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A. Roy Chowdhury

Bio: A. Roy Chowdhury is an academic researcher from Jadavpur University. The author has contributed to research in topics: Nonlinear system & Integrable system. The author has an hindex of 16, co-authored 280 publications receiving 1118 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors identify two branches of leading singularities in the Painleve formalism for PDEs as developed by Weiss et al., and show that the coupled system is completely integrable in one of the branches, for which case the associated Backlund transformation is explicitly given.
Abstract: Painleve analysis of coupled generalized Schrodinger–Boussinesq system with arbitrary parameters has been carried out. We identify two branches of leading singularities in the Painleve formalism for PDEs as developed by Weiss et al., [J. Math. Phys, 24, 522 (1983) ] . The coupled system is shown to be completely integrable in one of the branches, for which case the associated Backlund transformation is explicitly given. Relevance of the results for coupled nonlinear wave propagation in magnetized plasmas is pointed out.

40 citations

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TL;DR: In this article, an adaptive controller was constructed for the synchronization of two non-linear dynamical systems by analyzing the error equation and utilizing the properties of the corresponding Hurwitz matrix, and suitable criteria were obtained for synchronization.
Abstract: In this paper we study certain aspects of non-linear dynamical systems arising in atmospheric physics from the viewpoint of their synchronization. Apart from phase synchronization, a new method using an adaptive controller is formulated. The model under investigation was originally obtained by Stenflo (Phys. Scr. 53 (1996) 83) in case of acoustic gravity waves and its chaotic properties were studied by Liu (Phys. Scr. 61 (2000) 526), Zhou (J. Math. Phys. 38 (1997) 5225) and Banerjee et al. (Phys. Scripta 63 (2001) 177). Here, we have shown how an adaptive controller can be constructed for the synchronization of two such systems by analysing the error equation and utilizing the properties of the corresponding Hurwitz matrix. As a result, suitable criteria are obtained for synchronization. On the other hand, the phase of such a chaotic time series is defined from the view of Hilbert transform and is shown that the technique of phase synchronization can be equally applied to such systems.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a method for generalized and projective synchronization in modulated time-delayed systems using nonlinear active control is proposed and sufficient condition for generalized synchronization is calculated analytically by Krasovskii-Lyapunov stability theory.

29 citations

Journal ArticleDOI
TL;DR: In this paper, the Darboux-Baklund transformation for the differential-difference nonlinear Schrodinger equation is deduced and it is observed that it is also possible to derive the analogue of the usual Backlund transformation giving the direct connection between the two sets of the old and new nonlinear field variables.
Abstract: Darboux-Baklund transformation for the differential-difference nonlinear Schrodinger equation is deduced. It is observed that it is also possible to derive the analogue of the usual Backlund transformation giving the direct connection between the two sets of the old and new nonlinear field variables, from the Darboux-Backlund itself. Also, it is seen that the different polynomial dependence of the B matrix on the eigenvalue parameter gives rise to various kinds of Backlund transformations — a phenomena not encountered in the usual derivation of the Backlund transformation.

29 citations

Journal ArticleDOI
TL;DR: The quasiperiodic solutions to the discrete nonlinear Schrodinger equation are obtained by a variant of a method due to Date and Tanaka [E. Date and S. Tanaka, Suppl. Prog. Theor. Phys. 59, 107.
Abstract: The quasiperiodic solutions to the discrete nonlinear Schrodinger equation are obtained by a variant of a method due to Date and Tanaka [E. Date and S. Tanaka, Suppl. Prog. Theor. Phys. 59, 107 (1976)]. It is shown explicitly that the nonlinear field variable at the different lattice points can be determined in a recursive fashion in terms of combinations of Reimann’s functions depending on lattice position and time.

28 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors describe the rules of the ring, the ring population, and the need to get off the ring in order to measure the movement of a cyclic clock.
Abstract: 1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects

3,424 citations

Journal Article

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1,682 citations

01 Aug 1993
TL;DR: One-dimensional Bose-gas One-dimensional Heisenberg magnet Massive Thirring model Classical r-matrix Fundamentals of inverse scattering method Algebraic Bethe ansatz Quantum field theory integral models on a lattice Theory of scalar products Form factors Mean value of operator Q Assymptotics of correlation functions Temperature correlation functions Appendices References as discussed by the authors
Abstract: One-dimensional Bose-gas One-dimensional Heisenberg magnet Massive Thirring model Classical r-matrix Fundamentals of inverse scattering method Algebraic Bethe ansatz Quantum field theory integral models on a lattice Theory of scalar products Form factors Mean value of operator Q Assymptotics of correlation functions Temperature correlation functions Appendices References.

1,491 citations

01 Sep 1976
TL;DR: In this article, the authors present a direct and systematic way of finding exact solutions and Backlund transformations of a certain class of nonlinear evolution equations, which they solve exactly using a kind of perturbational approach.
Abstract: The main purpos e of this chapter is to present a direct and systematic way of finding exact solutions and Backlund transformations of a certain class of nonlinear evolution equations. The nonlinear evolution equations are transformed, by changing the dependent variable(s), into bilinear differential equations of the following special form $$ F\left( {\frac{\partial }{{\partial t}} - \frac{\partial }{{\partial {t^1}}},\frac{\partial }{{\partial x}} - \frac{\partial }{{\partial {x^1}}}} \right)f(t,x)f({t^1},{x^1}){|_{t = {t^1},x = {x^1}}} = 0 $$ , which we solve exactly using a kind of perturbational approach.

612 citations

Journal ArticleDOI
TL;DR: In this article, a trace identity based approach to Hamiltonian structures of integrable systems is proposed by making use of trace identity for a variety of isospectral problems that can be unified to one model ψx=Uψ.
Abstract: A new approach to Hamiltonian structures of integrable systems is proposed by making use of a trace identity. For a variety of isospectral problems that can be unified to one model ψx=Uψ, it is shown that both the related hierarchy of evolution equations and the Hamiltonian structure can be obtained from the same solution of the equation Vx=[U,V].

584 citations