Table of contents

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma-ray burst and its afterglow is reviewed.

Since the introduction of optical data storage systems in the 1970s, we have observed a stepwise increase in their storage capacity using the same means for resolution improvement as in classical microscopy and optical lithography, namely, a reduction in the source wavelength and an increase in the numerical aperture of the imaging optics. In this paper we briefly address the historical development of optical data storage and some recent developments towards higher density such as non-linear recording methods and systems with a numerical aperture larger than unity. More specifically, we explore the possibility of storing more information bits per storage location so that optical 'multiplexing' becomes feasible. A multiplexing method based on the detection of optical angular momentum of a focused light beam is treated in detail and is illustrated with some examples of preliminary experiments on this subject. Both the existing high-density systems and the proposed new ones require a detailed analysis of the focusing of the scanning spot and the diffraction by the information structure on the disc. We analyse electromagnetic focusing in multilayers and treat the diffraction of light by optical effects using a three-dimensional form of Green's tensor formalism.

Atomic-scale materials modelling based on first-principles quantum mechanics is playing an important role in the science of the Earth and the other planets. We outline the basic theory of this kind of modelling and explain how it can be applied in a variety of different ways to probe the thermodynamics, structure and transport properties of both solids and liquids under extreme conditions. After a summary of the density functional formulation of quantum mechanics and its practical implementation through pseudopotentials, we outline the simplest way of applying first-principles modelling, namely static zero-temperature calculations. We show how calculations of this kind can be compared with static compression experiments to demonstrate the accuracy of first-principles modelling at pressures reached in planetary interiors. Noting that virtually all problems concerning planetary interiors require an understanding of materials at high temperatures as well as high pressures, we then describe how first-principles lattice dynamics gives a powerful way of investigating solids at temperatures not too close to the melting line. We show how such calculations have contributed to important progress, including the recent discovery of the post-perovskite phase of MgSiO₃ in the D'' layer at the base of the Earth's mantle. A range of applications of first-principles molecular dynamics are then reviewed, including the properties of metallic hydrogen in Jupiter and Saturn, of water, ammonia and methane in Uranus and Neptune, and of oxides and silicates and solid and liquid iron and its alloys in the Earth's deep interior. Recognizing the importance of phase equilibria throughout the planetary sciences, we review recently developed techniques for the first-principles calculation of solid and liquid free energies, melting curves and chemical potentials of alloys. We show how such calculations have contributed to an improved understanding of the temperature distribution and the chemical composition throughout the Earth's interior. The review concludes with a summary of the present state of the field and with some ideas for future developments.

This review paper summarizes recent advances in the quickly developing field of nanoscale ferroelectrics, analyses its current status and considers potential future developments. The paper presents a brief survey of the fabrication methods of ferroelectric nanostructures and investigation of the size effects by means of scanning probe microscopy. One of the focuses of the review will be the study of kinetics of nanoscale ferroelectric switching in inhomogeneous electrical and elastic fields. Another emphasis will be made on tailoring the electrical and mechanical properties of ferroelectrics with a viewpoint of fabrication of nanoscale domain structures.

This article is an experimental review of the status and prospects of indirect searches for dark matter. Experiments observe secondary particles such as positrons, antiprotons, antideuterons, gamma-rays and neutrinos which could originate from annihilations of dark matter particles in various locations in the galaxy. Data exist from some experiments which have been interpreted as hints of evidence for dark matter. These data and their interpretations are reviewed together with the new experiments which are planned to resolve the puzzles and make new measurements which could give unambiguous results.