arXiv subjects

P. Djorwe

Publications and source records attributed to P. Djorwe.

9 recordsLinked to original sources

arXiv2025

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

Saturable nonlinearity induced quantum correlations in optomechanics

We propose a scheme that induces quantum correlations in optomtomechanical systems. Our benchmark system consists of two optically coupled optical cavities which interact with a common mechanical resonator. The optical cavities host saturable nonlinearity which triggers either gain or losses in each cavity. Without these nonlinearities, there are no quantum correlations, i.e., entanglement and steering, generated in the system. By turning on the nonlinearities, gain and losses are switched on, enabling flexible generation of both quantum entanglement and quantum steering in our proposal. These generated quantum correlations seem to be insensitive to the induced gain, while the induced losses through saturation effect efficiently enhance quantum correlations. Moreover, the robustness of the generated quantum correlations against thermal fluctuations is further improved under nonlinear saturation scenario. This work suggests a way of using nonlinear saturation effects to engineer quantum correlations even at room temperature, which are useful for quantum information processing, quantum computational tasks, and quantum technologies.

quant-ph↗

arXiv2025

Quantum correlations in molecular cavity optomechanics

Quantum correlations are interesting resources for modern quantum technologies such as quantum information processing, quantum communication, quantum teleportation, and quantum computation tasks. However, engineering these quantum states turns to be not an easy task. Here, we unveil a theoretical framework for generating and controlling quantum correlations within a double-cavity molecular optomechanical (McOM) system. Our approach leverages strong interactions between confined optical fields and collective molecular vibrations, creating a versatile environment for exploring robust quantum correlations. Our findings reveal that by judiciously optimizing the coupling strength between the cavity field and the molecular collective mode leads to significant enhancement of entanglement, quantum steering, and quantum discord. We demonstrate that cavity-cavity quantum correlations can be effectively mediated by the molecular collective mode, enabling a unique pathway for inter-cavity quantum connectivity. Moreover, the quantum entanglement generated in our McOM system exhibits robustness against thermal noise, persisting up to temperatures approaching $1000 K$. This strong resilience, qualifies molecular optomechanics as a compelling architecture for scalable, room-temperature quantum information processing and the practical realization of quantum networks. Additionally, the phase-dependent behaviour of quantum discord provides a fundamental basis for developing ultra-sensitive gas sensors, with potential applications in environmental monitoring, medical diagnostics, and industrial safety.

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 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

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↗

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 $\phi$ 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 $\phi$ is essential for maximizing photon-phonon entanglement. Specifically, we find that optimal entanglement occurs at $\phi=n\pi$, 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↗

arXiv2018

Low-power phonon lasing through position-modulated Kerr-type nonlinearity

We demonstrate low-power amplification process in cavity optomechanics (COM). This operation is based on the nonlinear position-modulated self-Kerr interaction. Owing to this nonlinear term, the effective coupling highly scales with the photon number, resulting in a giant enhancement of the cooperativity. Even for small nonlinearity, the system reaches the amplification threshold for weak driving strength, leading to low-power phonon lasing. This amplifier can be phase-preserving and provides a practical advantage related to the power consumption issues. This work opens up new avenues to realize low-power and efficient amplifiers in optomechanics and related fields.

cond-mat.mes-hall↗

arXiv2018

Frequency locking and controllable chaos through exceptional point in optomechanics

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically the existence of multiple exceptional points (EPs), a form of degeneracy where the eigenvalues of the system coalesce. At each EP, phase transition occurs, and the system switches from weak to strong coupling regimes and vice versa. In the weak coupling regime, the system locks on an intermediate frequency, resulting from coalescence at the EP. In strong coupling regime, however, two or several mechanical modes are excited depending on system parameters. The mechanical resonators exhibit Rabi-oscillations when two mechanical modes are involved, otherwise the interaction triggers chaos in strong coupling regime. This chaos is bounded by EPs, making it easily controllable by tuning these degeneracies. Moreover, this chaotic attractor shows up for low driving power, compared to what happens when the coupled OMCs are both drived in blue sidebands. This works opens up promising avenues to use EPs as a new tool to study collective phenomena (synchronization, locking effects) in nonlinear systems, and to control chaos.

cond-mat.mes-hall↗