Articles written in Pramana – Journal of Physics
Volume 16 Issue 2 February 1981 pp 139-146 Chemical Physics
The recently developed method of continuous quantization is applied to the atom-Morse oscillator collinear collision problem. This geometrical formulation of the classical scattering process allows for the extraction of transition probabilities for classically forbidden processes with reasonable accuracy. The accuracy of this method over the simple (histogram) quasi-classical procedure is demonstrated for two-model systems.
Volume 41 Issue 1 July 1993 pp 1- Rapid Communication
We show, using semiclassical methods, that as a symmetry is broken, the transition between universality classes for the spectral correlations of quantum chaotic systems is governed by the same parametrization as in the theory of random matrices. The theory is quantitatively verified for the kicked rotor quantum map. We also provide an explicit substantiation of the random matrix hypothesis, namely that in the symmetry-adapted basis the symmetry-violating operator is random.
Volume 48 Issue 1 January 1997 pp 3-5
Volume 48 Issue 2 February 1997 pp 411-424 Quantum Aspects Of Chaos
The collinear atom-diatom collision system provides one of the simplest instances of chaotic or irregular scattering. Classically, irregular scattering is manifest in the sensitive dependence of post-collision variables on initial conditions, and quantally, in the appearance of a dense spectrum of dynamical resonances. We examine the influence of kinematic factors on such dynamical resonances in collinear (He, H2+) collisions by computing the transition state spectra for collinear (He, HD+) and (He, DH+) collisions using the time-dependent quantum mechanical approach. The nearest neighbor spacing distribution
Volume 48 Issue 2 February 1997 pp 603-615 Applications
Finite clusters of atoms or molecules, typically composed of about 50 particles (and often as few as 13 or even less) have proved to be useful prototypes of systems undergoing phase transitions. Analogues of the solid-liquid melting transition, surface melting, structural phase transitions and the glass transition have been observed in cluster systems. The methods of nonlinear dynamics can be applied to systems of this size, and these have helped elucidate the nature of the microscopic dynamics, which, as a function of internal energy (or ‘temperature’) can be in a solidlike, liquidlike, or even gaseous state. The Lyapunov exponents show a characteristic behaviour as a function of energy, and provide a reliable signature of the solid-liquid melting phase transition. The behaviour of such indices at other phase transitions has only partially been explored. These and related applications are reviewed in the present article.
Volume 56 Issue 1 January 2001 pp 47-56 Research Articles
We show that it is possible to devise a large class of skew-product dynamical systems which have strange nonchaotic attractors (SNAs): the dynamics is asymptotically on fractal attractors and the largest Lyapunov exponent is non-positive. Furthermore, we show that quasiperiodic forcing, which has been a hallmark of essentially all hitherto known examples of such dynamics is
Volume 64 Issue 3 March 2005 pp 305-305
Volume 64 Issue 3 March 2005 pp 307-313
We present a brief report on the conference, a summary of the proceedings, and a discussion on the field of nonlinear science studies and its current frontiers.
Volume 64 Issue 4 April 2005 pp 464-464
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