Fisher information and quantum state estimation of two-coupled atoms in presence of two external magnetic fields

We consider a quantum system of an atom-atom interaction in the presence of two external magnetic and classical fields in x, and z directions. The dynamical behavior of single atom quantum quantifiers such as the atomic Wehrl entropy, atomic Fisher information and quantum entropy are investigated. The quantum entanglement degradation in regard to the atomic state estimation are discussed through the evolution of the atomic Fisher information flow, and the effects of the external classical fields and types of time dependent coupling between the two atoms are examined. We explore the relationship between different statistical quantities in the absence and presence of classical field during the time evolution. The results show that the creation and manipulation of entanglement by external fields greatly benefit within the suitable choice of the kind of time dependent coupling among the two atoms and external. Keywords: Atomic Wehrl entropy, Atomic Fisher information, Atom-atom interaction, Single atom entanglement, Time dependent couplin

Interplay of information quantifiers and the modified Jaynes-Cummings model

The dynamics of the Buck and Sukumar model (B. Buck and C. V. Sukumar, Phys. Lett. A 81, 132 (1981)) is investigated using different semi-classical information-theory tools. Their interplay reveals somewhat unexpected features. A new signature for the classical-quantum barrier is encountered thereby.Instituto de Física La Plat

Entanglement for moving three-level atom under decoherence effect

We discuss the dynamical properties of quantum entanglement and partial entropy for moving three-level atom interacting with single-mode quantized field inside a phase-damped cavity for more general cases. The results show that the atomic motion and decoherence effects play an important role on the evolution of the system dynamics and quantum entanglement. Moreover, we show that the phenomena of long lived nonlocal correlation and short temporal disentanglement can be generated through specific values of phase damping and atomic motion parameter

Direct foreign investment, transnational corporations and the transfer of technology to Egypt

The main concern of this thesis is to assess the performance of the transnational corporations in the transfer of technology to Egypt. The thesis first, reviews the economic literature concerning the economic rationale behind the phenomenon of direct foreign investment and its effect on transnationals' performance in host developing countries. It surveys the debate on the transfer of technology to developing countries and the major issues that arise and then looks at the development of the industrialisation process in Egypt from 1952 to 1974, the date that marks the adoption of the Open Door Economic Policy. The magnitude of foreign investment is assessed by sector and industry and the domestic policy context which might affect the outcome of the transfer of technology is discussed in some detail. The main part of this thesis reports the results of a survey undertaken in Egypt on the contribution of the transnational corporations to the transfer of technology. It was found that the finms surveyed have not engaged in a genuine transfer of technology. The transnationals were found to be keen to transfer mostly unadapted technology from their own home countries or other advanced markets. Accordingly, no genuine effort has been made in fields such as research and development, training of local personnel and co-operation with local research and development institutes. Moreover, these firms were found to concentrate on products with a high import content. In the meantime, their record of exports from Egypt has proved to be very poor. These conclusions are mostly consonant with what has been argued by the critical literature and dissonant with the conventional view of the transnationals' impact on developing countries with regard to both direct foreign investment and the transfer of technology

Entropy squeezing for qubit - field system under decoherence effect

We study in detail the dynamics of field entropy squeezing FES) for a qubit - field system whose dynamics is described by the phase-damped model. The results of calculations show that the initial state and decoherence play a crucial role in the evolution of FES. During the temporal evolution of the system under decoherence effect, an interesting monotonic relation between FES, Wehrl entropy (WE)and negativity is observed

Some Features on Entropy Squeezing for Two-Level System with a New Nonlinear Coherent State

Abstract Entropy squeezing is an important feature in performing different tasks in quantum information processing such as quantum cryptography and superdense coding. These quantum information tasks depend on finding the states in which squeezing can be created. In this article, a new feature on entropy squeezing for a two level system with a class of nonlinear coherent state (NCS) is observed. An interesting result on the comparison between the coherent state (CS) and NCS is explored. The influence of the Lamb-Dick parameter in both absence and presence of the Kerr medium is examined. A rich feature of entropy squeezing in the case of NCS, which is observed to describe the motion of the trapped ion, has been obtained

Interplay of information quantifiers and the modified Jaynes-Cummings model

The dynamics of the Buck and Sukumar model (B. Buck and C. V. Sukumar, Phys. Lett. A 81, 132 (1981)) is investigated using different semi-classical information-theory tools. Their interplay reveals somewhat unexpected features. A new signature for the classical-quantum barrier is encountered thereby.Instituto de Física La Plat

New Algorithm for Drawings of 3-Planar Graphs

Graphs arise in a natural way in many applications, together with the need to be drawn. Except for very small instances, drawing a graph by hand becomes a very complex task, which must be performed by automatic tools. The field of graph drawing is concerned with finding algorithms to draw graph in an aesthetically pleasant way, based upon a certain number of aesthetic criteria that define what a good drawing, (synonyms: diagrams, pictures, layouts), of a graph should be. This problem can be found in many such as in the computer networks, data networks, class inter-relationship diagrams in object oriented databases and object oriented programs, visual programming interfaces, database design systems, software engineering…etc. Given a plane graph G, we wish to find a drawing of G in the plane such that the vertices of G are represented as grid points, and the edges are represented as straight-line segments between their endpoints without any edge-intersection. Such drawings are called planar straight-line drawings of G. An additional objective is to minimize the area of the rectangular grid in which G is drawn. In this paper we introduce a new algorithms that finds an embedding of 3-planar graph. Keywords: 3- Planar Graph; Graph Drawing; drawing on grid