Experimentally Attainable Optimal Pulse Shapes Obtained with the Aid of Genetic Algorithms

We propose a methodology to design optimal pulses for achieving quantum optimal control on molecular systems. Our approach constrains pulse shapes to linear combinations of a fixed number of experimentally relevant pulse functions. Quantum optimal control is obtained by maximizing a multi-target fitness function with genetic algorithms. As a first application of the methodology we generated an optimal pulse that successfully maximized the yield on a selected dissociation channel of a diatomic molecule. Our pulse is obtained as a linear combination of linearly chirped pulse functions. Data recorded along the evolution of the genetic algorithm contained important information regarding the interplay between radiative and diabatic processes. We performed a principal component analysis on these data to retrieve the most relevant processes along the optimal path. Our proposed methodology could be useful for performing quantum optimal control on more complex systems by employing a wider variety of pulse shape functions.Comment: 7 pages, 6 figure

Spin-orbit induced chirality of Andreev states in Josephson junctions

We study Josephson junctions (JJs) in which the region between the two superconductors is a multichannel system with Rashba spin-orbit coupling (SOC) where a barrier or a quantum point contact (QPC) is present. These systems might present unconventional Josephson effects such as Josephson currents for zero phase difference or critical currents that \textit{depend on} the current direction. Here, we discuss how the spin polarizing properties of the system in the normal state affect the spin characteristic of the Andreev bound states inside the junction. This results in a strong correlation between the spin of the Andreev states and the direction in which they transport Cooper pairs. While the current-phase relation for the JJ at zero magnetic field is qualitatively unchanged by SOC, in the presence of a weak magnetic field a strongly anisotropic behavior and the mentioned anomalous Josephson effects follow. We show that the situation is not restricted to barriers based on constrictions such as QPCs and should generically arise if in the normal system the direction of the carrier's spin is linked to its direction of motion.Comment: 19 pages, 9 figures. To appear in PR

Faktor-faktor yang Memengaruhi Loyalitas Pengguna Ovo pada Grab

The purpose of the research is to analyze the factors that influence the loyalty of OVO users in Grab. The analytical method used by the author in conducting this research is to use quantitative research as many as 311 respondents who are OVO users in Grab. In conducting data collection, it was done by distributing questionnaires containing several statements. in this study the variables are divided into several parts including Consumer Satisfaction (X1), Price (X2) and Information Quality (X3) as independent variables, and Consumer Loyalty (Y) as the dependent variable. To measure the magnitude of the influence on these variables, the author uses the method of multiple regression analysis. From the results of the analysis it was found that there were significant and simultaneous effects on the variables of customer satisfaction, price and information quality, and consumer loyalty

Pengaruh Gaya Kepemimpinan Transformational dan Komunikasi terhadap Motivasi dan Dampaknya pada Kinerja Karyawan PT. Xyz

PT. XYZ is a company engaged in the sale of paper and printing machines which will increase greatly in paper demand is increasing every year. therefore the employee\u27s performance is an important factor in increasing the sales of the company so that it can compete with other competitors. To maintain the necessary motivation employee performance so employees can work maximal.This purpose of study was to analyze the effect of transformational leadership style, communication on the motivation and impact on employee performance PT. XYZ. The population used in this study were all employees of PT. XYZ, Tangerang Cipondoh many as 43 people. The analysis technique used is the path analysis (path analysis) .Data obtained from questionnaires distributed to all employees PT. XYZ totaling 43 people to measure transformational leadership style, communication on the motivation and performance of employees by using a Likert scale. From the analysis of the data obtained showed that the Transformational leadership style, communication to motivation and significant influence simultaneously on employee performance

One-dimensional potential for image-potential states on graphene

In the framework of dielectric theory the static non-local self-energy of an electron near an ultra-thin polarizable layer has been calculated and applied to study binding energies of image-states near free-standing graphene. The corresponding series of eigenvalues and eigenfunctions have been obtained by solving numerically the one-dimensional Schr{\"o}dinger equation. Image-potential-state wave functions accumulate most of their probability outside the slab. We find that a Random Phase Approximation (RPA) for the non-local dielectric function yields a superior description for the potential inside the slab, but a simple Fermi-Thomas theory can be used to get a reasonable quasi-analytical approximation to the full RPA result that can be computed very economically. Binding energies of the image-potential states follow a pattern close to the Rydberg series for a perfect metal with the addition of intermediate states due to the added symmetry of the potential. The formalism only requires a minimal set of free parameters; the slab width and the electronic density. The theoretical calculations are compared to experimental results for work function and image-potential states obtained by two-photon photoemission.Comment: 24 pages; 10 figures. arXiv admin note: text overlap with arXiv:1301.448

Two-fluid behavior of the Kondo lattice in the 1/N slave boson approach

It has been recently shown by Nakatsuji, Pines, and Fisk [S. Nakatsuji, D. Pines, and Z. Fisk, Phys. Rev. Lett. 92, 016401 (2004)] from the phenomenological analysis of experiments in Ce1-xLaxCoIn5 and CeIrIn5 that thermodynamic and transport properties of Kondo lattices below coherence temperature can be very successfully described in terms of a two-fluid model, with Kondo impurity and heavy electron Fermi liquid contributions. We analyze thermodynamic properties of Kondo lattices using 1/N slave boson treatment of the periodic Anderson model and show that these two contributions indeed arise below the coherence temperature. We find that the Kondo impurity contribution to thermodynamics corresponds to thermal excitations into the flat portion of the energy spectrum.Comment: 7 pages, 2 figure

Hot electron transport in Ballistic Electron Emission Spectroscopy: band structure effects and k-space currents

Using a Green's function approach, we investigate band structure effects in the BEEM current distribution in reciprocal space. In the elastic limit, this formalism provides a 'parameter free' solution to the BEEM problem. At low temperatures, and for thin metallic layers, the elastic approximation is enough to explain the experimental I(V) curves at low voltages. At higher voltages inelastic effects are approximately taken into account by introducing an effective RPA-electron lifetime, much in similarity with LEED theory. For thick films, however, additional damping mechanisms are required to obtain agreement with experiment.Comment: 4 pages, 3 postscript figures, revte

Highest weight state description of the isotropic spin-1 chain

We introduce an overcomplete highest weight state basis as a calculational tool for the description of the isotropic spin-1 chain with bilinear exchange coupling J1 and biquadratic coupling J2. The ground state can be expressed exactly at the three special points in the phase diagram where the Hamiltonian corresponds to a sum of nearest neighbor total spin projection operators (J1=0>J2, J1=-J2<0, and J1=-J2/3<0). In particular, at the phase transition point J1=-J2<0 it is possible to exactly compute the ground states, excited states, expectation values, and correlation functions by using the new total spin basis.Comment: 8 pages, 1 figure, the most recent version can be found at http://www.physik.uni-kl.de/eggert/papers