Role Of Electron-Electron Scattering On Spin Transport In Single Layer Graphene

In this work, the effect of electron-electron scattering on spin transport in single layer graphene is studied using semi-classical Monte Carlo simulation. The D'yakonov-P'erel mechanism is considered for spin relaxation. It is found that electron-electron scattering causes spin relaxation length to decrease by 35% at 300 K. The reason for this decrease in spin relaxation length is that the ensemble spin is modified upon an e-e collision and also e-e scattering rate is greater than phonon scattering rate at room temperature, which causes change in spin relaxation profile due to electron-electron scattering. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.Microelectronics Research Cente

Inversion of moments to retrieve joint probabilities in quantum sequential measurements

A sequence of moments encode the corresponding probability distribution. Probing if quantum joint probability distribution can be retrieved from the associated set of moments -- realized in the sequential measurement of a dichotomic observable at different time intervals -- reveals a negative answer i.e., the joint probabilities of sequential measurements do not agree with the ones obtained by inverting the moments. This is indeed a reflection of the non-existence of a bonafide grand joint probability distribution, consistent with all the physical marginal probability distributions. Here we explicitly demonstrate that given the set of moments, it is not possible to retrieve the three-time quantum joint probability distribution resulting from quantum sequential measurement of a single qubit dichotomic observable at three different times. Experimental results using a nuclear magnetic resonance (NMR) system are reported here to corroborate these theoretical observations viz., the incompatibility of the three-time joint probabilties with those extracted from the moment sequence.Comment: 7 pages, 5 figures, RevTe

Coupled Modes With A1 Symmetry In Tetragonal Batio3

The infrared properties of a system of first-order-coupled phonons are analyzed. The dielectric function and the Raman line shape of the polariton modes are derived. The parameters involved in the theory can be obtained from the Raman spectra of the TO and LO modes or from the Raman spectrum of the TO modes plus infrared-reflectivity measurements. It is shown that we can objectively distinguish real coupling from imaginary, contrary to the current belief. Numerical calculations are performed for the A1-symmetry modes of tetragonal BaTiO3, with good agreement for the polariton shapes and complete disagreement for the infrared reflectivity; damage at the crystal surface is pointed out as the probable cause of the discrepancy. In addition to the coupling between the lowest and the middle mode, previously known, a much larger coupling between the middle mode and the highest is shown to exist. Both couplings are shown to be real or nearly so. The discrepancy between the dielectric constant created by the resonant modes (electronic plus phonons) and the value obtained by electrical measurements is interpreted as a new indication that the crystal has a dynamical disorder; this disorder could also be cause of an anomalous broadening observed in the lowest polariton. © 1974 The American Physical Society.10835223533Information, Control and Communication (INSTICC),Institute for Systems and Technologies o

A new design of square lattice photonic crystal fiber is made by borosilicate material with circular and square air holes to minimize dispersion

Volume 2 Issue 10 (October 2014

Child Abuse and Neglect: A Survey on Primary School Teachers of Kanpur City

Background: A major public concern in today’s world is child abuse and neglect (CAN). Teachers are in unique position to detect possible cases due to their daily contact with children. To assess the knowledge and awareness on recognizing and reporting child abuse and neglect among primary school teachers of Kanpur city.Methods: A descriptive cross-sectional survey was conducted among 220 primary school teachers in 19 randomly selected schools of Kanpur city, Uttar Pradesh, India. A structured close ended questionnaire prepared in two languages (English and National language Hindi) comprising of 19 questions was used.Results: CAN was either never or rarely noticed among 47.3%. The criteria of recognizing the CAN was known by 57% and 90% felt comfortable considering an expert opinion in their schools and so can report confidently. Training to identify CAN was provided by school administration (36.4%) and was done on monthly basis (34.5%).Conclusion: Findings highlight the need for enhancing teacher’s education in CAN, as by reporting suspected CAN, teachers can make an important contribution to the early detection and prevention of child abuse

Current status and future prospects of rapeseed breeding in India

Basic results of applied value were obtained from studies on crosses between self-compatible and incompatible varieties of brown sarson, inter-varietal crosses among brown sarson, yellow sarson and toria, well defined single and three-way crosses and 'multiple cross-multiple pollen' hybrids. Some of the complex hybrids have been advanced to F2 and studies were conducted to test the efficiency of intra-population selective hybridization emphasizing choice of female parents in improving the yield of the populations. It was reported that these basic results are not utilized in the breeding programmes currently in vogue in India. It was pointed out that one of the short-term strategies to tone up the yield level of rapeseed in India is to advocate breeding of composite populations using the methods suggested by basic research. The future of rapeseed can be safeguard by propagating composite populations, advocating the concept of replacement in lieu of regeneration of composites when their yield levels deteriorate and strengthening the breeder-seed-producer-farmer link. Well-defined policies allotting the right priority to rapeseed breeding and advocating mono-and mixed cropping in appropriate areas are the need of the hour to ameliorate the low yield levels of rapeseed