Highlights of 2005

I am delighted to present a special collection of the very best articles published in Reports on Progress in Physics in 2005. Articles were selected by the Editorial Board for their outstanding reviews of the field. They all received the highest praise from our international referees and a high number of downloads from the journal Website.

These 12 articles are only a small sample of the wide range of content in Reports on Progress in Physics which publishes across the whole of physics, covering:

• astrophysics and cosmology
• atomic, molecular and optical physics
• condensed matter and materials
• earth sciences
• metrology
• soft condensed matter and biological physics
• nuclear physics
• particle physics

Articles are designed to be accessible to physicists working in the fields and form an ideal introduction to graduate students entering the subject.

Further journal information for readers, subscribers or authors can be found on the journal home page or you can e-mail the journal publishing team at rop@iop.org.

Richard Palmer, Publisher

PAPERS

77		The mass of the photon Liang-Cheng Tu, Jun Luo and George T Gillies 68 No 1 (January 2005) A nonzero photon rest mass would have far-reaching implications such as variation of the speed of light, deviations in static electromagnetic fields, longitudinal electromagnetic radiation, and even gravitational deflection. This review assesses the experimental methods that have set upper limits on the photon rest mass. As yet, there has been no firm finding of a finite photon mass, but ever more stringent upper bounds have been set. Abstract | References Full text: Acrobat PDF
201		The Casimir force: background, experiments, and applications Steven K Lamoreaux 68 No 1 (January 2005) The Casimir force - the attraction of two uncharged material bodies due to modification of the zero-point energy associated with the electromagnetic modes in the space between them – has recently been measured with percent-level accuracy. This article reviews the theory of the Casimir force and its corrections for real materials and finite temperature and discusses applications of the theory to a number of practical problems. Abstract | References Full text: Acrobat PDF
449		Physics of negative refractive index materials S Anantha Ramakrishna 68 No 2 (February 2005) It has been known for some time that a medium in which the relative dielectric permittivity and relative magnetic permeability are both negative will have a negative refractive index. There has recently been an explosion of interest in such materials, which have now been realized experimentally. Negative refractive index materials offer the possibility of a perfect lens that enables imaging with sub-wavelength image resolution. This article reviews the fundamental concepts and ideas of negative refractive index materials. Abstract | References Full text: Acrobat PDF
523		Electron tunnelling in self-assembled monolayers Wenyong Wang, Takhee Lee and Mark A Reed 68 No 3 (March 2005) There has been much recent interest in both the basic transport physics and potential technological applications of molecular electronics, but some reports of molecular mechanisms in electronic devices have turned out to be due to filamentary conduction. This article reviews the mechanisms and characterization methods of electronic transport through self-assembled monolayers (SAMs). Using SAMs of alkanethiols in a nanometer scale device structure, tunnelling is unambiguously demonstrated as the main intrinsic conduction mechanism for defect-free large bandgap SAMs. Abstract | References Full text: Acrobat PDF
855		The physics of snow crystals Kenneth G Libbrecht 68 No 4 (April 2005) This article reviews how snow crystals (snowflakes) grow from water vapor as an illustration of the more general physics of crystal growth. As crystals grow and develop, they create complex structures on many length scales. Self-assembly of nano-scale devices has given fresh impetus to understanding how solidification produces ordered, and sometimes complex, structures from disordered precursors. Abstract | References Full text: Acrobat PDF
897		The structure of the world from pure numbers F J Tipler 68 No 4 (April 2004) This review investigates the relationship between physics and mathematics. It argues that requiring the joint mathematical consistency of the Standard Model of particle physics and the DeWitt-Feynman-Weinberg theory of quantum gravity can resolve the horizon, flatness, and isotropy problems of cosmology. It provides a natural explanation for dark matter and dark energy. It proposes several simple experiments to test the hypothesis. Abstract | References Full text: Acrobat PDF
1129		Single-photon sources Brahim Lounis 68 No 5 (May 2005) New concepts for single-photon sources, or “photon guns”, originate from recent progress in the optical detection, characterization, and manipulation of single quantum objects. This article reviews basic concepts in quantum optics, and discusses potential applications of single-photon states to optical processing of quantum information: cryptography, computing, and communication. We expect single photons to soon go from demonstrations to applications, and to bring with them the first practical uses of quantum information. Abstract | References Full text: Acrobat PDF
1251		Reflection anisotropy spectroscopy P Weightman, D S Martin, T Farrell and R J Cole 68 No 6 (June 2005) Reflection anisotropy spectroscopy (RAS) is a non-destructive optical probe of surfaces that is capable of operation within a wide range of environments, where it has a clear advantage over UHV-based probes for investigating surface phenomena. This article reviews the principles, instrumentation and theoretical considerations of RAS, recent progress in its application to investigate surface phenomena and applications in fields including electrochemistry, molecular assembly, liquid crystal device fabrication and remote stress sensing. Abstract | References Full text: Acrobat PDF
1343		Global warming John Houghton 68 No 6 (June 2005) Global warming is widely recognized as the most important environmental issue of our day. This review describes the basic science of global warming, its likely impacts both on human communities and on natural ecosystems and the actions that can be taken to mitigate or to adapt to it. Abstract | References Full text: Acrobat PDF
1883		Near fields in nanostructures Christian Girard 68 No 8 (August 2005) Near–field optical microscopes are now used to precisely image the electromagnetic field distributions inside nanostructures. This article reviews the physics of this so-called nano–optics, presenting the main theoretical techniques and typical calculations. It details procedures for optimization of the energy transfer efficiency inside addressed nanostructures for solving the problem of optical addressing of both passive and active nanostructures in a subwavelength area. Finally it revisits the concept of photonic local density of states in near–field optics Abstract | References Full text: Acrobat PDF
2701		Physical limits of silicon transistors and circuits Robert W Keyes 68 No 12 (December 2005) The rapid advancement of transistor electronics has relied on miniaturization and the search for limits is an important question. This article aims to convey the essential physics of the topic for scientists not closely aligned with the development of the technology. It reviews the history and development of transistor technology and describes the physics of semiconductor devices and transistors then discusses the changes in transistor characteristics as sizes are reduced. Abstract | References Full text: Acrobat PDF
2829		The mathematics and physics of knots Louis H Kauffman 68 No 12 (December 2005) This article gives an introduction to relationships between knot theory and theoretical physics. It gives an exposition of the theory of polynomial invariants of knots and links, the Witten functional integral formulation of knot and link invariants, and the beginnings of topological quantum field theory, and shows how the theory of knots is related to a number of key issues in mathematical physics, including loop quantum gravity and quantum information theory. Abstract | References Full text: Acrobat PDF