We report multipronged progress on the stochastic averaging approach to numerical
analytic continuation of imaginary-time correlation functions computed by quantum Monte …

An overview of one-and two-dimensional quantum spin systems based on transition-metal
oxides and halides of current interest is given, such as spin-Peierls, spin-dimer …

We investigate weakly coupled spin-1/2 ladders in a magnetic field. The work is motivated
by recent experiments on the compound (C 5 H 12 N) 2 CuBr 4 (BPCB). We use a …

For many-particle systems defined on lattices we investigate the global structure of effective
Hamiltonians and observables obtained by means of a suitable basis transformation. We …

Magnetic excitations in the quasi-one-dimensional antiferromagnet IPA-CuCl 3 are studied
by cold neutron inelastic scattering. Strongly dispersive gap excitations are observed …

Phonon-assisted two-magnon absorption is studied in the spin-1/2 two-leg ladders of (Ca,
La) 14 Cu 24 O 41 for E∥ c (legs) and E∥ a (rungs). We verify the theoretically predicted …

We present a new linked cluster expansion for calculating properties of multiparticle
excitation spectra to high orders. We use it to obtain the two-particle spectra for systems of …

Spectral densities are computed in unprecedented detail for quantum antiferromagnetic spin
1/2 two-leg ladders. These results were obtained due to a major methodical advance …

The magnetic excitation spectrum in the bilayer iridate Sr 3 Ir 2 O 7 has been investigated
using high-resolution resonant inelastic x-ray scattering (RIXS) performed at the iridium L 3 …

We analyze the stability of the spontaneously dimerized phase of the frustrated Heisenberg
antiferromagnet—the J 1− J 2 model—in two dimensions. The lowest triplet excitation …