arXiv subjects

A. El Allati

Publications and source records attributed to A. El Allati.

8 recordsLinked to original sources

arXiv2026

Multimode phonon-mediated enhancement of entanglement and competing synchronization in cavity magnomechanics

The generation of quantum correlations in hybrid quantum systems remains a central challenge due to the intrinsic limitations of linear interactions. In cavity magnomechanical platforms, the cavity-magnon coupling gives rise to hybridized cavity-magnon polaritons (CMPs). However, as a beam-splitter-type interaction, it does not by itself generate entanglement between the polariton modes in the absence of additional nonlinear or parametric processes. Here, we propose a mechanism based on multimode phonon mediation, in which multiple vibrational modes act as parallel scattering channels that couple the polaritons through Stokes and anti-Stokes processes. We show that , in the parameter regime explored here, the presence of multiple phonon modes leads to a monotonic enhancement of steady-state entanglement, thereby going beyond the limitations of conventional single-mode schemes. Furthermore, we demonstrate that quantum synchronization between the polariton modes originates from the same underlying scattering processes responsible for entanglement generation, yet exhibits an opposite scaling behavior with increasing phonon number for the phase quadrature, while the amplitude synchronization reveals collective squeezing that grows with the number of phonon channels. Our results provide new insights into the role of multimode interactions in shaping quantum correlations and establish a viable pathway for controlling entanglement and collective dynamics in hybrid magnomechanical platforms.

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arXiv2026

Phase-switchable nonreciprocal entanglement via magnon squeezing in ring-cavity optomagnomechanics

Cavity optomagnomechanics provides a versatile platform to explore macroscopic quantum correlations, particularly nonreciprocal entanglement. In this work, we propose a theoretical scheme to generate switchable bipartite and tripartite entanglement in an optomagnomechanical ring cavity by exploiting phase-controlled magnon squeezing. Indeed, two spatially separated ferrimagnetic YIG microbridges become entangled through their magnetostriction-mediated coupling to mechanical motion and a common cavity field via radiation-pressure interaction. The squeezing process introduces two phase-dependent contributions to the magnon response, namely an effective detuning shift $Δ_{θ_j}$ and a quadrature-damping contribution $κ_{θ_j}$, both of which reverse sign upon a $π$ phase shift, providing an in situ control to switch the entanglement response. The nonreciprocal entanglement is defined operationally through the asymmetric entanglement response under the phase reversal $θ_j \to θ_j + π$, quantified by normalized contrast ratios $C_E$ and $C_{\mathcal{R}}$, which measure the relative difference between the entanglement obtained at $θ_j$ and at the phase-reversed configuration $θ_j+π$. The resulting phase-tuning method provides a flexible and robust route to achieve high-contrast bipartite and tripartite entanglement within stable parameter regions, establishing magnon squeezing as a practical quantum resource for switchable quantum correlations in hybrid platforms.

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arXiv2024

Kitaev Quantum Batteries: Super-Extensive Scaling of Ergotropy in 1D Spin$-1/2$ $XY-Γ(γ)$ Chain

We investigate the performance of a novel model based on a one-dimensional (1D) spin-$1/2$ Heisenberg $XY-Γ(γ)$ quantum chain, also known as 1D Kitaev chain, as a working medium for a quantum battery (QB) in both closed and open system scenarios. We analyze the closed QB scenario by analytically evaluating ergotropy across different spin-spin couplings, anisotropies in spin interactions, Zeeman field strengths, charging field intensities, $Γ$ interactions, and temperature. Our results indicate that the ergotropy is highly dependent on spin-spin coupling and anisotropy. Under variable parameters, an increase in the spin-spin coupling strength displays quenches and exhibits non-equilibrium trends in ergotropy. After a quench, ergotropy may experience a sharp increase or drop, suggesting optimal operational conditions for QB performance. In the open QB scenario, we examine spin chains of sizes $2 \leq N \leq 8$ under the influence of dephasing, focusing on the evolution of ergotropy. We study two charging schemes: parallel charging, where spins are non-interacting, and collective charging, involving spin-spin coupling. In the former, increased Zeeman field strength enhances both the peak ergotropy and charging rate, although without any quantum advantage or super-extensive scaling. In the latter, increasing spin-spin coupling might not achieve super-extensive scaling without introducing anisotropy in the spin-spin interaction. Our results suggest that optimal QB performance and a quantum advantage in scaling can be achieved by leveraging anisotropic spin-spin couplings and non-zero $Γ$ interactions, allowing for faster charging and higher ergotropy under super-extensive scaling conditions up to $α=1.24$ for the given size of the spin chain.

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arXiv2024

Optimal Superdense Coding Capacity in the Non-Markovian Regime

Superdense coding is a significant technique widely used in quantum information processing. Indeed, it consists of sending two bits of classical information using a single qubit, leading to faster and more efficient quantum communication. In this paper, we propose a model to evaluate the effect of backflow information in a superdense coding protocol through a non-Markovian dynamics. The model considers a qubit interacting with a structured Markovian environment. In order to generate a non-Markovian dynamic, an auxiliary qubit contacts a Markovian reservoir in such a way that the non-Markovian regime can be induced. By varying the coupling strength between the central qubit and the auxiliary qubit, the two dynamical regimes can be switched interchangeably. An enhancement in non-Markovian effects corresponds to an increase in this coupling strength. Furthermore, we conduct an examination of various parameters, namely temperature weight, and decoherence parameters in order to explore the behaviors of superdense coding, quantum Fisher information, and local quantum uncertainty using an exact calculation. The obtained results show a significant relationship between non-classical correlations and quantum Fisher information since they behave similarly, allowing them to detect what is beyond entanglement. In addition, the presence of non-classical correlations enables us to detect the optimal superdense coding capacity in a non-Markovian regime.

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arXiv2024

Teleportation two-qubit state by using two different protocols

In this contribution, two versions of teleportation protocol are considered, based on either using a single or two copies of entangled atom-field state, respectively. It is shown that, by using the first version, the fidelity of the teleported state as well as the amount of quantum Fisher information, that contains in the teleported state, are much better than using the second version. In general, one may increases the fidelity of teleported information by increasing the mean photon number and decreasing the detuning parameter. The fidelity of teleporting classical information is much better than teleporting quantum information. Moreover, teleportating classical information that initially encoded in an exited states is much better than that encodes in the ground states. However, the teleported Fisher information that initially encoded in a ground state is much larger than those initially encoded in entangled states.

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arXiv2012

Dynamics of multi-modes maximum entangled coherent state over amplitude damping channel

The dynamics of maximum entangled coherent state travels through an amplitude damping channel is investigated. For small values of the transmissivity rate the travelling state is very fragile to this noise channel, where it suffers from the phase flip error with high probability. The entanglement decays smoothly for larger values of the transmissivity rate and speedily for smaller values of this rate. As the number of modes increases, the travelling state over this noise channel loses its entanglement hastily. The odd and even states vanish at the same value of the field intensity.

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arXiv2010

Communication via entangled coherent quantum network

A quantum network is constructed via maximum entangled coherent states. The possibility of using this network to achieve communication between multi-participants is investigated. We showed that the probability of teleported unknown state successfully, depends on the size the used network. As the numbers of participants increases, the successful probability does not depend on the intensity of the field. The problem of implementing quantum teleportation protocol via a noise quantum network is discussed. We show one can send information perfectly with small values of the field intensity and larger values of the noise strength. The successful probability of this suggested protocol increases abruptly for larger values of the noise strength and gradually for small values. We show that for small size of the used quantum network, the fidelity of the teleported state decreases smoothly, while it decreases abruptly for larger size of network.

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arXiv2010

Transfer information remotely via noise entangled coherent channels

In this contribution, a generalized protocol of quantum teleportation is suggested to investigate the possibility of remotely transfer unknown multiparities entangled coherent state. A theoretical technique is introduced to generate maximum entangled coherent states which are used as quantum channels. We show that the mean photon number plays a central role on the fidelity of the transferred information. The noise parameter can be considered as a control parameter only for small values of the mean photon number.

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