The European Physical Journal Plus最新文献

We present a quantum sensing protocol for the simultaneous estimation of the difference in the localization parameters of two single-photon sources, paving the way to single-photon 3D imaging and 3D nanoscopy beyond the diffraction limit. This is achieved by exploiting two-photon interference of the two emitted photons at a beam splitter via sampling measurements in the frequency and transverse momenta at the output. We prove theoretically that this technique reaches the ultimate sensitivity in the 3D relative localization of two emitters, already with a number of sampling measurements of (sim 2000) and a bias in the three localization parameters below (1%). These results are independent of the values of the localization parameters to estimate.

We analyze a quantum particle in the modified trigonometric inversely quadratic (MTIQ) potential—a pseudoharmonic well with a repulsive inverse-square core. Using the formula method, we derive bound-state energies and normalized wavefunctions; momentum-space states are obtained via a Fourier transform. We then evaluate Shannon information entropies in position and momentum space for representative states and analyze their dependence on quantum numbers and potential parameters. Increasing n (at fixed l) broadens both position and momentum densities, so information entropies in position and momentum space increase, and their sum satisfies the Białynicki–Birula–Mycielski (BBM) bound in all cases considered. Finally, we derive thermodynamic functions from the discrete spectrum using a Poisson-summation representation of the partition function and discuss the crossover from a gap-dominated low-temperature regime to an effectively harmonic high-temperature regime. We also summarize the stability condition associated with the inverse-square core.

The investigation of group defense phenomena in prey–predator models is of significant ecological importance because defensive behaviors can substantially influence the population stability and ecosystem resilience. Thus, we investigate the impact of group defense mechanism in a prey-predator model in the context of Smith-type growth in prey and intraspecies competition among predators to understand the deeper insights of complex dynamics. Smith growth dynamics is incorporated to examine the impact of resource limitation or crowding effect and toxicant environment on prey species. The model exhibits rich dynamics, including the existence of multiple interior equilibrium points and bifurcations, which enhances the level of complexity in the model. To examine the local behavior of the model in the vicinity of the equilibrium points, we have conducted a local stability study. Subsequently, we explore the study of both codimension-one and codimension-two bifurcations to demonstrate the behavioral transition of the model due to the variations of some sensitive parameters. Thus, we analyze the dynamical changes in the model where the system exhibits some major bifurcations including transcritical, Hopf, generalized Hopf, saddle-node, Bogdanov–Takens, and cusp bifurcations with respect to the parameter responsible for group defense phenomena. Various threshold values of the corresponding parameters are derived regarding these bifurcations to determine qualitative changes in the ecosystem. Our study indicates that the stronger crowding effect employs a stabilizing impact on the dynamics. One notable ecological observation is that the model exhibits bubbling phenomena in the context of intraspecies competition, indicating the transition of stable coexistence to oscillatory dynamics. Finally, numerical simulations are performed for the dynamical model to validate theoretical studies, which comprise sensitivity analysis of the parameters, some graphical illustrations, and numerical computations.

Ethnophysics arises from the desire to uncover the physics underlying various customs and local wisdoms that have been practiced for generations by certain communities. Additionally, physics concepts and mathematics can be used to shed light on the dynamics of these local wisdoms. In this study, the phenomena of ritual shifts in Ngino Village were analysed via the lattice gas model in two dimensions (2D) by generating network mappings. The rituals in Ngino Village consisted of Mubeng Ringin, Nenepi, and Merti Desa. This theoretical study was conducted by establishing a correspondence between two mathematical models, namely the asymmetric simple exclusion process (ASEP) and the static equilibrium hard-core model. A second correspondence was established between the latter model and the Ngino Village rituals. The results of this correspondence showed network mapping density profiles of the ritual shifts of people in various age groups as particles caused by new activities in Ngino Village as external potentials. The Mubeng Ringin, Nenepi, and Merti Desa rituals demonstrated shifts in the network mapping density profiles caused by attractive potentials of career/occupation, religious and educational, and leisure and trade activities, respectively. The results of this study are valuable as considerations for the study and evaluation of government policies in efforts to preserve local cultures.

The problem of solving the electric potential and equivalent resistance for circuit network has been an important research topic for many years. However, some resistor networks with special structures have not been studied, such as the quasi globe network (QGN). This article uses RT-I (Recursion-Transform based on current parameters) theory to study the electrical properties of a class of m × n QGN, achieving new research progress. The analytical expressions for its potential function and equivalent resistance between any two nodes are given, and 3D visualization was carried out to intuitively reveal the changes in their electrical characteristics. The RT-I theory consists of five steps, with the main steps being the establishment and solution of matrix equations, and the key issue being the construction of matrix transformations and inverse transformations, this article has made new research results in this problem. The results can provide a theoretical tool for researchers to analyze and study LC networks and fractional circuit networks, and provides a theoretical foundation for related engineering applications and fast algorithms for potential functions.

In this work, we study a codimension-one thick brane in modified symmetric teleparallel gravity for the specific additive ansatz (f(Q,mathcal {T}) = Q + k_{1} Q^{n} + k_{2}mathcal {T}). Using two physically motivated warp factor, we construct the full brane system, derive background solutions, and analyze how nonmetricity corrections and the matter-trace coupling modify brane internal structure and graviton localization. For both warp profiles, we obtain the corresponding Schrödinger-like equation for tensor perturbations, identify conditions for volcano and multi-well effective potentials, and determine when a localized zero mode arises. We discuss the physical implications of our results, such as possible short-range corrections to Newton’s law and resonant Kaluza–Klein modes, and outline observational prospects and directions for future work.

To satisfy the high-performance and wide-bandwidth filtering requirements of optical communication systems, this work presents a broadband dual-window in-fiber polarization filter based on gold layer deposited photonic crystal fiber (PCF), using finite element method. There are two coupling mechanisms in this device. This allows the bandwidth to cover two communication windows of 1.31 and 1.55 μm, while simultaneously featuring high filtering capabilities. The numerical results indicate that when the appropriate structural parameters are determined, two SPR coupling mechanisms will occur within the proposed PCF, which is beneficial for the gold-deposited PCF to achieve superior filtering performance. The 1-mm-long all-fiber filter possesses the maximum extinction ratios (ERs) of − 46.7 dB at 1.31 μm and − 55.1 dB at 1.55 μm, with an operating bandwidth of  > 820 nm (> 1.28 μm) in the investigated band. Additionally, the PCF filter has ease of manufacture. This high-performance in-fiber filter is anticipated to play a significant role in modern communication networks, including multiplexing/demultiplexing, wavelength selection, optical add-drop multiplexing, and fully optical signal processing at network nodes.

We investigate the impact of extended inhomogeneities on the dynamics of nonlinear magnetic excitations (solitons) propagating in a single-ion anisotropic Heisenberg spin chain. The extended inhomogeneous domain consists of a set of neighboring spins with disruption of the exchange interaction and/or easy-axis anisotropy. To explore the dynamics of the magnetization, we derive the corresponding Schrödinger equation incorporating linear and nonlinear perturbative terms. While, in the case of a homogeneous chain with an easy-axis anisotropy, the ensuing equation possesses a bright soliton-like solution, an extended inhomogeneity in the spin coupling and/or the anisotropy leads to a physically rich behavior in the soliton dynamics. An inhomogeneous domain with enhanced exchange interaction induces a potential barrier that either transmits or reflects the incident soliton. On the other hand, a segment with reduced coupling brings about a potential well that for a given range of initial velocities and exchange interaction mismatch the scattering patterns exhibits periodic regions of transmissions and trapping as a function of the length of the inhomogeneous domain. The transmission is associated with an excitation and a subsequent resonant de-excitation of the soliton’s shape oscillations at the well boundaries. A thorough analysis shows that the oscillations emanate from the interference of the solitons with emitted spin waves. The interplay of the exchange interaction and single-ion anisotropy mismatch leads to unusual soliton dynamics promoting a complex potential profile in the inhomogeneous domain.

The dynamic complexity of chaotic systems is crucial for secure communication, yet balancing this with structural simplicity and robustness remains challenging. To address this, we propose two novel hyperchaotic maps built by coupling multiple discrete memristors in chain-type architectures via direct cascade and parameter-controlled methods. Key steps involve designing memristor-based nonlinear units and interconnecting them into a feedback-rich chain structure with tailored coupling parameters. Dynamical analysis shows these maps exhibit initial-boosted extreme multistability and high complexity. The parameter-controlled design demonstrates strong robustness, maintaining a spectral entropy above 0.85 under perturbations. Both are physically realized on digital hardware. In differential chaos shift keying tests, they outperform recent chaotic maps and the Logistic map in bit error rate and security. This work provides a robust, implementable framework for enhancing secure communication with chaotic systems.

In this work, we employed melt-quenching procedure to synthesize BaO- and Er₂O₃-doped bismuth-borate glasses to explore how varying BaO and Er₂O₃ affected their physical, structural, optical, and radiation shielding characteristics. Density and molar volume increased with higher BaO and Er₂O₃ due to replacing lighter B₂O₃ with heavier ions, which expanded the glass network through the creation of non-bridging oxygens. FTIR showed structural changes, with BO₄ units converting to BO₃ and disrupted borate networks from BaO addition. Optically, absorption from Er³⁺ intra-4f transitions intensified with more dopant, lowering transmittance and optical band gaps. The reduced band gap (3.031 to 2.863 eV for direct and 2.622 to 2.423 eV for indirect) and increased Urbach energy (0.260 to 0.301 eV) indicated more structural disorder and localized states. Refractive index and polarizability rose due to greater NBO formation. Due to Ba (Z = 56), Er (Z = 68), and Bi (Z = 83), all samples (20Ba0Er to 26Ba3Er) showed significant increases in G_MAC at photon energies around 2, 4, and 10 keV. At 0.015 MeV, 26Ba3Er had the highest G_MAC (66.937 cm²/g), lowest G_HVL (0.0020 cm), G_TVL (0.0067 cm), and shortest G_MFP (0.0029 cm), indicating excellent shielding. Increasing BaO and Er₂O₃ raised gamma attenuation by increasing density from 4.702 to 5.122 g/cm³. The 20Ba0Er sample, richest in B₂O₃ (65 mol%), had the highest neutron attenuation (Σ_R = 0.11274 cm⁻¹), while 26Ba3Er had the lowest (Σ_R = 0.11264 cm⁻¹). Thus, B₂O₃-rich glasses excel in thermal and fast neutron shielding, whereas in mixed radiation fields BaO- and Er₂O₃-rich glasses are better for gamma shielding.