Decoherence and entropy generation in an open quantum scalar-fermion system with Yukawa interaction

We have studied the decoherence mechanism in a fermion and scalar quantum field theory with the Yukawa interaction in the Minkowski spacetime, using the non-equilibrium effective field theory formalism appropriate for open systems. The scalar field is treated as the system whereas the fermions as the environment. As the simplest realistic scenario, we assume that an observer measures only the Gaussian 2-point correlator for the scalar field. The cause of decoherence and the subsequent entropy generation is the ignorance of information stored in higher-order correlators, Gaussian and non-Gaussian, of the system and the surrounding. Using the 2-loop 2-particle irreducible effective action, we construct the renormalised Kadanoff-Baym equations, i.e., the equation of motion satisfied by the 2-point correlators in the Schwinger-Keldysh formalism. These equations contain the non-local self-energy corrections. We then compute the statistical propagator in terms of the 2-point functions. Using the relationship of the statistical propagator with the phase space area, we next compute the von Neumann entropy for the system. We have obtained the variation of the entropy with respect to various relevant parameters. We also discuss the qualitative similarities and differences of our results with the scenario when both the system and the environment are scalar fields.Comment: v2, 24pp, 7 figs; Added references and discussion, results unchanged; Accepted in EPJ

Chemistry with Schiff Bases of Pyridine Derivatives: Their Potential as Bioactive Ligands and Chemosensors

Pyridine is a valuable nitrogen based heterocyclic compound which is present not only in large number of naturally occurring bioactive compounds, but widely used in drug designing and development in pharmaceuticals as well as a precursor to agrochemicals and chemical-based industries. Pyridine derivatives bearing either formyl or amino group undergo Schiff base condensation reaction with appropriate substrate and under optimum conditions resulting in Schiff base as product which behave as a flexible and multidentate bioactive ligand. These Schiff bases are of great interest in medicinal chemistry as they can exhibit physiological effects similar to pyridoxal-amino acid systems which are considered to be very important in numerous metabolic reactions. They possess an interesting range of bioactivities including antibacterial, antiviral, antitubercular, antifungal, antioxidant, anticonvulsants, antidepressant, anti-inflammatory, antihypertensive, anticancer activity etc. and considered as a versatile pharmacophore group. Further, several pyridine-based Schiff bases show very strong binding abilities towards the various cations and anions with unique photophysical properties which can be used in ion recognition and they are extensively used in development of chemosensors for qualitative and quantitative detection of selective or specific ions in various kinds of environmental and biological media. These chapter insights the bioactivity and ion recognition ability of Schiff bases derived from pyridine derivatives

Numerical Analysis of Crosss Flow Hydokinetic Turbine by Using Computational Fluid Dynamics

The invention of cross flow turbine industry from straight blades of the Darrieus turbine was modified by Alexander Gorlov into helical shape. There have been several research projects dealing with the design and analysis for tidal applications. This paper deals with the Numerical analysis of a cross flow hydrokinetic turbine (CFHT) with helical blades. Static analysis with optimum blade velocity and constant pressure conditions was performed for the blade with fixed pitch by using Computational Fluid Dynamics (CFD) in Fluent 15. Solidworks was used to carry out 3D modeling of the turbine. The hydrofoil shape of NACA 0018 was created by the airfoil coordinate database. Two different turbulence models Spalart-Allmaras (One-Equation model) and sst-k (Two ndash;Equation model) were employed to compute and compare the results. Pressure profiles, drag and lift coefficients are calculated under a steady flow of 1.5 m/s