The European Physical Journal B最新文献

In this work, we perform a detailed theoretical investigation into the electronic interactions governing protein–RNA complexes by employing a tight-binding Hamiltonian framework coupled by Green’s function methods. The RNA molecule is represented as a half-ladder network of nitrogenous bases, allowing us to evaluate three different protein structural conformations while assessing how multiple contact sites and fluctuating hopping integrals influence the system’s electronic behavior. To capture coherent electronic phenomena and suppress thermal broadening artifacts, we calculate the energy band structures (BS) and density of states (DOS) at low temperatures. Furthermore, both uniform and random configurations of hopping parameters are introduced within the RNA framework to simulate sequence diversity and structural variations. Our numerical findings demonstrate that protein–RNA binding induces notable energy level shifts and reorganizes the DOS profiles, where the intensity and location of these spectral modifications are dictated by the number of interface points, the specific protein shape, and the magnitude of the hopping links. This research emphasizes the crucial role of backbone coupling and outlines the overarching patterns of protein-induced electron delocalization along the RNA strand. Although the selected parameter sets and the low-temperature environment act as conceptual models rather than exact physiological duplicates, they offer meaningful perspectives on the underlying electronic features of these biomolecular assemblies. Ultimately, this theoretical approach establishes a robust basis for interpreting the qualitative electronic responses of biological systems, charting a path for subsequent models that integrate ambient environmental noise, base-to-base interactions, and direct empirical testing.

This research utilizes a mean field theory (MFT) on spin-1/2 diatomic molecules for the first time to obtain the thermal changes in magnetizations for each molecule, thus generating the phase diagrams. The same model was also studied using the Bethe lattice (BL) approach in terms of the exact recursion relations (ERR) in order to compare its results with the MFT results. Different types of bilinear interaction parameters between the constituents of a molecule and nearest-neighbor (NN) molecules were assumed, and the coordination number is set to three, corresponding to the honeycomb lattice. It is found that the MFT only gives second-order phase transitions, but the ERR approach gives various phase transitions. The obtained results show that the ERR approach on the BL is superior over the MFT since it provides many more details of the model.

We study opinion formation in a society where agents interact on a modular network generated using a stochastic block model (SBM). Opinion dynamics is modelled through the Biswas–Chatterjee–Sen (BChS) kinetic exchange model, in which agents undergo pairwise interactions that could be positive or negative. By tuning the relative strength of intra- and inter-group connectivity inherent to the SBM, as well as the disagreement probability, we identify distinct collective phases. In particular, we observe a robust regime with strong intra-group ordering but no global consensus, in addition to fully ordered and disordered states. In the particular case of two modules, we observe an anti-ferromagnetic type ordering with the increase of negative interaction between the groups. We investigate these ordering regimes using approximate analytical calculations and numerical simulations. These results demonstrate how modular interaction structure can qualitatively alter collective opinion dynamics and hinder consensus formation.

To account for the inhomogeneity of optical fiber media, we investigate a variable-coefficient Kundu–Eckhaus equation for optical pulse propagation. Under the integrable coefficient constraints, dark one-, two-, and three-soliton solutions are derived by means of gauge transformation and Hirota bilinear method. The results show that the variable coefficient r(x) mainly modulates the soliton trajectories, while both overtaking and head-on collisions of dark solitons remain elastic.

Inhomogeneous optical fibers are described by a variable-coefficient Kundu–Eckhaus equation. Via gauge transformation and Hirota bilinear method, we derive dark one-, two- and three-soliton solutions. The dispersion coefficient r(x) modulates soliton trajectories without altering intrinsic soliton profiles. Both overtaking and head-on collisions of dark solitons are elastic under integrable coefficient constraints

We develop a polylogarithmic structure for Bragg diffraction based on a weighted multi-plane interference model. Within this kind of construction, the scattering amplitude is expressed as a polylogarithmic generating function. By introducing extra contributions with power-law and the usual exponential decay, it takes the form (F(q) = textrm{Li}_mleft( e^{i qd - epsilon }right) ), where (epsilon ) is a finite coherence length. In the infinite-coherence limit, Bragg enhancement is associated with the approach of the polylogarithmic argument to its boundary singular point (z=1). This formulation provides a compact analytical framework for describing diffraction line shapes within a generalized correlation model in which peak positions, widths, and line shapes arise from a single analytic structure. Although we are able to recover the standard Bragg law for ideal crystals, the polylogarithm model captures deviations due to finite correlation length, disorder and non-uniform lattice coherence. We show that if Bragg peaks correspond to boundary singularities of the polylogarithm, a connection between diffraction theory and complex analysis arises. The proposed theoretical model may be particularly relevant for disordered or partially coherent materials, where conventional diffraction models often require additional phenomenological broadening assumptions.

A person opens their news feed and finds, in rapid succession, a story that inspires hope and another that provokes outrage. This alternation between contradictory emotional valences is the ordinary texture of contemporary media environments. What are the long-term consequences of such contradictory stimulation on an individual’s core affective state—the continuous background feeling of being comfortable or uncomfortable, well or unwell, that colours all emotional experience? Could the long-term consequences depend less on the content of any single message than on the statistical structure of the stream’s inconsistency? We capture this structure in a minimal stochastic model that treats the strength of external influence as a fluctuating parameter, yielding a stochastic differential equation with multiplicative noise. Its stationary distribution reveals two regimes that defy straightforward intuition. Intense contradiction does not amplify engagement but instead drives the affective state toward neutrality—a form of apathy in which sustained affect is suppressed altogether; exact neutrality occurs only when the default bias vanishes. Conversely, moderate contradiction with strong influence produces bimodal affective instability, with random alternation between two well-separated emotional states that arise from intra-individual dynamics rather than social polarization. A systematic mapping of the parameter space reveals a region of robust bimodality for low regulatory capacity and a region of enhanced fragility for near-neutral default bias. We offer this model as a preliminary exploration rather than a definitive account, and we hope its analytical transparency will invite empirical testing and further theoretical development.