12,309 research outputs found

    Integrable nonlinear field equations and loop algebra structures

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    We apply the (direct and inverse) prolongation method to a couple of nonlinear Schr{\"o}dinger equations. These are taken as a laboratory field model for analyzing the existence of a connection between the integrability property and loop algebras. Exploiting a realization of the Kac-Moody type of the incomplete prolongation algebra associated with the system under consideration, we develop a procedure with allows us to generate a new class of integrable nonlinear field equations containing the original ones as a special case.Comment: 13 pages, latex, no figures

    A Semiotic Analysis on the Perceived Meanings of Coca Cola “Anthem” Video Commercial

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    This study observes the perceived meanings produced by young adult (18 to 30 years old) and older (50 to 65 years old) respondents as respondents from different age group can produce different perceived meanings from each other. The writer's finding is that in perceiving, young adult respondents tend to emphasize on Coca Cola's emotional roles. On the other hand, the older respondents emphasize on Coca Cola's physical roles

    Experimental Verification of a Depth Controller using Model Predictive Control with Constraints onboard a Thruster Actuated AUV

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    In this work a depth and pitch controller for an autonomous underwater vehicle (AUV) is developed. This controller uses the model predictive control method to manoeuvre the vehicle whilst operating within the defined constraints of the AUV actuators. Experimental results are given for the AUV performing a step change in depth whilst maintaining zero pitch

    Quantum coherent transport in a three-arm beam splitter and a Braess paradox

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    The Braess paradox encountered in classical networks is a counterintuitive phenomenon when the flow in a road network can be impeded by adding a new road or, more generally, the overall net performance can degrade after addition of an extra available choice. In this work, we discuss the possibility of a similar effect in a phase-coherent quantum transport and demonstrate it by example of a simple Y-shaped metallic fork. To reveal the Braess-like partial suppression of the charge flow in such device, it is proposed to transfer two outgoing arms into a superconducting state. We show that the differential conductance-vs-voltage spectrum of the hybrid fork structure varies considerably when the extra link between the two superconducting leads is added and it can serve as an indicator of quantum correlations which manifest themselves in the quantum Braess paradox.Comment: 9 pages, 3 figures, the author version presented at the Quantum 2017 Workshop (Torino, Italy, 7-13 May 2017) and submitted to the International Journal of Quantum Information; v2: reference 9 added and the introduction extende

    Femtosecond frequency comb measurement of absolute frequencies and hyperfine coupling constants in cesium vapor

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    We report measurements of absolute transition frequencies and hyperfine coupling constants for the 8S_{1/2}, 9S_{1/2}, 7D_{3/2}, and 7D_{5/2} states in ^{133}Cs vapor. The stepwise excitation through either the 6P_{1/2} or 6P_{3/2} intermediate state is performed directly with broadband laser light from a stabilized femtosecond laser optical-frequency comb. The laser beam is split, counter-propagated and focused into a room-temperature Cs vapor cell. The repetition rate of the frequency comb is scanned and we detect the fluorescence on the 7P_{1/2,3/2} -> 6S_{1/2} branches of the decay of the excited states. The excitations to the different states are isolated by the introduction of narrow-bandwidth interference filters in the laser beam paths. Using a nonlinear least-squares method we find measurements of transition frequencies and hyperfine coupling constants that are in agreement with other recent measurements for the 8S state and provide improvement by two orders of magnitude over previously published results for the 9S and 7D states.Comment: 14 pages, 14 figure

    DigiPrim – The state of digitalization at primary school level. Short version.

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