arXiv subjects

Khadija El Anouz

Publications and source records attributed to Khadija El Anouz.

11 recordsLinked to original sources

arXiv2026

Correlation Enhanced Autonomous Quantum Battery Charging via Structured Reservoirs

In this work, we investigate autonomous charging of a quantum battery coupled to a structured reservoir composed of two qubits, each locally coupled to its own bosonic thermal bath. Moreover, the reservoir interacts with a charger-battery architecture through three configurations: (I) direct coupling between reservoir qubits and battery, (II) collective coupling among reservoir qubits, charger, and battery, and (III) collective coupling between reservoir qubits and charger together with a local charger-battery interaction. Using incoherent and coherent initial states, we analyze stored energy, ergotropy, and charging power of the battery, and derive upper and lower bounds on extractable work in terms of free energy of coherence and correlations exchanged between subsystems. Our results show that global and local coherences, as well as total correlations, act as quantum resources that enhance autonomous charging. Additionally, we demonstrate that the free energy stored in the quantum battery splits into contributions from coherence and correlations, providing numerical evidence supporting the derived ergotropy bounds. Importantly, this work highlights how structured reservoirs enable autonomous and resource-enhanced quantum battery operation.

quant-ph↗

arXiv2026

Nonreciprocal Macroscopic Entanglement through Magnon Squeezing in a Cavity Magnomechanics

Cavity magnomechanics has opened a new frontier in quantum electrodynamics, yielding several significant theoretical and experimental results. In this paper, we propose a different theoretical mechanism to achieve nonreciprocal macroscopic entanglement among magnons, photons, and phonons, based on magnon squeezing. Specifically, reversing the squeezing phase, namely theta -> theta + pi reverses the frequency shift and the effective dissipation rate simultaneously, producing two experimentally distinct configurations that enable nonreciprocal entanglement. Indeed, in contrast to conventional approaches that control only frequency shifts, we show how precise control of the amplitude and phase of the squeezed mode allows us to obtain a tunable nonreciprocity of entanglement. The magnons resulting from the collective motion of the spin in a macroscopic ferrimagnet become coupled to the microwave photons via magnetic dipole interaction and to the phonons via magnetostrictive interaction. Moreover, we show that the proposed scheme achieves ideal nonreciprocity, which can be optimized by cavity-magnon coupling and bath temperature control. Finally, by using the parameters that are experimentally feasible with current technologies, this work provides promising perspectives for hybrid magnon-based quantum technologies.

quant-ph↗

arXiv2026

Generation of Quantum Entanglement in Autonomous Thermal Machines: Effects of Non-Markovianity, Hilbert Space Structure, and Quantum Coherence

We present a theoretical investigation of entanglement generation in an external quantum system via interaction with a quantum autonomous thermal machine (QATM) under non-Markovian dynamics. The QATM, composed of two qubits each coupled to independent thermal reservoirs, interacts with an external system of two additional qubits. By analyzing the Hilbert space structure, energy level configurations, and temperature gradients, we define a common interaction between the QATM qubits and the external system qubits, which allows the definition of two thermodynamic cycles (A and B) governed by virtual temperatures and energy-conserving transitions. We demonstrate that the QATM can act as a structured reservoir capable of inducing non-Markovian memory effects, as highlighted by negative entropy production rates. Using mutual information and concurrence, we show that entanglement is generated only under cycle A, which is associated with stronger non-Markovian behavior and higher coherence correlations. Our results demonstrate that temperature differences, Hilbert space structure, and coherence serve as quantum resources for controlling and enhancing entanglement in quantum thermodynamic settings, with parameters consistent with experimental superconducting qubit platforms.

quant-ph↗

arXiv2025

Nonequilibrium quantum thermometry with noncommutative system-bath couplings

Accurate temperature estimation in the quantum and cryogenic regimes remains a fundamental challenge. Here, we investigate nonequilibrium quantum thermometry using a single-qubit probe coupled to a bosonic bath through noncommuting interaction operators, which unify pure dephasing and dissipative dynamics within a spin-boson model. We show that the interference between these two coupling channels induces strong non-Markovian feedback between populations and coherences, leading to coherence trapping and enhanced thermal sensitivity. Remarkably, by tuning the coupling structure, the probe's temperature sensitivity exhibits a quadratic low-temperature scaling, even under weak coupling. Moreover, while coherence-based measurements are formally suboptimal, they become the most informative in the early nonequilibrium regime, where memory effects dominate. Our findings identify noncommutative system-bath couplings as a practical and tunable resource for achieving high-precision quantum thermometry in realistic open-system architectures.

quant-ph↗

arXiv2025

Coherence-Driven Quantum Battery Charging via Autonomous Thermal Machines: Energy Transfer, Memory Effects, and Ergotropy Enhancement

In this work, we study a hybrid quantum system composed of a quantum battery and a coherence-driven charger interacting with a Quantum Autonomous Thermal Machine (QATM). The QATM, made of two qubits, each coupled to Markovian bosonic thermal reservoirs at different temperatures, acts as a structured environment that mediates energy and coherence between the charger and the battery. By applying a coherent driving field on the charger, we investigate the coherence injection effect on the dynamics, including non-Markovianity, power of charging, coherence storage, and ergotropy. We show that the QATM filters the decoherence induced by the thermal baths and induces non-Markovian memory effects due to correlation backflow. Our results demonstrate that coherence driving enhances the battery's ergotropy; coherence driving raises the maximum ergotropy by approximately 40% compared to the case without coherence driving, and the power of charging by preserving the internal energy of the charger.

quant-ph↗

arXiv2025

Tunable Entangling and Steering of Ferrimagnetic Magnons via an OptoMagnoMechanical Ring

Recently, magnomechanical systems have emerged as promising platforms for quantum technologies, exploiting magnon-photon-phonon interactions to store high-fidelity quantum information. In this paper, we propose a scheme to entangle two spatially separated ferrimagnetic YIG crystals by injecting a microwave field into an optomagnonic ring cavity. The proposed optomagnomechanical configuration utilizes the coupling between magnetostriction-induced mechanical displacements and the optical cavity via radiation pressure. Magnons - collective spin excitations in macroscopic ferromagnets - are directly driven by an electromagnetic field. We demonstrate the generation of macroscopic magnon entanglement by exciting the optical cavity with a red detuned microwave field and the YIG crystals with a blue detuned field. Our analysis reveals that magnon entanglement vanishes for identical magnomechanical couplings but remains robust against thermal fluctuations. The magnon modes entangled in two ferrimagnetic crystals represent genuine macroscopic quantum states with potential applications in the study of macroscopic quantum mechanics and quantum information processing based on magnonics. The configuration is based on experimentally accessible parameters, providing a feasible route of quantum technologies.

quant-ph↗

arXiv2024

Harnessing coherence generation for precision single- and two-qubit quantum thermometry

Quantum probes, such as single- and two-qubit probes, can accurately measure the temperature of a bosonic bath. The current investigation assesses the precision of temperature estimate using quantum Fisher information and the accompanying quantum signal-to-noise ratio. Employing an ancilla as a mediator between the probe and the bath improves thermometric sensitivity by transmitting temperature information into the probe qubit's coherences. In addition, we analyze two interacting qubits that were initially entangled or separated as quantum probes for various environmental configurations. Our findings show that increased precision is gained when the probe approaches its steady state, which is determined by the coupling between the two qubits. Furthermore, we can obtain high efficiency temperature estimation for any low temperature by changing the interaction between the two qubits.

quant-ph↗

arXiv2024

Phonon-Assisted Tunneling through Quantum Dot Systems Connected to Majorana Bound States

We theoretically analyze phonon-assisted tunneling transport in a quantum dot side connected to a Majorana bound state in a topological superconducting nanowire. We investigate the behavior of the current through the dot, for a range of experimentally relevant parameters, in the presence of one long-wave optical phonon mode. We consider the current-gate voltage, the current-bias voltage and the current-dot-Majorana coupling characteristics under the influence of the electron-phonon coupling. In the absence of electron-phonon interaction, the Majorana bound states suppress the current when the gate voltage matches the Fermi level, but the increase in the bias voltage counteracts this effect. In the presence of electron-phonon coupling, the current behaves similarly as a function of the renormalized gate voltage. As an added feature at large bias voltages, it presents a dip or a plateau, depending on the size of the dot-Majorana coupling. Lastly, we show that the currents are most sensitive to, and depend non-trivially on the parameters of the Majorana circuit element, in the regime of low temperatures combined with low voltages. Our results provide insights into the complex physics of quantum dot devices used to probe Majorana bound states.

cond-mat.mes-hall↗

arXiv2023

Dual Non-local Cnot gate

Distant quantum control via quantum gates represents an essential step toward realizing distributed quantum networks. An efficient theoretical protocol for the dual non-local implementation of controlled-not (CNOT) gates between two separated partners is presented in this regard. The suggested protocol requires 1~ebit with local operations and classical communication channels. The efficiency of the teleportation scheme is quantified through an infidelity measure. The numerical results show that the infidelity of performing the CNOT gate between legitimate partners depends on the initial qubit settings. It is also shown that the protocol is performed efficiently if the CNOT control qubit and the auxiliary qubit are prepared in the same direction. Furthermore, we provide a noise analysis for the suggested scheme. We find that by maintaining the noise strengths under the threshold $\frac{1}{4}$, one can achieve the dual non-local CNOT gate optimally.

quant-ph↗

arXiv2023

Strong quantum correlation in a pair hybrid optomechanical cavities

We show the quantum correlation between two coupled hybrid optomechanical cavities by quantifying the non-classical correlation using Gaussian quantum discord. This involves analyzing and solving Heisenberg Langevin equations to obtain the (12*12)dimensional covariance matrix of this system. Based on the experimentalist conditions, we simulate quantum correlation of bipartite steady-state with continuous conditions using Guassian quantum discord. We know that the generation of quantum correlation and its robustness essentially depend on the physical parameters of the system. We provide the stability analysis by means of the RuthsHurwitz criterion to confirm the choices made during the analysis of quantum discord dynamics.

quant-ph↗

arXiv2020

Engineering entanglement and teleportation via solving Lindblad master equation

An experimentally realizable model based on the interaction between an excited two-level atom and a radiation field inside two quantum electrodynamics cavities is proposed. It consists of sending an excited two-level atom through two serial cavities which contain the radiation field. Hence, the Lindblad master equation described the reduced density matrix of the joint-joint field system inside the cavities is exactly solved in Markovian and non-Markovian regimes. However, the rate of entanglement inherent in the total field-field system are evaluated using various witnesses of entanglement such as concurrence, logarithmic negativity and quantum discord. Moreover, the non-classicality by means of negativity volume and Wigner function is discussed. Finally, two schemes of quantum teleportation are suggested.

quant-ph↗