Annalen der Physik最新文献

A simplified three-rate-equation model is proposed to study the dynamic behavior of a two-section high-power tapered laser. The model includes a traveling intensity approach to calculate the photon ratios in both sections. The simulations align with the experimental data of a 1060 nm distributed Bragg reflector two-section tapered laser. The effect of driving conditions is analyzed on the peak power and pulse duration. The pulses it obtain experimentally are ≈100 ps with 4.2 W peak power at a 900 MHz repetition rate.

The interaction between two Airy pulses propagating at different wavelengths is numerically investigated. The periodically varying peak intensity of the soliton that emerges from stronger Airy pulse (pump pulse) leads to the formation of periodic temporal boundary. The relatively weaker Airy pulse (probe pulse) on interaction with this boundary gets partially reflected as well as transmitted. As a result, the probe pulse spectrum splits into two parts- the reflected pulse spectrum undergoes redshift while transmitted pulse exhibits blueshift. The probe pulse witnesses maximum reflection when point of interaction lies on the intensity maxima of the emergent soliton from pump Airy pulse. On the other hand, maximum transmission occurs when probe Airy pulse interacts at the intensity minima of the soliton. The reflection and transmission processes can be manipulated by tuning the time delay between pump and probe Airy pulses. In the case of a sufficiently intense pump pulse, the temporal boundary mimics the artificial optical event horizon, and the weak probe Airy pulse is completely reflected. This phenomenon is equivalent to the temporal version of total internal reflection. The results of the study hold potential applications in optical manipulation and temporal waveguiding.

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.