Annalen der Physik最新文献

Network Nonlocality is an advanced study of quantum nonlocality that comprises network structure beyond Bell's theorem. The development of quantum networks has the potential to bring a lot of technological applications in several quantum information processing tasks. Here, the focus is on how the role of the independence of the measurement choices by the end parties in a network works and can be used to affect the security in a quantum network. In both three-parties two-sources bilocal network and four-parties three-sources star network scenarios, this study is able to show, a practical way to understand the relaxation of the assumptions to enhance a real security protocol if someone wants to breach in a network communication. Theoretically, it have been proved that by relaxing the independence of the measurement choices of only one end party, a Standard Network Nonlocality (SNN) and more stronger Full Network Nonlocality (FNN) can be created and the maximum quantum violation by the classical no-signalling local model can be obtained. The distinguish between two types of network nonlocality, SNN and FNN, can also be made. It has been shown that FNN is a stronger correlation than SNN in the sense that the former comes in a scenario where all the sources must be nonlocal in nature.

Reflection and Transmission of Airy Pulse from Controllable Periodic Temporal Boundary

The images on the cover show interaction between strong and weak Airy pulses for smaller (upper image) and larger (lower image) delays between them. Soliton emerging from strong Airy pulse acts as a periodic temporal boundary for the weak pulse that suffers reflection and/or transmission at the boundary. For further details and characteristics, see the study by Deependra Singh Gaur and Akhilesh Kumar Mishra in article number 2400141.

In this paper, an ultra-wideband metamaterial absorber (UWMA) is proposed and demonstrated by using a transparent and flexible sandwich structure, which consists of a top patterned double-square loop (DSL) of conductive film, the polymer interlayer, the bottom conductive film. The work presents the UWMA's equivalent circuit model for a macroscopic analysis of its physical mechanism. Further, optimizing UWMA's structural parameters using this equivalent circuit model can greatly enhance its efficiency. The absorption coefficient of the designed structure achieves over 90% within the wide frequency range from 10.82  to 34.59 GHz due to the overlapping of three absorption bands. The experimental results indicate that the absorption coefficient of the fabricated structure exceeds 60% in the frequency range of 10.45–35.28 GHz, and reaches 90% in the majority of frequency range of 10.71–28.51 GHz, while its averaged optical transparency in the visible spectrum exceeds 75%. The UWMA achieves high transparency due to a small ratio of the surface area occupied by the ITO pattern to the total area and realizes multiple-resonance ultra-wideband absorption with conformality while maintaining a thickness of only 2.2 mm, which has diverse applications in the field of electromagnetics, including aircraft stealth, transparent chambers, and flexible electronic screens.

A non-singular black hole solution is briefly presented which violates energy conditions only at its interior by postulating a consistent shift to negative energies and gravitationally repulsive negative masses at the event horizon. This shift is the unitary parity-time $��P�T�$ transformation of relativistic quantum mechanics and the proper antichronous transformation of the full Lorentz group. The transformation at the event horizon respects Einstein's equivalence principle, and the considered negative mass interaction does not result in the runaway motion paradox or vacuum instability. The correspondence of these regular black holes with observed ones is studied by proposing another mechanism of black hole growth independent of accretion and merging due to interior increasing entropy, which attempts to solve the unexplained size and formation of high-redshift supermassive black holes, the intermediate mass gap, and the information paradox.

The manipulation of the electron spin direction at very low electron energies is demonstrated by exploiting the exchange field present within a magnetic thin film. The design of the lab-on-chip integrated magnetic tunnel transistor allows  to test different magnetic materials. The variation of film thickness, exchange field strength or electron energy are shown to have an impact on the resulting spin direction of electrons crossing a ferromagnetic material. A controlled engineering of the exchange field in thin magnetic films can therefore serve as a basis of future devices enabling controlled spin manipulation.

This work examines the energy localization in non-Hermitian systems, with a particular focus on the influence of topological defects in spherical models. Alterations in the mode distribution are explored within non-Hermitian Su-Schrieffer-Heeger (SSH) chains affected by these defects, utilizing the Maximum Skin Corner Weight (MaxWSC) metric. An innovative spherical model is introduced, created by segmenting spheres into 1D chain structures, to study the non-Hermitian skin effect (NHSE) within a spherical geometric framework. Experimental validations conducted on Printed Circuit Boards (PCBs) corroborate the theoretical insights. These findings not only substantiate the theoretical approach but also illustrate the capability of engineered circuit systems to mimic complex non-Hermitian phenomena, highlighting the utility of spherical geometries in exploring NHSE and topological phenomena in non-Hermitian systems.

A scheme is proposed to enhance quantum correlation, including entanglement and steering, for two magnon modes in a cavity-magnon hybrid system through coherent quantum feedback. The hybrid system consists of a microwave cavity and two YIG spheres, which incorporates a nonlinear flux-driven Josephson parametric amplifier in order for the generation of two photons within the cavity simultaneously. A quantum coherent feedback loop is used for the reduction of effective dissipation. By modulating feedback parameters, optimal bipartite and tripartite entanglement, as well as quantum steering are derived. Importantly, compared with the same setup without coherent feedback, the proposed scheme significantly improves quantum correlation. Furthermore, by optimizing the feedback reflectivity and the ratio of cavity-magnon coupling strength, the enhancement of asymmetric steering can be controlled. Notably, incorporating the feedback loop effectively increase its robustness against thermal noise, thus the scheme offer better prospect for experimental development. This study paves the way for advancements in quantum information processing and quantum entanglement within cavity-magnonics.

Lead halide perovskite quantum dots (PeQDs) have garnered increasing attention due to their extraordinary optoelectronic properties. In recent years, femtosecond (fs) laser direct writing shows to be an effective way of inducing localized crystallization of PeQDs inside glass matrix while remaining their structural stability and optical performance. This article reviews the research progress on fs laser irradiation-induced nucleation/growth of PeQDs in glass and discusses the latest advancements in the use of the technology for optical data storage, micrometer-scale light-emitting diode (LED), information security protection, and other related fields. It offers novel insights and perspectives for exploring new functionality and device application of fs laser-printed PeQDs glass composite structures.

1D models with topological non-trivial band structures are a simple and effective way to study novel and exciting concepts in topological photonics. In this work, the propagation of light-matter quasi-particles, so-called exciton-polaritons, is studied in waveguide arrays. Specifically, topological states are being investigated at the interface between dimer chains, characterized by a non-zero winding number. In order to exercise precise control over the polariton propagation, non-resonant laser excitation, as well as resonant excitation, are studied in transmission geometry. The results highlight a new platform for the study of quantum fluids of light and non-linear optical propagation effects in coupled semiconductor waveguides.