Open quantum systems (OQSs) cannot always be described with the Markov approximation,
which requires a large separation of system and environment time scales. An overview is …

In the early 1970s, Wilson developed the concept of a fully nonperturbative renormalization
group transformation. When applied to the Kondo problem, this numerical renormalization …

Approaching the long-time dynamics of non-Markovian open quantum systems presents a
challenging task if the bath is strongly coupled. Recent proposals address this problem …

The dynamical convergence of a system to the thermal distribution, or Gibbs state, is a
standard assumption across all of the physical sciences. The Gibbs state is determined just …

Multicomponent quantum systems in strong interaction with their environment are receiving
increasing attention due to their importance in a variety of contexts, ranging from solid state …

This Perspective presents an overview of the development of the hierarchy of Davydov's
Ansätze and a few of their applications in many-body problems in computational chemical …

By using the properties of orthogonal polynomials, we present an exact unitary
transformation that maps the Hamiltonian of a quantum system coupled linearly to a …

Quantum systems are invariably open, evolving under surrounding influences rather than in
isolation. Standard open quantum system methods eliminate all information on the …

Multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) theory is a rigorous and
powerful method to simulate quantum dynamics in complex many-body systems. This …

A simple and very flexible variational approach to the out-of-equilibrium quantum dynamics
in strongly correlated electron systems is introduced through a time-dependent Gutzwiller …