Publications

@article{Tiwari1996b,
title = {Nos´e-Hoover dynamics of a nonintegrable Hamiltonian},
author = {S Tiwari and R Ramaswamy
},
url = {https://www.sciencedirect.com/science/article/pii/0166128095043098},
doi = {10.1016/0166-1280(95)04309-8},
issn = {0166-1280},
year = {1996},
date = {1996-01-15},
journal = {Journal of Molecular Structure: THEOCHEM},
volume = {361},
number = {1},
pages = {111-116},
abstract = {We study the dynamics of a hamiltonian system with two degrees of freedom coupled to a Nosé-Hoover thermostat. In the absence of the thermostat, the system is quasi-integrable: at low energies, most of the motion is on two-dimensional tori, while at higher energies, the motion is mainly chaotic. Upon coupling to the thermostat the system becomes more chaotic, as evidenced by the magnitude of the largest Lyapunov exponent. In contrast to the case of isotropic oscillator systems coupled to thermostats, there is no evidence for a regime of integrable behaviour, even for large values of Q.},
keywords = {Lyapunov exponent, Nonintegrable Hamiltonian Systems},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1987a,
title = {Fractal eigenfunctions in (classically) nonintegrable hamiltonian systems},
author = {R Ramaswamy and S Swaminathan},
url = {https://ramramaswamy.org/papers/033.pdf},
doi = {10.1209/0295-5075/4/2/001},
issn = {12864854},
year = {1987},
date = {1987-01-01},
journal = {EPL},
volume = {4},
number = {2},
pages = {127–131},
abstract = {Bound-state eigenfunctions for a (classically) nonintegrable two degrees of freedom Hamiltonian system are studied. Between the de Broglie wavelength and a localization length, the probability density has a statistically fractal structure in some eigenstates. This novel characterization of eigenstates is intrinsically basis-set and coordinate independent and might therefore provide an objective approach to the question of quantum-chaotic behaviour. textcopyright IOP Publishing Ltd.},
keywords = {Fractals, Nonintegrable Hamiltonian Systems},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1981,
title = {Perturbative examination of avoided crossings},
author = {R Ramaswamy and R A Marcus},
url = {https://doi.org/10.1063/1.441201},
doi = {10.1063/1.441201},
issn = {0021-9606},
year = {1981},
date = {1981-01-15},
journal = {The Journal of Chemical Physics},
volume = {74},
number = {2},
pages = {1379–1384},
abstract = {Quantum perturbation theory is used to examine the eigenvalues of a nonseparable Hamiltonian system in the classically regular and irregular regimes. As a function of the perturbation parameter, the eigenvalues obtained by exact (matrix diagonalization) methods undergo an avoided crossing. In the present paper perturbation theory is used as an approximate method to predict the locations of such avoided crossings in energy‐parameter space. The sparsity of such avoided crossings in the Hénon–Heiles system is seen to produce regular sequences in the eigenvalues even when the classical motion is predominantly chaotic.},
keywords = {Henon-Heiles, Nonintegrable Hamiltonian Systems, Perturbation},
pubstate = {published},
tppubtype = {article}
}