12,309 research outputs found
Integrable nonlinear field equations and loop algebra structures
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
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
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
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
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
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