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

We present an up-to-date survey of theoretical concepts and results in the field of one-
dimensional magnetism and of their relevance to experiments and real materials. Main …

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 …

The transition from dimerized to uniform phases is studied in terms of spectral weights for
spin chains using continuous unitary transformations. The spectral weights in the S= 1 …

The microscopic origins of emergent behaviours in condensed matter systems are encoded
in their excitations. In ordinary magnetic materials, single spin-flips give rise to collective …

Quasiparticle properties of quantum magnets with long-range interactions are investigated
by high-order linked-cluster expansions in the thermodynamic limit. It is established that …

A quantitative description of magnons in long-range ordered quantum antiferromagnets is
presented which is consistent from low to high energies. It is illustrated for the generic S= 1/2 …

A variational approach for constructing an effective particle description of the low-energy
physics of one-dimensional quantum spin chains is presented. Based on the matrix product …

Based on a two-dimensional model of coupled two-leg spin ladders, we derive a unified
picture of recent neutron scattering data of stripe-ordered L a 15/8 B a 1/8 C u O 4, namely …