Biomedical subjects

K P N Murthy

Publications and source records attributed to K P N Murthy.

4 recordsLinked to original sources

PubMed2005

Wang-Landau Monte Carlo simulation of isotropic-nematic transition in liquid crystals.

Wang and Landau proposed recently, a simple and flexible non-Boltzmann Monte Carlo method for estimating the density of states, from which the macroscopic properties of a closed system can be calculated. They demonstrated their algorithm by considering systems with discrete energy spectrum. We find that the Wang-Landau algorithm does not perform well when the system has continuous energy spectrum. We propose in this paper modifications to the algorithm and demonstrate their performance on a lattice model of liquid crystalline system (with Lebwohl-Lasher interaction having continuously varying energy), exhibiting transition from high temperature isotropic to low temperature nematic phase.

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PubMed2003

Interacting growth walk: a model for hyperquenched homopolymer glass?

We show that the compact self-avoiding walk configurations, kinetically generated by the recently introduced interacting growth walk (IGW) model, can be considered as members of a canonical ensemble if they are assigned random values of energy. Such a mapping is necessary for studying the thermodynamic behavior of this system. We have presented the specific heat data for the IGW, obtained from extensive simulations on a square lattice; we observe a broad hump in the specific heat above the theta point, contrary to expectation.

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PubMed2002

Diffusion in a periodically driven damped and undamped pendulum.

We study the diffusion process in a periodically driven damped and undamped pendulum. The effect of angular frequency omega of the external periodic force on the diffusion process is investigated. We show the occurrence of normal and anomalous diffusions in the undamped system. In the presence of damping, normal chaotic diffusion is found. Near certain bifurcation points, the phase velocity is found to be intermittent and the diffusion coefficient is found to exhibit power-law divergence. We argue that the divergence of the diffusion coefficient near the bifurcation points is similar to that of the average laminar lengths near them. The effect of bias on the dynamics is also discussed.

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PubMed2001

Interacting growth walk: a model for generating compact self-avoiding walks.

We propose an algorithm based on local growth rules for kinetically generating self-avoiding walk configurations at any given temperature. This algorithm, called the interacting growth walk (IGW) model, does not suffer from attrition on a square lattice at zero temperature, in contrast to the existing algorithms. More importantly, the IGW model facilitates growing compact configurations at lower temperatures--a feature that makes it attractive for studying a variety of processes such as the folding of proteins. We demonstrate that our model correctly describes the collapse transition of a homopolymer in two dimensions.

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