Plasmas in space and astrophysical systems exhibit complex motions that are strongly influenced by magnetic fields and that involve structures on various length scales. Comparing the observed behavior and computer simulations, this Colloquium interprets these turbulent motions in terms of relevant time scales, magnetic-field anisotropies, and competition between local nonlinear distortions and broad sweeping-type motions associated with wave propagation.

Nuclear magnetic resonance provides an important proving ground for quantum information processing. It has been the experimental workhorse for realizing quantum protocols, allowing the manipulation of systems up to seven qubits in size. This article presents the techniques employed, emphasizing the crucial elements of pulse control.

Magnetically confined plasmas, exemplified by the tokamaks and stellarators of fusion energy research, are now largely understood by Hamiltonian dynamics within toroidal geometries. This article is intended as a physicist's primer to the subject, explaining the fundamental concepts for describing these plasmas and designing their containing fields.

Gamma-ray bursts are thought to be triggered by stellar collapses in galaxies at cosmological distances, although the specific mechanisms have not yet been clearly identified. However, as discussed in this article, much of their phenomenology can be explained in terms of a single model: a beamed relativistic explosion that drives a shock wave into surrounding gas, but also possesses enough internal irregularity to drive relativistic shocks within the outflow itself.

The study of decoherence in quantum systems is important for a range of foundational and practical issues. Decoherence has, in particular, been proposed as a “solution” to the measurement problem in quantum mechanics, leading to lively debate about its significance for the interpretation of quantum mechanics. This article reviews the conceptual basis of the decoherence program and its links to various aspects of quantum theory and other approaches to measurements.