http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1819 2013-05-26T02:24:22Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2707 Frustrated limit cycle and irregular behaviour in a nonlinear pendulum Ambika, G; Nandakumaran, V M We discuss how the presence of frustration brings about irregular behaviour in a pendulum with nonlinear dissipation. Here frustration arises owing to particular choice of the dissipation. A preliminary numerical analysis is presented which indicates the transition to chaos at low frequencies of the driving force. 1990-01-25T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2571 Universal behaviour in a ``modulated'' logistic map Harikrishnan, K P; Nandakumaran, V M We study the period-doubling bifurcations to chaos in a logistic map with a nonlinearly modulated parameter and show that the bifurcation structure is modified significantly. Using the renormalisation method due to Derrida et al. we establish the universal behaviour of the system at the onset of chaos. 1987-12-07T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2570 On the role of acoustic plasmons in high Tc superconductors Nandakumaran, V M The role of acoustic plasmons in the recently discovered high Tc superconductors is discussed. It is shown that the exchange of acoustic plasmons together with the usual phonon exchange between electrons can give rise to a Tc - 100 K. 1987-07-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2569 Evidence for the existence of Sarkovskii ordering in a two-dimensional map Harikrishnan, K P; Nandakumaran, V M We analyse numerically the bifurcation structure of a two-dimensional noninvertible map and show that different periodic cycles are arranged in it exactly in the same order as in the case of the logistic map. We also show that this map satisfies the general criteria for the existence of Sarkovskii ordering, which supports our numerical result. Incidently, this is the first report of the existence of Sarkovskii ordering in a two-dimensional map. 1988-11-21T00:00:00Z