arXiv subjects

A. K. Sarma

Publications and source records attributed to A. K. Sarma.

3 recordsLinked to original sources

arXiv2024

Quantum correlations enhanced in hybrid optomechanical system via phase tuning

This work presents a theoretical framework for enhancing quantum correlations in a hybrid double-cavity optomechanical system that hosts an atomic ensemble. We investigate the role of the coupling phase $ϕ$ between cavity 1 and the atomic ensemble in optimizing quantum correlations, i.e., bipartite/tripartite quantum entanglement and quantum discord. By employing metrics such as logarithmic negativity for bipartite entanglement and minimum residual contangle for genuine tripartite entanglement, we demonstrate that tuning the phase $ϕ$ is essential for maximizing photon-phonon entanglement. Specifically, we find that optimal entanglement occurs at $ϕ=nπ$, with distinct conditions for odd and even integers $n$. Our results also indicate that the quantum entanglement achieved in this system is robust against thermal fluctuations, making it a promising candidate for applications in quantum information processing and quantum computing. Furthermore, this research highlights the significance of phase tuning in controlling quantum correlations, paving the way for advancements in quantum technologies.

quant-ph↗

arXiv2024

Synthetic magnetism enhanced mechanical squeezing in Brillouin optomechanical system

We propose a scheme to generate large amount of mechanical squeezing, far beyond the $\rm{3dB}$ limit, which is based on synthetic magnetism in optomechanical system that hosts a Backward Stimulated Brillouin Scattering (BSBS) process. Our benchmark system consists of an acoustic mode coupled to two optical modes through the BSBS process, and a Duffing mechanical oscillator that couples to the same optical modes through the standard optomechanical radiation pressure. The synthetic magnetism comes from the modulation of the mechanical coupling between the acoustic and the mechanical mode. When there is no synthetic magnetism, a given amount of mechanical squeezing is generated in the system. This squeezing is mainly dependent on the BSBS process, and it is fragile against thermal noise. By switching on the synthetic magnetism, the degree of the generated squeezing is greatly enhanced and goes far beyond the limit of the $\rm{3dB}$. This large magnetism induced squeezing persists even when there is no BSBS process in the system. Moreover, this generated squeezing is robust enough against thermal noise in comparison to the one induced when the synthetic magnetism is off. Furthermore, both the mechanical variance squeezing and effective phonon number exhibit series of peaks and dips depending on the phase modulation of the mechanical coupling. This oscillatory feature is reminiscent of a sudden death and revival of squeezing phenomenon, which can be used to maintain a desired magnitude of squeezing by tuning this phase. Our proposal provides a path toward a flexible scheme that generates large amount of squeezing, far beyond the $\rm{3dB}$ limit. Such a generated squeezed states can be used for quantum applications including quantum information processing, quantum sensing and metrology, and quantum computing.

quant-ph↗

arXiv2024

ICO learning as a measure of transient chaos in PT-symmetric Liénard systems

In this article, we investigate the implications of the unsupervised learning rule known as Input-Correlations (ICO) learning in the nonlinear dynamics of two linearly coupled PT-symmetric Liénard oscillators. The fixed points of the oscillator have been evaluated analytically and the Jacobian linearization is employed to study their stability. We find that on increasing the amplitude of the external periodic drive, the system exhibits period-doubling cascade to chaos within a specific parametric regime wherein we observe emergent chaotic dynamics. We further notice that the system indicates an intermittency route to chaos in the chaotic regime. Finally, in the period-4 regime of our bifurcation analysis, we predict the emergence of transient chaos which eventually settles down to a period-2 oscillator response which has been further validated by both the maximal Finite-Time Lyapunov Exponent (FTLE) using the well-known Gram-Schmidt orthogonalization technique and the Hilbert Transform of the time-series. In the transiently chaotic regime, we deploy the ICO learning to analyze the time-series from which we identify that when the chaotic evolution transforms into periodic dynamics, the synaptic weight associated with the time-series of the loss oscillator exhibits stationary temporal evolution. This signifies that in the periodic regime, there is no overlap between the filtered signals obtained from the time-series of the coupled PT-symmetric oscillators. In addition, the temporal evolution of the weight associated with the stimulus mimics the behaviour of the Hilbert transform of the time-series.

nlin.AO↗