Journal Article

The heavy-quark contribution to the polarization function Π at higher perturbative orders is presently only known approximately. We scrutinize the accuracy of state-of-the-art approximations at three- and four-loop order [...]

The diffuse very high-energy (VHE; >100 GeV) γ-ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130 pc to the Galactic centre (GC), where the flux rapidly decreases [...]

A search for tau neutrino induced showers with the MAGIC telescopes is presented. The MAGIC telescopes located at an altitude of 2200 m a.s.l [...]

We systematically study the efficiency enhancement of high-harmonic generation (HHG) in an Ar gas cell up to the soft X-ray (SXR) range using a two-color laser field composed of 2.1 μm (ω) and 700 nm (3ω) with parallel linear polarization. Our experiment follows the recent theoretical investigations that determined two-color mid-infrared (IR) pulses, mixed with their third harmonic (ω + 3ω), to be close to optimal driving waveforms for enhancing HHG efficiency in the SXR region [Jin et al., Nature Comm. [...]

We present a combination of first-principles and experimental results regarding the structural and magnetic properties of olivine-type $\mathrm{LiFePO_{4}}$ under pressure. Our investigations indicate that the starting $Pbnm$ phase of $\mathrm{LiFePO_{4}}$ persists up to 70 GPa [...]

Abstract: A nitrogen-rich compound, ReN8·xN2, was synthesizedby a direct reaction between rhenium and nitrogen at highpressure and high temperature in a laser-heated diamond anvilcell. Single-crystal X-ray diffraction revealed that the crystalstructure, which is based on the ReN8 framework, hasrectangular-shaped channels that accommodate nitrogen molecules.Thus, despite a very high synthesis pressure, exceeding100 GPa, ReN8·xN2 is an inclusion compound. [...]

Ultrashort, high-intensity terahertz (THz) pulses, e.g., generated at free-electron laser facilities, allow for direct investigation as well as the driving of intermolecular modes in liquids like water and thus will deepen our understanding of the hydrogen bonding network. In this work, the temperature-jump (T-jump) of water induced by THz radiation is simulated for ten different THz frequencies in the range from 3 to 30 THz and five different pulse intensities in the range from 1 × 10$^{11}$ to 5 × 10$^{12}$ W/cm$^{2}$ employing both ab initio molecular dynamics (AIMD) and force field molecular dynamics (FFMD) approaches [...]

We demonstrate a high-power offset-free ultrafast mid-infrared (IR) laser source based on difference-frequency generation (DFG). Powerful signal pulses are obtained by filtering the rightmost spectral lobe of the optical spectra broadened by fiber-optic nonlinearities dominated by self-phase modulation. [...]

In this article we summarise our results from numerical simulations of $\mathcal{N}=1$ supersymmetric Yang-Mills theory with gauge group SU(3). We use the formulation of Curci and Veneziano with clover-improved Wilson fermions. [...]