Bichromatically driven double well: parametric perspective of the strong-field control landscape reveals the influence of chaotic states

The aim of this work is to understand the influence of chaotic states in control problems involving strong fields. Towards this end, we numerically construct and study the strong field control landscape of a bichromatically driven double well. A novel measure based on correlating the overlap intensities between Floquet states and an initial phase space coherent state with the parametric motion of the quasienergies is used to construct and interpret the landscape features. "Walls" of no control, robust under variations of the relative phase between the fields, are seen on the control landscape and associated with multilevel interactions involving chaotic Floquet states.Comment: 9 pages and 6 figures. Rewritten and expanded version of arXiv:0707.4547 [nlin.CD]. Accepted for publication in J. Chem. Phys. (2008

Local phase space control and interplay of classical and quantum effects in dissociation of a driven Morse oscillator

This work explores the possibility of controlling the dissociation of a monochromatically driven one-dimensional Morse oscillator by recreating barriers, in the form of invariant tori with irrational winding ratios, at specific locations in the phase space. The control algorithm proposed by Huang {\it et al.} (Phys. Rev. A {\bf 74}, 053408 (2006)) is used to obtain an analytic expression for the control field. We show that the control term, approximated as an additional weaker field, is efficient in recreating the desired tori and suppresses the classical as well as the quantum dissociation. However, in the case when the field frequency is tuned close to a two-photon resonance the local barriers are not effective in suppressing the dissociation. We establish that in the on-resonant case quantum dissociation primarily occurs via resonance-assisted tunneling and controlling the quantum dynamics requires a local perturbation of the specific nonlinear resonance in the underlying phase space.Comment: 12 pages, 6 figures (reduced quality), submitted to Phys. Rev.

Soluble Inter-Cellular Adhesion Molecule-1 in Urban Asian North Indians: Relationships with Anthropometric and Metabolic Covariates

Background: High prevalence of diabetes, obesity, and dyslipidemias in people belonging to poor socio-economic strata in urban slums of northern India has been recorded recently. To assess whether this population has high levels of soluble intercellular adhesion molecule-1 (sICAM-1), a cytokine involved in the pathogenesis of atherosclerosis, we investigated subjects belonging to poor socio-economic strata in urban slums and compared them to healthy control subjects from non-slum urban areas of New Delhi