Annalen der Physik最新文献

In this paper, the unconventional light-matter interactions between giant atoms and structured baths (i.e., lattices) are studied with either Hermitian or non-Hermitian next-nearest-neighbor coupling terms. Essentially different dynamics of the atoms and the propagating field in the Hermitian and non-Hermitian cases is revealed, which can be further engineered by tuning parameters such as the atomic transition frequency and the (synthetic) magnetic field associated to the coupling terms. The next-nearest-neighbor couplings play an important role in controlling the emission direction and the field distribution in the lattice, thus providing opportunities for tailoring exotic dipole–dipole interactions. The results in this paper have potential applications in, e.g., engineering unconventional quantum networks and simulating quantum many-body systems.

Through the generalized fractional derivative, it is studied how the decay term and the fractional parameter affect the quantum system, specifically the interaction between the SU(1,1) algebraic system and a three-level atom. By transforming the differential equations into fractional differential equations, general fractional solutions are obtained. The influence of decay and fractional parameter on phenomena such as revival and collapse, entropy squeezing, purity, and concurrence are investigated. The results demonstrate how both decay and fractal parameter affect periods of collapse and revival. It is worth noting that the decay parameter shortens the collapse periods, while an increase in the fractional parameter leads to longer collapse periods. The decay parameter also reduces the degree of entanglement between the different components of the quantum system, while increasing the fractional parameter enhances the entanglement within the quantum system. Hence, it can be concluded that the fractional parameter plays a crucial role in the observed effects on the studied properties.

This work will explore the generations of quantum nonlocalities (as entanglement, Bellnonlocality, and steerability) for two quantum wells (excitons) in dissipative microcavities containing a linear optical medium. An optical fiber links the microcavities. The generated two-exciton nonlocalities are explored by using Bell inequality, steering inequality, and entanglement of formation. For initial correlated and uncorrelated states, the ability of the excitation–photon–fiber interactions to produce new generation and robustness of the two-exciton nonlocality is investigated under the effects of the couplings of the exciton–photon and fiber–photon interactions as well as of the dissipations and the optical susceptibility. It is found that increasing the optical susceptibility enhances the regularity and amplitudes, reduces the frequencies of two-exciton nonlocality dynamics, and supports dissipation degradations. For the initial uncorrelated state, decreasing the difference between the exciton–photon and fiber–photon couplings enhances the generations of the nonlocalities. For the initial correlated state, increasing the exciton–photon and fiber–photon couplings enhances the nonlocality conservation. For open microcavites, increasing the exciton–photon and fiber–photon couplings and the difference between them supports the nonlocality degradations resulting from the external environment dissipations.

This study investigates a theoretical model of a Quantum Otto Cycle (QOC) that utilizes a working fluid spin-chain-star model. The system consists of a central atom interacting with multiple Heisenberg spin chains. Employing unitary transformations, the spin-chain-star system is transformed into a spin-star model. The work done and heat transferred for three distinct working fluid configurations: the $�X$, $��X�X�$, and $��X�Y�Z�$ cases are discussed. The efficiency of the heat engine is examined, and a comparative study between the efficiencies of the three configurations is presented. The study assumes two interaction scenarios for the central atom: either with a single chain (resulting in a two-qubit system after transformation) or with three Heisenberg chains. The results demonstrate that increasing the ratio between the central atom's frequency in the hot bath and the cold bath leads to an enhancement in positive work performed for the $�X$ and $��X�X�$ cases. In the $��X�Y�Z�$ case, the magnitude of this enhancement exhibits a dependence on the system's temperature. The QOC employing the $�X$ configuration working fluid exhibits superior efficiency compared to the other two configurations. Moreover, increasing the central atom's relative frequency improves efficiency for all three cases.

The domain of correlated non-Markovian channels are investigated, exploring the potential memory arising from the correlated action of channels and the inherent memory due to non-Markovian dynamics. The impact of channel correlations is studied using different non-Markovianity indicators and measures. In addition, the dynamical aspects of correlated non-Markovian channels, including entanglement dynamics as well as changes in the volume of accessible states, are explored. The analysis is presented for both unital and non-unital correlated channels. A new correlated channel constructed with modified Ornstein–Uhlenbeck noise (OUN) is also presented and explored. Further, the geometrical effects of the non-Markovianity of the correlated non-Markovian channels are discussed with a study of change in the volume of the accessible states. The link between the correlation factor and error correction success probability is highlighted.

A simplified three-rate-equation model is proposed to study the dynamic behavior of a two-section high-power tapered laser. The model includes a traveling intensity approach to calculate the photon ratios in both sections. The simulations align with the experimental data of a 1060 nm distributed Bragg reflector two-section tapered laser. The effect of driving conditions is analyzed on the peak power and pulse duration. The pulses it obtain experimentally are ≈100 ps with 4.2 W peak power at a 900 MHz repetition rate.

The interaction between two Airy pulses propagating at different wavelengths is numerically investigated. The periodically varying peak intensity of the soliton that emerges from stronger Airy pulse (pump pulse) leads to the formation of periodic temporal boundary. The relatively weaker Airy pulse (probe pulse) on interaction with this boundary gets partially reflected as well as transmitted. As a result, the probe pulse spectrum splits into two parts- the reflected pulse spectrum undergoes redshift while transmitted pulse exhibits blueshift. The probe pulse witnesses maximum reflection when point of interaction lies on the intensity maxima of the emergent soliton from pump Airy pulse. On the other hand, maximum transmission occurs when probe Airy pulse interacts at the intensity minima of the soliton. The reflection and transmission processes can be manipulated by tuning the time delay between pump and probe Airy pulses. In the case of a sufficiently intense pump pulse, the temporal boundary mimics the artificial optical event horizon, and the weak probe Airy pulse is completely reflected. This phenomenon is equivalent to the temporal version of total internal reflection. The results of the study hold potential applications in optical manipulation and temporal waveguiding.