Publications

@article{sahoo1,
title = {Ageing in mixed populations of Stuart–Landau oscillators: the role of diversity},
author = {S Sahoo and V Varshney and A Prasad and R. Ramaswamy},
url = {https://iopscience.iop.org/article/10.1088/1751-8121/ab4a21},
doi = {10.1088/1751-8121/ab4a21},
issn = {1751-8121},
year = {2019},
date = {2019-10-21},
journal = {Journal of Physics A: Mathematical and Theoretical},
volume = {52},
pages = {464001},
abstract = {The phenomenon of ageing in a population of autonomous oscillators, namely the increase in the number of inactive (or non-oscillatory) units due to coupling interactions is studied in a population of globally coupled Stuart–Landau oscillators. The initial populations are prepared either as a mixture of active and inactive oscillators or as an ensemble of active oscillators with a mixture of distinct frequencies. The ageing transition does not depend on whether the coupling breaks gauge symmetry or not, but is affected by the degree of diversity in the ensemble, namely the existence of different types of subsystems that can cause oscillation quenching when coupled. The scaling exponents depend on the nature of the coupling interaction.},
keywords = {ageing, phase transition, scaling, stasis},
pubstate = {published},
tppubtype = {article}
}

@article{Cruz2010,
title = {The phase–flip transition in coupled electrochemical cells},
author = {J M Cruz, J Escalona, P Parmananda, R Karnatak, A Prasad, and R
Ramaswamy
},
url = {https://doi.org/10.1103/PhysRevE.81.046213},
doi = {10.1103/PhysRevE.81.046213},
year = {2010},
date = {2010-04-26},
journal = {Physical Review E},
volume = {81},
number = {4},
pages = {046213},
abstract = {Time delay is introduced in the coupling between a pair of electrochemical cells. As coupling parameters are varied, the anodic current in the two cells oscillate in synchrony in regimes of periodic as well as chaotic dynamics. When the time delay is varied a phase-flip transition is observed: the relative phase between the synchronized oscillations changes abruptly by
π
. This is accompanied by an experimentally measurable discontinuous change in the frequency of the synchronized oscillators.},
keywords = {electrochemical cells, phase transition},
pubstate = {published},
tppubtype = {article}
}

@article{Hunjan2000,
title = {Melting of the glassy mixed cluster, Ar9Xe10},
author = {J S Hunjan and R Ramaswamy
},
url = {http://nopr.niscpr.res.in/handle/123456789/25846},
issn = {0975-0975},
year = {2000},
date = {2000-03-01},
journal = {Indian Journal of Chemistry A},
volume = {39},
abstract = { We have studied the adiabatic instantaneous normal modes (INMs) for a mixed 19-particle cluster, Ar9Xe10 as a function of temperature. In finite clusters, the INM frequencies, which are well-separated, do not mix as a consequence of the noncrossing rule. The frequencies of the lowest few modes of the system progressively soften as the temperature is increased, and prior to melting, the lowest few modes become unstable: these INM frequencies become imaginary. Eigenvectors corresponding to the lowest modes that appear to be involved in the actual melting process are identified.},
keywords = {clusters, phase transition},
pubstate = {published},
tppubtype = {article}
}

@article{Chakravarty1997,
title = {Instantaneous normal mode spectra of quantum clusters},
author = {C Chakravarty and R Ramaswamy
},
url = {https://pubs.aip.org/aip/jcp/article-pdf/106/13/5564/10783293/5564\_1\_online.pdf},
doi = {10.1063/1.473578},
issn = {0021-9606},
year = {1997},
date = {1997-04-01},
journal = {The Journal of Chemical Physics},
volume = {106},
number = {13},
pages = {5564–5568},
abstract = {The spectrum of instantaneous normal mode (INM) frequencies of finite Lennard-Jones clusters is studied as a function of the extent of quantum delocalization. Configurations are sampled from the equilibrium distribution by a Fourier path integral Monte Carlo procedure. The INM spectra, average force constants and Einstein frequencies are shown to be interesting dynamical markers for the quantum delocalization-induced cluster solid–liquid transition. Comparisons are made with INM spectra of quantum and classical Lennard-Jones liquids. The methodology used here suggests a general strategy to obtain quantal analogs of various classical dynamical quantities},
keywords = {lenard-jones, Monte Carlo, phase transition},
pubstate = {published},
tppubtype = {article}
}

@article{Nayak1996,
title = {Solid <==> liquid transition in model (HF)n clusters},
author = {S Nayak and R Ramaswamy
},
url = {https://doi.org/10.1080/002689796173705},
doi = {10.1080/002689796173705},
year = {1996},
date = {1996-03-01},
journal = {Molecular Physics},
volume = {89},
number = {3},
pages = {809-817},
abstract = { We study the stability, energetics and dynamics of small model hydrogen fluoride clusters (HF) n using isoergic molecular dynamics simulations. The largest Lyapunov exponent is computed over the energy range when the clusters melt, and is found to be more useful in defining the onset of melting than Lindemann’s index. We also examine the power spectrum of potential energy fluctuations of clusters in the liquid state, which show 1/f dependence over a smaller frequency range than rare-gas clusters of comparable size.},
keywords = {clusters, phase transition},
pubstate = {published},
tppubtype = {article}
}