Carrier induced ferromagnetism in concentrated and diluted local-moment systems

For modeling the magnetic properties of concentrated and diluted magnetic semiconductors, we use the Kondo-lattice model. The magnetic phase diagram is derived by inspecting the static susceptibility of itinerant band electrons, which are exchange coupled to localized magnetic moments. It turns out that rather low band occupations favour a ferromagnetic ordering of the local moment systems due to an indirect coupling mediated by a spin polarization of the itinerant charge carriers. The disorder in diluted systems is treated by adding a CPA-type concept to the theory. For almost all moment concentrations x, ferromagnetism is possible, however, only for carrier concentrations n distinctly smaller than x. The charge carrier compensation in real magnetic semiconductors (in Ga_{1-x}Mn_{x}As by e.g. antisites) seems to be a necessary condition for getting carrier induced ferromagnetism.Comment: 9 pages (REVTeX), 6 figures, to be published in Phys. Rev.

Violation of Bell's inequality for phase singular beams

We have considered optical beams with phase singularity and experimentally verified that these beams, although being classical, have properties of two mode entanglement in quantum states. We have observed the violation of Bell's inequality for continuous variables using the Wigner distribution function (WDF) proposed by Chowdhury et al. [Phys. Rev. A \textbf{88}, 013830 (2013)]. Our experiment establishes a new form of Bell's inequality in terms of the WDF which can be used for classical as well as quantum systems.Comment: 7 pages, 9 figures and 1 tabl

Noise characteristics of upper surface blown configurations: Analytical Studies

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer

Integration of wholesale prices of groundnut complex

Groundnut oil is one of the major edible oils produced and consumed in India. This paper tries to examine the cointegration of wholesale prices of groundnut pod, oil and cake (groundnut complex) in major markets of India. All-major groundnat markets have been covered. Totally 11 markets were considered for groundnut pods, 10 markets for oil and 5 markets for cake for the study from May 1996 to January 2003. Month-end wholesale price data have been used for the study. There are four terminal markets namely Mumbai, Delhi, Chennai and Calcutta. The major producing centres are Rajkot (Gujarat) and Nandhyal (Andhra Pradesh). Out of 11 groundnut pod and 10 oil wholesale price series, only 4 series are co-integrated, while in case of groundnut cake only two markets are co-integrated out of 5 major markets. In case of groundnut oil and cake, price information flows from major import/export centres like Mumbai and Chennai to major producing centres, as price of groundnut oil and other edible oils (like palm oil, soyaoil) are interrelated and being freely traded internationally, edible oil price discovery takes place in these centres and are linked to border prices. About 50% of domestic edible oil consumption is met by imports and India is a major exporter of groundnut cake. While in case of groundnut pods price information flows from major production centres (Nandyal and Rajkot) to terminal markets such as Mumbai, Chennai and Delhi, there is no large scale imports/exports of groundnut pods from India. Overall price discovery in oil and cake takes place in terminal markets like Mumbai (international trade centres), while for pods price discovery takes place in major producing centres. We have also analysed vertical cointegration among pod, oil and cake markets in the short and long run for testing of co-integration along supply chain. Only in few markets, prices of GN pods and GN oil are vertically integrated in the long run, while in most markets wholesale prices of cake are not integrated either with GN pod or oil wholesale prices in the long run. That too, the vertical integration is strong between wholesale prices of major producing centre (Rajkot) and prices in major consuming centres (Mumbai, Chennai and Hyderabad). Further low margins of processing sector confirms of vertical integration of GN pod and oil/cake wholesale prices at least in GN producing centres

A Robust Fuzzy Logic Control of Two Tanks Liquid Level Process

An attempt has been made in this paper to analyze the efficiency of Fuzzy Logic, PID controllers on Non Interacting Two Tanks (Cylindrical) Liquid Level Process. The liquid level process exhibits Nonlinear square root law flow characteristics. The control problem formulated as level in second tank is controlled variable and the inlet flow to the first tank is manipulated variable. The PID Controller is designed based on Internal Model Control (IMC) Method. The Artificial Intelligent Fuzzy logic controller is designed based on six rules with Gaussian and triangular fuzzy sets. MATLAB - Simulink has been used to simulate and verified the mathematical model of the controller. Simulation Results show that the proposed Fuzzy Logic Controller show robust performance with faster response and no overshoot, where as the conventional PID Controller shows oscillations responses for set point changes. Thus, the Artificial Intelligent FLC is founded to give superior performance for a Non linear problem like two tanks. This paper will help the method suitable for research findings concerning on two tank liquid level system

Experimental Evidence of Time Delay Induced Death in Coupled Limit Cycle Oscillators

Experimental observations of time delay induced amplitude death in a pair of coupled nonlinear electronic circuits that are individually capable of exhibiting limit cycle oscillations are described. In particular, the existence of multiply connected death islands in the parameter space of the coupling strength and the time delay parameter for coupled identical oscillators is established. The existence of such regions was predicted earlier on theoretical grounds in [Phys. Rev. Lett. 80, 5109 (1998); Physica 129D, 15 (1999)]. The experiments also reveal the occurrence of multiple frequency states, frequency suppression of oscillations with increased time delay and the onset of both in-phase and anti-phase collective oscillations.Comment: 4 aps formatted RevTeX pages; 6 figures; to appear in Phys. Rev. Let

Ferromagnetism in the Periodic Anderson Model - a Modified Alloy Analogy

We introduce a new aproximation scheme for the periodic Anderson model (PAM). The modified alloy approximation represents an optimum alloy approximation for the strong coupling limit, which can be solved within the CPA-formalism. Zero-temperature and finite-temperature phase diagrams are presented for the PAM in the intermediate-valence regime. The diversity of magnetic properties accessible by variation of the system parameters can be studied by means of quasiparticle densities of states: The conduction band couples either ferro- or antiferromagneticaly to the f-levels. A finite hybridization is a necessary precondition for ferromagnetism. However, too strong hybridization generally suppresses ferromagnetism, but can for certain system parameters also lead to a semi-metallic state with unusual magnetic properties. By comparing with the spectral density approximation, the influence of quasiparticle damping can be examined.Comment: 20 pages, 13 figure