Annalen der Physik最新文献

Research into network dynamics of spreading processes typically employs both discrete and continuous time methodologies. Although each approach offers distinct insights, integrating them can be challenging, particularly when maintaining coherence across different time scales. This review focuses on the Microscopic Markov Chain Approach (MMCA), a probabilistic f ramework originally designed for epidemic modeling. MMCA uses discrete dynamics to compute the probabilities of individuals transitioning between epidemiological states. By treating each time step—usually a day—as a discrete event, the approach captures multiple concurrent changes within this time frame. The approach allows to estimate the likelihood of individuals or populations being in specific states, which correspond to distinct epidemiological compartments. This review synthesizes key findings from the application of this approach, providing a comprehensive overview of its utility in understanding epidemic spread.

In this review, the thermoelectric properties in nodal-point semimetals with two bands are discussed. For the two-dimensional (2D) cases, it is shown that the expressions of the thermoelectric coefficients take different values depending on the nature of the scattering mechanism responsible for transport, by considering examples of short-ranged disorder potential and screened charged impurities. An anisotropy in the energy dispersion spectrum invariably affects the thermopower quite significantly, as illustrated by the results for a node of semi-Dirac semimetal and a single valley of graphene. The scenario when a magnetic field of magnitude $�B$ is applied perpendicular to the plane of the 2D semimetal is also considered. The computations for the three-dimensional (3D) cases necessarily involve the inclusion of nontrivial Berry phase effects. In addition to demonstrating the expressions for the response tensors, the exotic behavior observed in planar Hall and planar thermal Hall set-ups is discussed.

In this work, two new embedded WH solutions are obtained by using the Class-I approach in the background of newly fourth-order Ricci inverse gravity. It is shown that the combination of these newly calculated shape functions and Ricci inverse gravity provides us with the possibility of obtaining traversable wormholes. All the required wormhole properties are discussed, along with flaring out and flatness conditions. The embedded diagrams within the scope of upper and lower universes are provided under the effect of both newly calculated embedded shape functions. All the energy conditions are explored with valid and negative regions. The presence of exotic matter is confirmed due to the negative region in all the energy conditions, specifically in the null energy condition. The Doppler effect through the red-blue shifts function is also discussed. Several key findings from the current research are described that demonstrate the validity of these wormhole solutions in Ricci inverse gravity.

In the nonequilibrium steady state of electronic transport across a spin-resolved quantronic junction, the role of cotunneling on the emergent statistics under phase-different adiabatic modulation of the reservoirs' chemical potentials is investigated. By explicitly identifying the sequential and inelastic cotunneling rates, the geometric or Pancharatnam–Berry contribution to the spin exchange flux between the spin system and the right reservoir is numerically evaluated. The relevant conditions wherein the sequential and cotunneling processes compete and selectively influence the total geometric flux upshot are identified. The Fock space coherences are found to suppress the cotunneling effects when the system reservoir couplings are comparable. The cotunneling contribution to the total geometric flux can be made comparable to the sequential contribution by creating a right-sided asymmetrically stronger system-reservoir coupling strength. Using a recently proposed geometric thermodynamic uncertainty relationship, the total rate of minimal entropy production is estimated. The geometric flux and the minimum entropy is found to be nonlinear as a function of the interaction energy of the junctions' spin orbitals.

The analytical procedure is developed for the calculation of the quantum second-order autocorrelation function $�g_2$ of a small super-radiant LED, where the field, polarisation, and population of the active medium cannot be eliminated adiabatically. The Langevin force, which describes the effect of population fluctuations on the LED polarisation and preserves the operator commutation relations, is found. It is demonstrated that the super-thermal photon statistics with $��g_2�>�2�$ of a small quantum LED with large photon number fluctuations, emitter-field coupling, bad cavity, and operating in the limit $��n�\to �0�$, is the result of a combined effect of the spontaneous emission, collective effects and population fluctuations. Analytical expressions for $�g_2$ and $�n$ are derived.

Attention to Entropic Communication

Attention focuses limited cognitive resources on essential information and therefore plays a central role in natural and artificial intelligence. Relative attention entropy allows to focus approximate probability functions on their most relevant parts. In the top image, the attention guided approximation of a double peaked probability density by a Gaussian focuses on the more relevant peak. Bottom: Attention emerges as importance-weighted probability in utility-conscious communication. For further information, see article number 2300334 by Torsten Enßlin and co-workers

Light diffraction is studied numerically and experimentally on a double fork-shaped grating representing a periodic grating containing two spaced dislocations. The spatial dynamics of the phase singularities (optical vortices) has been investigated as a function of dislocation parameters. Produced optical vortices affect each other while propagating in a free space. For dislocations of the same topological charge, the propagation trajectories and their transverse displacement coordinates depend on the dislocation spacing, and the larger the dislocation spacing, the smaller the relative displacement of the optical vortices and the smaller their trajectory curvatures. For oppositely charged dislocations, three types of spatial behavior of optical vortices are found. The numerical results agree well with the experimental data.