limit to some extent. Throughout our readdressing, we observe that the gauge potentials in both approaches become pure gauges and the associated eikonal Faddeev–Jackiw quantum bracket matches with the soft quantum bracket. These observations and the fact that the gauge fields in two cases localize in two-dimensional plane (even if it is spatial in soft photon case and (1[Formula: see text]+[Formula: see text]1)-dimensional Minkowski in the eikonal case) imply that there might be an interesting relation between these two distinct perspectives.Publication A Modified Gravity Theory: Null Aether(IOP Publishing, 2019-03) Metin Gürses; Çetin Şentürk; Şentürk, Çetin