Jansenpritchard5738

Benchmark results show excellent agreement with theoretical predictions, showcasing the remarkable long-time accuracy of the proposed algorithm.The general set of nonlocal M-component nonlinear Schrödinger (nonlocal M-NLS) equations obeying the PT-symmetry and featuring focusing, defocusing, and mixed (focusing-defocusing) nonlinearities that has applications in nonlinear optics settings, is considered. First, the multisoliton solutions of this set of nonlocal M-NLS equations in the presence and in the absence of a background, particularly a periodic line wave background, are constructed. Then, we study the intriguing soliton collision dynamics as well as the interesting positon solutions on zero background and on a periodic line wave background. In particular, we reveal the fascinating shape-changing collision behavior similar to that of in the Manakov system but with fewer soliton parameters in the present setting. The standard elastic soliton collision also occurs for particular parameter choices. More interestingly, we show the possibility of such elastic soliton collisions even for defocusing nonlinearities. Furthermore, for the nonlocal M-NLS equations, the dependence of the collision characteristics on the speed of the solitons is analyzed. In the presence of a periodic line wave background, we notice that the soliton amplitude can be enhanced significantly, even for infinitesimal amplitude of the periodic line waves. In addition to these solutions, by considering the long-wavelength limit of the obtained soliton solutions with proper parameter constraints, higher-order positon solutions of the nonlocal M-NLS equations are derived. The background of periodic line waves also influences the wave profiles and amplitudes of the positons. Specifically, the positon amplitude can not only be enhanced but also be suppressed on the periodic line wave background of infinitesimal amplitude.We compare the convergence of several flat-histogram methods applied to the two-dimensional Ising model, including the recently introduced stochastic approximation with a dynamic update factor (SAD) method. read more We compare this method to the Wang-Landau (WL) method, the 1/t variant of the WL method, and standard stochastic approximation Monte Carlo (SAMC). In addition, we consider a procedure WL followed by a "production run" with fixed weights that refines the estimation of the entropy. We find that WL followed by a production run does converge to the true density of states, in contrast to pure WL. Three of the methods converge robustly SAD, 1/t-WL, and WL followed by a production run. Of these, SAD does not require a priori knowledge of the energy range. This work also shows that WL followed by a production run performs superior to other forms of WL while ensuring both ergodicity and detailed balance.Smectic liquid crystals with a layering order of rodlike molecules can be drawn in the form of free standing films across holes. Extensive experimental studies have shown that smectic-C (SmC) liquid crystals (LCs) with tilted molecules form periodic stripes in the thinner parts of the meniscus, which persist over a range of temperatures above the transition of the bulk medium to the SmA phase in which the tilt angle is zero. The prevailing theoretical models cannot account for all the experimental observations. We propose a model in which we argue that the negative curvature of the surface of the meniscus results in an energy cost when the molecules tilt at the surface. The energy can be reduced by exploiting the allowed (∇·k)(∇·c) deformation which couples the divergence of k, the unit vector along the layer normal, with that of c, the projection of the tilted molecular director on the layer plane. We propose a structure with periodic bending of layers with opposite curvatures, in which the c-vector field itself has a continuous deformation. Calculations based on the theoretical model can qualitatively account for all the experimental observations. It is suggested that detailed measurements on the stripes may be useful for getting good estimates of a few curvature elastic constants of SmC LCs.We succeeded in simultaneously cloaking and concentrating direct current in a conducting material through topology optimization based on a level-set method. To design structures that perform these functions simultaneously, optimal topology is explored for improving two objective functions that govern separately the cloaking and concentration of current. Our design scheme, i.e., the topology optimization of a direct-current electric cloak concentrator, provides this bifunctionality well despite simple, common bulk materials being used to make up the structures. The materials also rigorously obey the electric conduction equation in contrast to the approximated artificial materials, so-called metamaterials, of other design schemes. The structural features needed for this simultaneous bifunctionality are found by adopting level-set method to generate material domains and clear structural interfaces. Furthermore, robust performances of the bifunctional structures against fluctuations in electrical conductivity was achieved by improving the fitness incorporating multiple objective functions. Additionally, the influence of the size of the current-concentrating domain on the performances of the optimal configuration is investigated.How can we develop simple yet realistic models of the small neural circuits known as central pattern generators (CPGs), which contribute to generate complex multiphase locomotion in living animals? In this paper we introduce a new model (with design criteria) of a generalized half-center oscillator, (pools of) neurons reciprocally coupled by fast/slow inhibitory and excitatory synapses, to produce either alternating bursting or other rhythmic patterns, characterized by different phase lags, depending on the sensory or other external input. We also show how to calibrate its parameters, based on both physiological and functional criteria and on bifurcation analysis. This model accounts for short-term neuromodulation in a biophysically plausible way and is a building block to develop more realistic and functionally accurate CPG models. Examples and counterexamples are used to point out the generality and effectiveness of our design approach.