Abstract The next decade will feature an abundance of novel cosmological data, while many fundamental questions about inflation remain. Given this, there is ample need for maximally efficient calculations, especially in non-standard scenarios the early Universe. In inflationary cosmology, observables are computed within framework in-in perturbation theory. Weinberg introduced a now-widely used ...

Excitation energies for 2l23l8 hole-particle states of Ne-like ions are determined to second order in relativistic many-body perturbation theory ~MBPT!. Reduced matrix elements, line strengths, and transition rates are calculated for electric-dipole (E1), magnetic-quadrupole (E2), magnetic-dipole (M1), and magneticquadrupole (M2) transitions in Ne-like ions with nuclear charges ranging from Z51...

We analyze the echo dynamics in quasi-one-dimensional random media to investigate how the transition from localization to delocalization is encoded in its temporal decay properties. Our analysis extends from the standard perturbative regime corresponding to small perturbations (with respect to the mean level spacing) in the echo dynamics, out to the Wigner decay regime. On the theoretical side,...