Annalen der Physik最新文献

There is no simple and universal analytical description of various micro-optical systems related with Fano resonances. This especially concerns modulated thin films, which, when coupled to external fields, show Fano resonances. Usually, such micro-optic schemes are simulated numerically, frequently by the use of commercial software. The study fills this gap of the lack of universal analytical description by introducing and exploring a simple mechanical equivalent, the oscillator chain, which mimics such schemes involving Fano resonances. The model does not necessarily provide the rigorous description of complicated micro-optical schemes, however does capture the main properties of such Fano-related micro-optical systems. The model captures different modifications of the thin film arrangement as well: thin film with amplification, non-Hermitical thin films, and others. It also covers the case of multiple Fano resonances in a thin film. The model is validated by comparing with the rigorously calculated wave propagation in the thin films.

Beam-splitters are basic and instrumental tools not only in the study of foundational issues in quantum mechanics, but also in various applications of quantum information processing. In the continuous-variable scenario involving quantum optical states and Gaussian quantum information, interference phenomena are widely investigated and characterized via beam-splitters. In this work, within the framework of stabilizer quantum computation in finite quantum systems, entanglement and magic correlations generated by discrete beam-splitters are explored. Two types of magic correlations are distinguished: mutual magic (analogous to quantum mutual information) and non-local magic. Explicit formulas for these correlations are derived in the qubit scenario where the beam-splitter is implemented by the controlled-NOT gate, with the $�H$-type magic states playing a particularly prominent role as input states. Extending to prime-dimensional qudit systems, it is shown that fiducial states of mutually unbiased bases also play a remarkable role. Basic properties of these magic correlations are revealed and illustrated through some typical examples.

This research investigates the dynamics of entanglement and uncertainty-induced nonlocality (UIN) in a spin-1/2 Ising-Heisenberg diamond chain subjected to local non-Markovian decoherence channels. By examining amplitude damping (AD) and random telegraph noise (RTN) in both zero and finite temperature regimes, the study reveals nuanced distinctions in the degradation and revival of quantum correlations. The interplay between intrinsic spin couplings, thermal effects, and memory-induced coherence backflow highlights the complex behavior of quantum resources under realistic noise conditions. Concurrence emerges as a sensitive marker of entanglement recovery in dephasing environments, while uncertainty-induced nonlocality proves more resilient in high-temperature or dissipative regimes. The analysis further demonstrates that moderate thermal activation and external magnetic fields can nontrivially enhance or suppress quantum features depending on system parameters. These findings offer a detailed perspective on the robustness and complementarity of different quantum correlation measures, providing guiding principles for the design of thermally stable and noise-resilient quantum information protocols.

Condensation stagnation, that is, the existence of a delay between nucleation and growth during gas-phase particle formation, is a crucial phenomenon that affects associated processes and manifests itself as the presence of supercritical clusters in resulting particulates. In previous work, this unique phenomenon was experimentally demonstrated in a magnesium (Mg) particle flame, and an empirical explanation for the mechanisms responsible for the phenomenon was provided. The occurrence of stagnant clusters was revealed using specially designed sampling. The analysis of collected products, however, could not provide details about their evolution, so no information on the cluster's lifespan (i.e., stagnation time) was available. In the current manuscript, the results of spectroscopic studies of the Mg particle flame in air are reported. The recently developed advanced processing analysis of pyrometry data makes it possible to identify the light emission signature of stagnant clusters and, accordingly, estimate their lifespan, that is, the time during which clusters have physical properties (e.g., emissivity) different from those of mature nano-oxides. The obtained time on the order of 10 ms seems to be sufficiently long, which allows one to consider stagnant clusters as a separate state of matter, and not as a metastable metal oxide material.

This research investigates the entanglement properties of multipartite GHZ states of bosonic and fermionic fields, particularly in scenarios where some parties are uniformly accelerated. The analysis incorporates perspectives from both inertial and non-inertial observers. Entanglement is quantified using the Π-tangle for GHZ states and the one-tangle for multipartite GHZ states. To facilitate this analysis, the study derives the density matrices for the multipartite GHZ states with m uniformly accelerated parties (). The results reveal that entanglement diminishes as the acceleration parameter increases, with accelerated observers experiencing less entanglement compared to their inertial counterparts. In the bosonic case, genuine entanglement is entirely lost for non-inertial observers at high accelerations, whereas inertial observers still experience it. In the fermionic case, however, genuine entanglement is not completely eliminated when the number of accelerated parties is limited. Furthermore, the decrease in entanglement is proportional to the number of accelerated parties, approaching zero as m tends to infinity ($��m�\to �\infty �$).

With advances in device miniaturization, understanding and manipulating nanoscale hot electron dynamics in semiconductors is recognized as an essential factor for improving performance and energy efficiency in optoelectronics and logic devices in the post-Moore era. This work demonstrates an effective strategy to modulate hot electron dynamics through nonequilibrium phonon excitations, utilizing first-principles-based mode-resolved electron-phonon coupled Boltzmann transport equation calculations. Two different phonon-mediated pathways for perturbing hot electron relaxation dynamics in doped semiconductors are illustrated, i.e., high-frequency optical phonons (e.g., longitudinal optical phonons in GaN) and low-frequency acoustic phonons, both of which exhibit strong coupling with electrons. While exciting high-frequency optical phonons to significant nonequilibrium states can quickly reheat and elevate electron temperatures, their rapid energy decay to other phonons fails to continuously slow down the subsequent hot electron relaxation. In contrast, the weak coupling of low-frequency acoustic phonons with other phonons facilitates the excitation of long-lived phonon nonequilibrium, which effectively prolongs the hot electron relaxation process from a few to tens of picoseconds for GaN, AlN, and Si. These findings reveal a general mechanism to modulate hot electron dynamics in device semiconductors, offering promising approaches to enhance the energy efficiency of advanced nanoscale devices.

The effect of structural disorder on the electrical transport is systematically studied in Bi₂Se₃-Fe₃O₄ nanograin-bulk thermoelectric materials. Keeping the characteristics of the Bi₂Se₃ matrix under control allows to evidence the role of localization and surface interaction in electronic transport in bulk nanostructured thermoelectric composites. Nanograin Bi₂Se₃-Fe₃O₄ bulks present an enhanced thermoelectric performance compared to Bi₂Se₃ and enable the realization of linear magnetoconductance at low temperatures in composite bulks. With the addition of Fe₃O₄, a crossover from positive to negative magnetoconductance is realized, more enhanced in c-axis textured samples. The observations are compatible with the presence of high mobility carriers at the Bi₂Se₃-Fe₃O₄ interfaces of the material.

The Gödel universe is considered within the context of the local limit of nonlocal gravity. This theory differs from Einstein's general relativity (GR) through the existence of a scalar susceptibility function $��S�\left(�x�\right)�$ that is a characteristic feature of the gravitational field and vanishes in the GR limit. It is shown that Gödel's spacetime is a solution of the modified gravitational field equations provided $�S$ is a constant, in conformity with the spatial homogeneity of the Gödel universe.