Quantum Revivals in Periodically Driven Systems close to nonlinear resonance

We calculate the quantum revival time for a wave-packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement.Comment: 14 pages, 1 figur

North and south united to conquer viral diarrheas using innovative passive immunity strategies

My fortuitous journey to Argentina began 22 years ago in 1987 when I was invited by Dr Alejandro Schudel, then Director of Virology at INTA, Castelar, to visit Argentina to initiate a joint collaboration. The topic was «Rotavirus infections in calves: development and evaluation of maternal vaccines for passive immunity in calves». Passive immunity and enteric viral infections in swine and cattle were two of my major research interests at the Food Animal Health Research Program, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University (OSU) in the USA. At the time, calf diarrhea was a critical problem in both beef and dairy calves, but the major causes were undefined. Our goals were first to identify the dominant pathogens in the field associated with calf diarrhea and deaths and second to develop methods for their prevention and control. To accomplish these goals, we addressed each of the following key questions in collaborative studies conducted in Argentina (INTA) and the USA (OARDC/The Ohio State University).Academia Nacional de Agronomía y Veterinari

Rotaviruses: Zoonotic potential and adaptation to new hosts

Group A rotaviruses are a leading cause of dehydrating diarrhea in children and also cause diarrhea in young animals worldwide.Academia Nacional de Agronomía y Veterinari

Tight lower bound to the geometric measure of quantum discord

Dakic, Vedral and Brukner [Physical Review Letters \tf{105},190502 (2010)] gave a geometric measure of quantum discord in a bipartite quantum state as the distance of the state from the closest classical quantum (or zero discord) state and derived an explicit formula for a two qubit state. Further, S.Luo and S.Fu [Physical Review A \tf{82}, 034302 (2010)] obtained a generic form of this geometric measure for a general bipartite state and established a lower bound. In this brief report we obtain a rigorous lower bound to the geometric measure of quantum discord in a general bipartite state which dominates that obtained by S.Luo and S.Fu.Comment: 10 pages,2 figures. In the previous versions, a constraint was ignored while optimizing the second term in Eq.(5), in which case, only a lower bound on the geometric discord can be obtained. The title is also consequently changed. Accepted in Phys.Rev.

Research writing and Research Impact Measures: what Librarians need to know?

Library professionals from the MENA region need to contribute more to the global knowledge base of the profession. This session will provide guidance on how to become an effective researcher and writer and how to get published in peer-reviewed journals and proceedings. We will discuss research publication process, quality and optimization of research publication, structuring of research publications, review and indexing process, author profiling and research networks and research impact measures and evaluation metrics. Our aim is to provide more awareness among the library professionals in scholarly publishing and its importance in building professional profile and increased research output from the region

Analytical approximate solutions for two-dimensional incompressible Navier-Stokes equations

Analytical approximate solutions of the two-dimensional incompressible Navier-Stokes equations by means of Adomian decomposition method are presented. The power of this manageable method is confirmed by applying it for two selected  flow problems: The first is the Taylor decaying vortices, and the second is the flow behind a grid, comparison with High-order upwind compact finite-difference method is made. The numerical results that are obtained for two incompressible flow problems  showed that the proposed method is less time consuming, quite accurate and easily implemented. In addition, we prove the convergence of this method when it is applied to the flow problems, which are describing them by  unsteady two-dimensional incompressible Navier-Stokes equations.   Keywords: Navier-Stokes equations, Adomian decomposition, upwind compact difference, Accuracy, Convergence analysis,Taylor's decay vortices, flow behind a grid

PT-Symmetric potential impact on the scattering of a Bose-Einstein condensate from a Gaussian Obstacle

The scattering of a Bose-Einstein Condensate (BEC) from a Gaussian well and Gaussian barrier is investigated over a wide range of depths and heights, respectively. We compare analytical and numerical results for a BEC scattering from Gaussian Obstacles, both in the presence and in the absence of PT-symmetric potential. And we find out that the Complex Ginzburg-Landau Equation (CGLE) method has limitations due to the limited number of variational parameters of the ansatz. We also find that the presence of the PT-symmetric potential controls the reflection and the transmission flux of the BEC through the Gaussian Obstacle

A Note on Normal Forms of Quantum States and Separability

We study the normal form of multipartite density matrices. It is shown that the correlation matrix (CM) separability criterion can be improved from the normal form we obtained under filtering transformations. Based on CM criterion the entanglement witness is further constructed in terms of local orthogonal observables for both bipartite and multipartite systems.Comment: 8 page

On the degree conjecture for separability of multipartite quantum states

We settle the so-called degree conjecture for the separability of multipartite quantum states, which are normalized graph Laplacians, first given by Braunstein {\it et al.} [Phys. Rev. A \textbf{73}, 012320 (2006)]. The conjecture states that a multipartite quantum state is separable if and only if the degree matrix of the graph associated with the state is equal to the degree matrix of the partial transpose of this graph. We call this statement to be the strong form of the conjecture. In its weak version, the conjecture requires only the necessity, that is, if the state is separable, the corresponding degree matrices match. We prove the strong form of the conjecture for {\it pure} multipartite quantum states, using the modified tensor product of graphs defined in [J. Phys. A: Math. Theor. \textbf{40}, 10251 (2007)], as both necessary and sufficient condition for separability. Based on this proof, we give a polynomial-time algorithm for completely factorizing any pure multipartite quantum state. By polynomial-time algorithm we mean that the execution time of this algorithm increases as a polynomial in $m,$ where $m$ is the number of parts of the quantum system. We give a counter-example to show that the conjecture fails, in general, even in its weak form, for multipartite mixed states. Finally, we prove this conjecture, in its weak form, for a class of multipartite mixed states, giving only a necessary condition for separability.Comment: 17 pages, 3 figures. Comments are welcom