Generalized Gaussian wave packet dynamics: Integrable and Chaotic Systems

The ultimate semiclassical wave packet propagation technique is a complex, time-dependent WBK method known as generalized Gaussian wave packet dynamics (GGWPD). It requires overcoming many technical difficulties in order to be carried out fully in practice. In its place roughly twenty years ago, linearized wave packet dynamics was generalized to methods that include sets of off-center, real trajectories for both classically integrable and chaotic dynamical systems that completely capture the dynamical transport. The connections between those methods and GGWPD are developed in a way that enables a far more practical implementation of GGWPD. The generally complex saddle point trajectories at its foundation are found using a multi-dimensional, Newton-Raphson root search method that begins with the set of off-center, real trajectories. This is possible because there is a one-to-one correspondence. The neighboring trajectories associated with each off-center, real trajectory form a path that crosses a unique saddle; there are exceptions which are straightforward to identify. The method is applied to the kicked rotor to demonstrate the accuracy improvement as a function of $\hbar$ that comes with using the saddle point trajectories.Comment: 18 pages, 9 figures, corrected a typo in Eqs. 29,3

Numerical Simulation of Mode Transition in a Hydrogen-Fueled Scramjet

The Wind-US computational fluid dynamics (CFD) flow solver was used to simulate dual-mode direct-connect ramjet/scramjet engine flowpath tests conducted in the University of Virginia (UVa) Supersonic Combustion Facility (SCF). The objective was to develop a computational capability within Wind-US to aid current hypersonic research and provide insight to flow as well as chemistry details that are not resolved by instruments available. Computational results are compared with experimental data to validate the accuracy of the numerical modeling. These results include two fuel-off non-reacting and eight fuel-on reacting cases with different equivalence ratios, split between one set with a clean (non-vitiated) air supply and the other set with a vitiated air supply (12% H2O vapor). The Peters and Rogg hydrogen-air chemical kinetics model was selected for the scramjet simulations. A limited sensitivity study was done to investigate the choice of turbulence model and inviscid flux scheme and led to the selection of the k-ε model and Harten, Lax and van Leer (for contact waves) (HLLC) scheme for general use. Simulation results show reasonably good agreement with experimental data and the overall vitiation effects were captured

Entanglement induced Sub-Planck structures

We study Wigner function of a system describing entanglement of two cat-states. Quantum interferece arising due to entanglement is shown to produce sub-Planck structures in the phase-space plots of the Wigner function. Origin of these structures in our case depends on entanglement unlike those in Zurek \cite{Zurek}. It is argued that the entangled cat-states are better suited for carrying out precision measurements.Comment: 6 pages 2 figures (revised version include more quantitative discussion

Effect of unsaponifiable fraction of seeds of Hygrophila spinosa T. Ander on testosterone production of rat Leydig cells in vitro

Objective of the study: Seeds of Hygrophila spinosa (HS) T. Ander (Acanthaceae) are traditionally used as aphrodisiac and spermatogenic in Indian System of medicine. Preliminary phytochemical screening of plant revealed the presence of triterpenoids and sterols in seeds. The study was planned to assess the effect of unsaponifiable fraction prepared from seeds of HS on isolated rat Leydig cells for testosterone (T) production using in vitro method.Materials and methods: Leydig cells were isolated from wistar rats, aseptically, in vitro by collagenase cell dispersion method. Cells (2 X 106 cells/ml) were then incubated with unsaponifiable fraction of HS (10, 100 and 1000 µg/ml dose levels in triplicate) in incubator at 37°C under atmosphere of 95% CO2 condition for 3 hours in aseptic condition. Dehydroepiandrosterone (DHEA) was used as positive control in the study. The amount of T secreted in culture media was estimated using HPTLC. Benzene: Ethyl acetate (5:5% v/v) was employed as mobile phase and silica gel G F254 aluminum coated TLC plate as stationary phase.Results: The results indicated dose dependent increase in testosterone concentration in test groups. Isolated rat Leydig cells treated with the test fraction showed increased amount of testosterone present in culture media as compared to that of control.Conclusion: Unsaponifiable fraction prepared from seeds of HS showed ability to enhance biosynthesis of T in Isolated rat leydig cells. In vitro studies showed that the fraction might act locally in testis on Leydig cells and stimulated testosterone synthesis