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K. S. Nisar

Publications and source records attributed to K. S. Nisar.

At least 19 recordsLinked to original sources
arXiv2026

Squeezing enhanced nonreciprocal quantum correlations via Barnett effect

Cavity optomagnonic platforms offer a promising route for exploring quantum phenomena, particularly quantum correlations, which are vital resources for modern quantum technologies. Here, we propose a theoretical scheme for achieving nonreciprocal quantum correlations such as entanglement, and quantum discord via Barnett effect in a molecular-optomagnonical system, where a yttrium iron garnet sphere is placed in a microwave cavity that is hosting molecules. We show optimal parameter regimes for achieving nonreciprocal quantum correlations through Barnett effect. The generated entanglements are robust against thermal fluctuations, persisting even at high temperatures. Our scheme suggests a new tool for engineering noise-tolerant quantum correlations, and paves a way toward realizing novel nonreciprocal quantum devices by integrating magnons with molecular ensembles.

quant-ph↗
arXiv2025

Enhancing mechanical entanglement in molecular optomechanics

We propose a scheme for enhancing bipartite quantum entanglement in a double-cavity molecular optomechanical (McOM) system incorporating an intracavity optical parametric amplifier (OPA). Utilizing a set of linearized quantum Langevin equations and numerical simulations, we investigate the impact of the OPA on both optical-vibration and vibration-vibration entanglement. Our key findings reveal a counterintuitive trade-off: while the OPA significantly enhances vibration-vibration entanglement, a critical resource for quantum memories and transducers, it simultaneously suppresses optical-vibration entanglement. We demonstrate that maximal vibration-vibration entanglement is achieved when the molecular collective vibrational modes are symmetrically populated, providing a clear experimental guideline for optimizing entanglement sources. In particular, the vibration-vibration entanglement generated in our OPA-enhanced McOM system exhibits remarkable robustness to thermal noise, persisting at temperatures approaching \SI{e3}{\kelvin}, significantly exceeding conventional optomechanical systems, and highlighting the potential for room temperature quantum information processing. These results establish a promising theoretical foundation for OPA-enhanced McOM systems as a robust and scalable platform for quantum technologies, paving the way for future experimental implementations and advanced quantum information processing applications.

quant-ph↗
arXiv2025

Nonreciprocal transmission in hybrid atomic ensemble-optomechanical systems

We investigate perfect optical nonreciprocal transmission in a hybrid optomechanical system that incorporates an atomic ensemble. By introducing complex coupling strengths between the atomic ensemble and a mechanical oscillator, nonreciprocity is induced through interference between distinct optical pathways. The nonreciprocal transmission is governed by the real and imaginary components of the coupling constants, along with the relative phase differences between the optomechanical couplings. Our analysis reveals that, with precise tuning of system parameters, such as coupling strengths, detuning, and phase differences, perfect nonreciprocity can be achieved. We derive the conditions necessary for optimal nonreciprocal transmission and demonstrate its dependence on the complex nature of the coupling. These findings offer valuable insights for the design of nonreciprocal optical devices, including isolators and circulators, with potential applications in quantum communication, signal processing, and photonics.

quant-ph↗
arXiv2025

Nonreciprocal entanglement in a molecular optomechanical system

We propose a theoretical scheme to generate nonreciprocal bipartite entanglement between a cavity mode and vibrational modes in a molecular cavity optomechanical system. Our system consists of $\mathcal{N}$ molecules placed inside a spinning whispering-gallery-mode (WGM) resonator. The vibrational modes of these molecules are coupled to the WGM resonator mode (which is analogous to a plasmonic cavity) and the resonator is also coupled to an auxiliary optical cavity. We demonstrate that nonreciprocal photon-vibration entanglement and nonreciprocal vibration-vibration entanglement can be generated in this system, even at high temperatures. These nonreciprocal entanglements arise due to the Sagnac-Fizeau effect induced by the spinning WGM resonator. We find that spinning the WGM resonator in the counter-clockwise (CCW) direction enhances both types of nonreciprocal entanglement, especially under blue-detuned driving of the optical cavity mode. Furthermore, we show that vibration-vibration entanglement can be significantly enhanced by increasing the number of molecules. Our findings have potential applications in quantum information transmission and in the development of nonreciprocal quantum devices.

quant-ph↗
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

Quadratically enhancing optomechanical entanglement via dark mode control

We propose a scheme to enhance quantum entanglement in an optomechanical system consisting of two mechanically coupled mechanical resonators, which are driven by a common electromagnetic field. Each mechanical resonator is linearly and quadratically coupled to the electromagnetic field. Moreover, the mechanical coupling between the resonators is modulated through a given phase that allows interference control in our structure. By tuning this phase, our system exhibits interference like-structure which is reminiscent of bright and dark mode features. The breaking of the dark mode via the phase adjustment leads to an entanglement generation, which is greatly enhanced through the quadratic coupling. Furthermore, the generated entanglement is robust enough against thermal noise and this resilience is improved when the quadratic coupling is accounted. Our work provides a way to enhance quantum entanglement via quadratic coupling which is assisted by interference control. Such quantum resources can be useful for quantum information processing, quantum computing, and other numerous quantum tasks.

cond-mat.mes-hall↗
arXiv2024

Low threshold quantum correlations via synthetic magnetism in Brillouin optomechanical system

We propose a scheme to generate low driving threshold quantum correlations in Brillouin optomechanical system based on synthetic magnetism. Our proposal consists of a mechanical (acoustic) resonator coupled to two optical modes through the standard optomechanical radiation pressure (an electrostrictive force). The electrostrictive force that couples the acoustic mode to the optical ones striggers Backward Stimulated Brillouin Scattering (BSBS) process in the system. Moreover, the mechanical and acoustic resonators are mechanically coupled through the coupling rate $J_m$, which is $θ$-phase modulated. Without a mechanical coupling, the generated quantum correlations require a strong driving field. By accounting phonon hopping coupling, the synthetic magnetism is induced and the quantum correlations are generated for low coupling strengths. The generated quantum correlations display sudden death and revival phenonmena, and are robust against thermal noise. Our results suggest a way for low threshold quantum correlations generation, and are useful for quantum communications, quantum sensors, and quantum computational tasks.

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

Optomechanical entanglement induced by backward stimulated Brillouin scattering

We propose a scheme to generate robust optomechanical entanglement. This scheme is based on a Backward Stimulated Brillouin Scattering (BSBS) process, which is hosted within an optomechanical structure. Our benchmark system consists of an acoustic (mechanical) mode coupled to two optical modes through the BSBS (radiation pressure) process. For a moderate values of the effective mechanical coupling, the BSBS induces a relatively weak entanglement. This entanglement is greatly enhanced, for at least up to one order of magnitude, when the mechanical coupling strength is strong enough. The generated entanglement is robust enough against thermal fluctuation. Our work provides a new scheme for entanglement generation based on BSBS effect, and can be extended to microwaves and hybrid optomechanical structures. Such a generated entangled states can be used for quantum information processing, quantum sensing, and quantum computing.

quant-ph↗
arXiv2019

Fractional Calculus and certain integrals of Generalized multiindex Bessel function

We aim to introduce the generalized multiindex Bessel function $J_{\left( β_{j}\right) _{m},κ,b}^{\left( α_{j}\right)_{m},γ,c}\left[ z\right] $ and to present some formulas of the Riemann-Liouville fractional integration and differentiation operators. Further, we also derive certain integral formulas involving the newly defined generalized multiindex Bessel function $J_{\left( β_{j}\right) _{m},κ,b}^{\left( α_{j}\right)_{m},γ,c}\left[ z\right] $. We prove that such integrals are expressed in terms of the Fox-Wright function $_{p}Ψ_{q}(z)$. The results presented here are of general in nature and easily reducible to new and known results.

math.CA↗
arXiv2018

Extended (p,q)-Mittag-Leffler function and its properties

In this study our aim to define the extended $(p,q)$-Mittag-Leffler(ML) function by using extension of beta functions and to obtain the integral representation of new function. We also take the Mellin transform of this new function in terms of Wright hypergeometric function. Extended fractional derivative of the classical Mittag-Leffler(ML) function leads the extended (p,q)-Mittag-Leffler(ML) function.

math.CA↗
arXiv2018

Inequalities of extended (p,q)-beta and confluent hypergeometric function

In this present paper, we establish the log-convexity and Turán type inequalities of extended $(p,q)$-beta functions. Also, we present the log-convexity, the monotonicity and Turán type inequalities for extended $(p,q)$-confluent hypergeometric function by using the inequalities of extended $(p,q)$-beta functions.

math.CA↗
arXiv2018

Extended Mittag-Leffler Function and truncated $ν$-fractional derivatives

The main objective of this article is to present $ν$-fractional derivative $μ$-differentiable functions by considering 4-parameters extended Mittag-Leffler function (MLF). We investigate that the new $ν$-fractional derivative satisfies various properties of order calculus such as chain rule, product rule, Rolle's and mean-value theorems for $μ$-differentiable function and its extension. Moreover, we define the generalized form of inverse property and the fundamental theorem of calculus and the mean-value theorem for integrals. Also, we establish a relationship with fractional integral through truncated $ν$-fractional integral.

math.CA↗
arXiv2017

$(p,q)$-Whittaker function and associated properties and formulas

Recently, various extensions and variants of Bessel functions of several kinds have been presented. Among them, the $(p,q)$-confluent hypergeometric function $Φ_{p,q}$ has been introduced and investigated. Here, we aim to introduce an extended $(p,q)$-Whittaker function by using the function $Φ_{p,q}$ and establish its various properties and associated formulas such as integral representations, some transformation formulas and differential formulas. Relevant connections of the results presented here With those involving relatively simple Whittaker functions are also pointed out.

math.CA↗
arXiv2017

Generalized fractional operator representations of Jacobi type orthogonal polynomials

The aim of this paper is to apply generalized operators of fractional integration and differentiation involving Appell's function $F_{3}(:)$ due to Marichev-Saigo-Maeda (MSM), to the Jacobi type orthogonal polynomials. The results are expressed in terms of generalized hypergeometric function. Some of the interesting special cases of the main results also established.

math.CA↗
arXiv2017

A New Class of Integrals Involving Extended Hypergeometric Function

Our purpose in this present paper is to investigate generalized integration formulas containing the extended generalized hypergeometric function and obtained results are expressed in terms of extended hypergeometric function. Certain special cases of the main results presented here are also pointed out for the extended Gauss' hypergeometric and confluent hypergeometric functions.

math.CA↗
arXiv2017

Solution of fractional Distributed Order Reaction-Diffusion Systems with Sumudu Transform

The solution of some fractional differential equations is the hottest topic in fractional calculus field. The fractional distributed order reaction-diffusion equation is the aim of this paper. By applying integral transform to solve this type of fractional differential equations, we have obtained the analytical solution by using Laplace-Sumudu transform.

math.CA↗