Publications

@article{PhysRevE.98.022212,
title = {Dynamical effects of breaking rotational symmetry in counter-rotating Stuart-Landau oscillators},
author = {N Punetha and V Varshney and S Sahoo and G Saxena and A Prasad and R Ramaswamy},
url = {https://ramramaswamy.org/papers/174.pdf},
doi = {10.1103/PhysRevE.98.022212},
issn = {2470-0053 },
year = {2018},
date = {2018-08-01},
journal = {Physical Review E},
volume = {98},
pages = {022212},
publisher = {American Physical Society},
abstract = {Stuart-Landau oscillators can be coupled so as to either preserve or destroy the rotational symmetry that the
uncoupled system possesses. We examine some of the simplest cases of such couplings for a system of two
nonidentical oscillators. When the coupling breaks the rotational invariance, there is a qualitative difference
between oscillators wherein the phase velocity has the same sign (termed co-rotation) or opposite signs (termed
counter-rotation). In the regime of oscillation death the relative sense of the phase rotations plays a major role.
In particular, when rotational invariance is broken, counter-rotation or phase velocities of opposite signs appear
to destabilize existing fixed points, thereby preserving and possibly extending the range of oscillatory behaviour.
The dynamical “frustration” induced by counter-rotations can thus suppress oscillation quenching when coupling
breaks the symmetry.},
keywords = {Amplitude Death, Landau-Stuart, Oscillation Quenching, Symmetry Breaking},
pubstate = {published},
tppubtype = {article}
}

@article{Sharma2017,
title = {Time-delayed conjugate coupling in dynamical systems},
author = {Amit Sharma and Manish Dev Shrimali and Awadhesh Prasad and Ram Ramaswamy},
url = {https://ramramaswamy.org/papers/168.pdf},
doi = {10.1140/epjst/e2017-70026-4},
issn = {19516401},
year = {2017},
date = {2017-01-01},
journal = {European Physical Journal: Special Topics},
volume = {226},
number = {9},
pages = {1903–1910},
abstract = {textcopyright 2017, EDP Sciences and Springer-Verlag GmbH Germany. We study the effect of time-delay when the coupling between nonlinear systems is “conjugate”, namely through dissimilar variables. This form of coupling can induce anomalous transitions such as the emergence of oscillatory dynamics between regimes of amplitude death and oscillation death. The specific cases of coupled Landau-Stuart oscillators as well as a predator-prey model system with cross-predation are discussed. The dynamical behaviour is analyzed numerically and the regions corresponding to different asymptotic states are identified in parameter space.},
keywords = {Amplitude Death, Landau-Stuart, Oscillation Death, Time Delay},
pubstate = {published},
tppubtype = {article}
}

@article{Prasad2010b,
title = {Amplitude death in nonlinear oscillators with nonlinear coupling},
author = {A Prasad, M Dhamala, B M Adhikari, and R Ramaswamy},
url = {https://link.aps.org/doi/10.1103/PhysRevE.81.027201},
doi = {10.1103/PhysRevE.81.027201},
year = {2010},
date = {2010-02-08},
journal = {Physical Review E},
volume = {81},
number = {2},
pages = {027201},
abstract = {Amplitude death is the cessation of oscillations that occurs in coupled nonlinear systems when fixed points are stabilized as a consequence of the interaction. We show here that this phenomenon is very general: it occurs in nonlinearly coupled systems in the absence of parameter mismatch or time delay although time-delayed interactions can enhance the effect. Application is made to synaptically coupled model neurons, nonlinearly coupled Rössler oscillators, as well as to networks of nonlinear oscillators with nonlinear coupling. By suitably designing the nonlinear coupling, arbitrary steady states can be stabilized.},
keywords = {Amplitude Death, Coupled Oscillators},
pubstate = {published},
tppubtype = {article}
}