Annalen der Physik最新文献

The photophysical properties of three carbazolyl phosphorescent molecules with similar structures-5-(9H-carbazole-9-group) nicotinitrile (P35N), 5-(9H-carbazole-9-group) nicotinamide (P35M) and 2-(9H-carbazole-9-group) isonicotinamide (P25M)-are investigated theoretically. The influence on luminescence is primarily elucidated through an analysis of geometry, electronic structure, and the dynamic processes occurring within the excited state. Structural analysis indicates that P35M exhibits the most effective luminescence due to minimal structural changes, reduced separation between the electron and hole, and enhanced intermolecular interactions within the crystal. Excited state dynamics and recombination energy analysis indicate that the higher triplet exciton population in the P35M molecule contributes to its long-lived phosphorescence. Furthermore, the intersystem crossing process for the three molecules is predominantly governed by low-frequency torsional rotation, while bond stretching vibrations are the primary factor leading to the inactivation of non-radiative processes. The distinct vibrational channels associated with reverse intersystem crossing and non-radiative processes present opportunities for further enhancement of the phosphorescent characteristics of these molecules.

Metasurfaces, known as planar two-dimensional (2D) metamaterials, are proposed to overcome obstacles like high loss and bulky volume occurring with three-dimensional (3D)metamaterials. Single-layer structures face limited degrees of freedom, and cannot satisfy the growing functional demands for meta-devices. To simplify the design process and gain more controllability, quasi-2D structures are introduced into metasurfaces in the form of stacked meta-atoms design or spatially cascaded metasurfaces. These configurations greatly expand the manipulation capability of metasurfaces and spawn a variety of functions and applications. In this review, the progress of metasurfaces with multi-layer stacked meta-atoms and spatially cascaded metasurfaces is presented. Progress is presented from metasurfaces with multi-layer stacked meta-atom configurations to spatially cascaded metasurfaces, focusing on the development of versatile applications for these quasi-2D configurations. Special attentions are paid to the diffractive deep neural networks(D²NNs), and a category of recently developed cascaded metasurfaces introduces a brand-new method into metasurface inverse designing as well as paves paths to all-optical computing. Finally, the promising avenues for such metasurfaces are discussed.

With the help of the Annalen der Physik, we can trace the young Einstein's footsteps in Italy in various ways: the interest in the topic of his first article on capillarity probably dates back to an earlier meeting with Carlo Marangoni in Casteggio; Einstein's reading of articles by Paul Drude and Wilhelm Wien allow us to identify the library of the Lombard Institute, Milan's Academy of Sciences and Letters, where the young man is working on his bibliography; this bibliography provides elements for a better understanding of the turnaround of his thesis, in mid-April 1901, on molecular forces in gases; and finally we see Einstein use his papers in the Annalen in his search for university posts, in connection with Giuseppe Jung, Michele Besso's uncle.

Degenerate Higher Order Scalar Tensor (DHOST) theories are the most general scalar-tensor theories whose Lagrangian depends on the metric tensor and a single scalar field and its derivatives up to second order. They propagate only one scalar degree of freedom, without being plagued by Ostrogradsky instabilities. This is achieved through certain degeneracies of the functions forming their Lagrangian. They generalize the Horndeski and beyond-Horndeski theories. Originally proposed to describe the late-time acceleration of the expansion of the universe, generalizing the cosmological constant, they can also be used to build models of the early universe, to describe inflation or alternatives to standard inflation. In the late universe, they modify the standard Vainstein screening mechanism from Horndeski theories (which can have observable consequences) and are suited to build black hole models, featuring non-stealth Kerr black hole solutions. In this work, their phenomenology is reviewed, looking at their basic properties, their parameterizations and classifications, focusing on solutions in the early and the late universe and at cosmological and astrophysical constraints.

Various characteristic structures, with no long-range spatial order, have often been observed in studies on the structural formation of soft materials. The order parameters, used to date, are not promising for computer detection of these types of structures. In this previous study, it is shown that machine-learning analysis using convolutional neural networks is very effective for the structural formation of spherical colloidal particles. This method is applied to non-spherical inverse patchy colloids and demonstrated that this order-parameter-free analysis method is effective for non-spherical soft matter, which often exhibits complex structures. A recent development in the structural formation of colloidal particle systems corresponds to the problem of monolayers of core-corona particle systems that exhibit a variety of structures. Monte Carlo simulations are performed for core-corona particles, confined between parallel plates, to clarify the conditions for the appearance of the bilayer and its in-plane structure formation. Parameter-free analysis is performed using image-based machine learning. The bilayer formation of the Jagla fluids is performed, and the phase diagram is clarified.

The paper introduces the concept of interferometric quantum teleportation. Based on this concept, a quantum secure communication (QSC) protocol, operating in a single-photon regime is proposed. The proposed protocol is characterized with higher efficiency and data rate than its original counterpart, namely, the teleportation-based quantum secure communication (T-QSC). The proposal is verified to be secure. Its security relies on both quantum (polarization of qubits) and relativistic (speed of light) restrictions. The relativistic restriction is possible due to the use of an interferometric quantum channel, like the relativistic quantum key distribution.

Self-Organizing Trivalent Spin Network

Spin dynamics in a Loop Quantum Gravity model with self-organized criticality leads to avalanches. Employing ergodic concepts, a perimeter–entropy relation is derived for the dimensionally reduced black hole. This entropy originates from the excitation–relaxation spin dynamics during avalanche cycles. For further details, see article number 2400109 by Christine C. Dantas.

Rogue waves (RWs) are mysterious nonlinear waves and have attracted much attention in recent years. However, they are usually unstable during propagation. Here, a scheme for stabilizing and guiding optical RWs in a cold atomic gas working under the condition of electromagnetically induced transparency is presented. It is shown that an external potential for probe laser field can be created by using an assisting laser field. If the assisting laser field has the form of Gaussian beam, the instability of the RWs can be largely suppressed. It is also shown that the RWs can be stabilized and guided to propagate along curved trajectories if the assisting laser field has the form of Airy beam. The results reported here contribute to the effort for stabilizing and manipulating RWs, which may have potential applications in optical transmission and information processing.

This study primarily focuses on exploring the nature of anisotropic spheres within the framework of extended symmetric teleparallel gravity. To accomplish this, an anisotropic matter distribution for $��f�(�Q�,�T�)�$ gravity model with Tolman–Kuchowicz spacetime is considered. Through this analysis, the necessary conditions for matching the interior and exterior geometries of the spheres are discussed and calculated the values of the unknown parameters involved. Furthermore, the physical properties of these spheres are analyzed using observational data from compact objects. The results demonstrate that the interior solutions obtained for anisotropic spheres fulfill all requisite physical criteria, thereby ensuring the stability of our model.