arXiv subjects

Karthikeyan Rajagopal

Publications and source records attributed to Karthikeyan Rajagopal.

4 recordsLinked to original sources

arXiv2025

Controlling complex dynamics with synthetic magnetism in optomechanical systems: A route to enhanced sensor performance

This paper investigates the complex nonlinear dynamics of an optomechanical system featuring an optical cavity coupled to two mechanical resonators interconnected by a phase-dependent interaction. We specifically explore the role of this phase-dependent phonon hopping as a mechanism for generating synthetic gauge fields without relying on gain-loss or PT-symmetric elements, offering a potentially more robust approach to manipulate mechanical energy transfer. By deriving the semiclassical dynamical equations, we map out the system's behavior across different parameter regimes. Our findings reveal a rich spectrum of dynamics, including bistability (coexistence of two steady states) and the emergence of complex attractors such as self-excited oscillations, hidden attractors, and chaos. We demonstrate how controlling system parameters, particularly the mechanical coupling phase and optical drive, allows for tunability between these distinct dynamical states. The presence of tunable bistability and sensitive chaotic regimes offers significant potential for practical applications. Specifically, we discuss how these controlled dynamics could be leveraged for state-switching in optical information processing and for enhancing sensitivity in advanced sensor technologies through chaos-based mechanisms. This work deepens our understanding of how synthetic gauge fields, generated via phase-dependent interactions, can sculpt the nonlinear dynamics of optomechanical systems, providing a pathway toward designing robust and tunable devices for signal processing, communication, and sensing.

quant-ph↗

arXiv2024

Periodic systems have new classes of synchronization stability

The Master Stability Function is a robust and useful tool for determining the conditions of synchronization stability in a network of coupled systems. While a comprehensive classification exists in the case in which the nodes are chaotic dynamical systems, its application to periodic systems has been less explored. By studying several well-known periodic systems, we establish a comprehensive framework to understand and classify their properties of synchronizability. This allows us to define five distinct classes of synchronization stability, including some that are unique to periodic systems. Specifically, in periodic systems, the Master Stability Function vanishes at the origin, and it can therefore display behavioral classes that are not achievable in chaotic systems, where it starts, instead, at a strictly positive value. Moreover, our results challenge the widely-held belief that periodic systems are easily put in a stable synchronous state, showing, instead, the common occurrence of a lower threshold for synchronization stability.

cond-mat.stat-mech↗

arXiv2023

Emergence of extreme events in a quasi-periodic oscillator

Extreme events are unusual and rare large-amplitude fluctuations that occur can unexpectedly in nonlinear dynamical systems. Events above the extreme event threshold of the probability distribution of a nonlinear process characterize extreme events. Different mechanisms for the generation of extreme events and their prediction measures have been reported in the literature. Based on the properties of extreme events, such as rare in frequency of occurrence and extreme in amplitude, various studies have shown that extreme events are both linear and nonlinear in nature. Interestingly, in this work, we report on a special class of extreme events which are nonchaotic and nonperiodic. These nonchaotic extreme events appear in between the quasi-periodic and chaotic dynamics of the system. We report the existence of such extreme events with various statistical measures and characterization techniques.

physics.data-an↗

arXiv2021

Discrete hybrid Izhikevich neuron model: nodal and network behaviours considering electromagnetic flux coupling

We analyse the dynamics of the improved discretised version of the well known Izhikevich neuronmodel under the action of external electromagnetic field. It is found that the three-dimensional IZHmap shows rich dynamics. With the variation of the electromagnetic field, period-doubling routeto chaos in a repeating fashion is observed from the bifurcation diagram. Even the forward andbackward continuation bifurcation diagram which do not completely overlap suggests that there is multistability in the system. The phenomenon of bistability (coexistence of periodic and chaotic attractors) is observed. The presence of periodic and chaotic attractor is aided by the maximal Lyapunov exponent diagram. The Lyapunov phase diagram of electromagnetic field and synapses current shows a large parameter region of chaotic and periodic behaviors with the presence of unbounded regions as well. The IZH map shows a plethora of spiking and bursting patterns such as mixed-mode patterns, tonic spiking, phasic spiking, steady spikes, regular spikes, spike bursting, periodic bursting, phasic bursting, chaotic firing, etc with the variation of electromagnetic coupling strength and the synapses current. We also investigate the presence of chimera states in a ring-star, ring, star network of IZH map neurons. Chimera states are found in the case of ring-star and ring network while synchronised clusters were found in the case of star network and are aided by the spatiotemporal plots, space-time plot, recurrence plots. The rich dynamics shown by the discretised IZH map makes it a promising research model to study about neurodynamics.

q-bio.NC↗