arXiv subjects

M. Amghar

Publications and source records attributed to M. Amghar.

4 recordsLinked to original sources

arXiv2026

Kerr-induced nonreciprocal transparency and group delay in a hybrid cavity magnomechanical system

We propose a scheme for realizing nonreciprocal transparency, Fano resonances, and slow/fast light in a hybrid cavity magnomechanical system containing two YIG spheres and a mechanical resonator. The nonreciprocal behavior originates from the magnon Kerr nonlinearity, which induces direction-dependent frequency shifts and modifies the interference pathways among cavity photons, magnons, and phonons. We show that the hybrid system supports multiple transparency windows arising from magnon- and magnomechanical-induced interference processes. The Kerr interaction strongly reshapes these transparency features, producing asymmetric Fano resonance line shapes and enabling controllable nonreciprocal transmission. Furthermore, the associated dispersion exhibits pronounced directional asymmetry, leading to giant differences in the group delay for opposite propagation directions and allowing reversible switching between slow- and fast-light regimes. We investigate the roles of hybrid coupling strengths and dissipation channels and identify parameter regimes where the nonreciprocal response is maximized. These findings establish Kerr-engineered magnomechanical systems as promising platforms for integrated nonreciprocal microwave photonics and quantum information technologies.

quant-ph↗

arXiv2026

Nonreciprocal transparency windows, Fano resonance, and slow/fast light in a membrane-in-the-middle magnomechanical system induced by the Barnett effect

Nonreciprocal phenomena are currently a major focus of research within the fields of classical and quantum technology. In this work, we theoretically investigate the interplay among multiple magnomechanically induced transparency (MMIT) windows, Fano resonances, slow/fast light, and nonreciprocal absorption and group delay in a hybrid cavity magnomechanical system. This system is composed of two yttrium iron garnet (YIG) spheres and a membrane positioned at the center of the cavity. By analyzing the absorption spectrum of a weak probe field in the presence of a strong control field, we demonstrate the emergence of five transparency windows resulting from combined photon-phonon, photon-magnon, and phonon-magnon interactions. The photon-phonon coupling associated with the membrane plays a crucial role in enhancing and tailoring these transparency features. We further examine the impact of the Barnett effect on the absorption and dispersion characteristics, showing that it enables the controllable manipulation of transparency windows and the generation of tunable Fano resonance profiles. The influence of cavity decay and magnon dissipation rates on the spectral response is also analyzed. In addition, we demonstrate that the group delay of the transmitted probe field can be effectively tuned via the photon-phonon coupling strength and the Barnett effect, allowing for a controllable transition between slow and fast light regimes. Finally, nonreciprocal absorption and group delay are achieved through appropriate adjustment of the coupling parameters. These findings highlight the potential of the proposed hybrid system for applications in optical signal processing and quantum information technologies.

quant-ph↗

arXiv2025

Geometry and quantum brachistochrone analysis of multiple entangled spin-1/2 particles under all-range Ising interaction

We present a unified geometric and dynamical framework for a physical system consisting of $n$ spin-$1/2$ particles with all-range Ising interaction. Using the Fubini-Study formalism, we derive the metric tensor of the associated quantum state manifold and compute the corresponding Riemann curvature. Our analysis reveals that the system evolves over a smooth, compact, two-dimensional manifold with spherical topology and a dumbbell-like structure shaped by collective spin interactions. We further investigate the influence of the geometry and topology of the resulting state space on the behavior of geometric and topological phases acquired by the system. We explore how this curvature constrains the system's dynamical behavior, including its evolution speed and Fubini-Study distance between the quantum states. Within this geometric framework, we address the quantum brachistochrone problem and derive the minimal time required for optimal evolution, a result useful for time-efficient quantum circuit design. Subsequently, we explore the role of entanglement in shaping the state space geometry, modulating geometric phase, and controlling evolution speed and brachistochrone time. Our results reveal that entanglement enhances dynamics up to a critical threshold, beyond which geometric constraints begin to hinder evolution. Moreover, entanglement induces critical shifts in the geometric phase, making it a sensitive indicator of entanglement levels and a practical tool for steering quantum evolution. This approach offers valuable guidance for developing quantum technologies that require time-efficient control strategies rooted in the geometry of quantum state space.

quant-ph↗

arXiv2025

Barnett Effect-Induced Nonreciprocal Entanglement and Gaussian interferometric power in Magnomechanics with Optical Parametric Amplifier

Nonreciprocity is a powerful tool in quantum technologies. It allows signals to be sent in one direction but not the other. In this article, we propose a method for achieving non-reciprocal entanglement and Gaussian interferometric power (GIP) via the Barnett effect. The YIG is coupled to a microwave cavity that interacts with an optical parametric amplifier (OPA). Due to the Barnett effect, giant nonreciprocal entanglement can emerge. By fine-tuning the cavity detuning, the GIP can exhibits nonreciprocal behavior. All entanglements with ideal nonreciprocity can be achieved by tuning the photon frequency detuning, appropriately choosing the cavity-magnon coupling regime, the nonlinear gain, and the phase shift of the OPA. Interestingly, the amount of entanglement nonreciprocity and its resilience to thermal occupation are remarkably enhanced by increasing the gain of the OPA. This nonreciprocity can be significantly enhanced even at relatively high temperatures. Our research offers a pathway for the realization of nonreciprocal single-phonon devices, with potential applications in quantum information processing and quantum communication. This proposed scheme could pave the way for the development of novel nonreciprocal devices that remain robust under thermal fluctuations.

quant-ph↗