Physica Scripta is published by the IOP on behalf of the Royal Swedish Academy of Sciences for the Science Academies and the Physical Societies of the Nordic Countries.
Crystallography and the Gregori Aminoff Prize
To mark the fact that 2014 has been designated the 'International Year of Crystallography', Physica Scripta will be publishing a virtual issue containing Invited Comments on the history of crystallography, as well as autobiographical articles from some of the current and previous winners of the Gregori Aminoff Prize. You can read the first papers published in this virtual issue here.
21st Central European Workshop on Quantum Optics - Poster Prize
Physica Scripta is pleased to announce that the 21st Central European Workshop on Quantum Optics Poster Prize was awarded to Dr Sahand Mahmoodian of the Niels Bohr Institute, University of Copenhagen for the work 'Efficiently interfacing photons with quantum dots in photonic crystal waveguides'.
Proceedings of the International Conference on Research and Applications of Plasmas, held in Poland in September 2013, are now online as a Topical Issue of Physica Scripta. These papers will be free to read until the end of June 2014.
Our Topical Issue based on the 14th International Conference on Plasma-Facing Materials and Components for Fusion Applications has now been published online.
Selected papers from FN&MT-2013
Selected papers from the International Conference on Functional Materials and Nanotechnologies, held in April 2013 in Estonia, have been published in a special section of Physica Scripta.
Highlights of 2013
Physica Scripta proudly presents the Highlights of 2013 collection. These articles published in 2013 cover a broad spectrum of physics research selected based on the number of citations, the number of downloads, or their scientific impact.
In the last 30 days
J E Hirsch 2013 Phys. Scr. 88 035704
Conventional Hubbard models do not take into account the fact that the wavefunction of an electron in an atomic orbital expands when a second electron occupies the orbital. Dynamic Hubbard models have been proposed to describe this physics. These models reflect the fact that electronic materials are generically not electron–hole symmetric, and they give rise to superconductivity driven by lowering of kinetic energy when the electronic energy band is almost full, with higher transition temperatures resulting when the ions are negatively charged. We show that the charge distribution in dynamic Hubbard models can be highly inhomogeneous in the presence of disorder, and that a finite system will expel negative charge from the interior to the surface, and that these tendencies are largest in the parameter regime where the models give rise to highest superconducting transition temperatures. High T c cuprate materials exhibit charge inhomogeneity and they exhibit tunneling asymmetry, a larger tendency to emit electrons rather than holes in normal–insulating–superconducting tunnel junctions. We propose that these properties, as well as their high T c, are evidence that they are governed by the physics described by dynamic Hubbard models. Below the superconducting transition temperature the models considered here describe a negatively charged superfluid and positively charged quasiparticles, unlike the situation in conventional Bardeen–Cooper–Schrieffer superconductors where quasiparticles are charge neutral on average. We examine the temperature dependence of the superfluid and quasiparticle charges and conclude that spontaneous electric fields should be observable in the interior and in the vicinity of superconducting materials described by these models at sufficiently low temperatures. We furthermore suggest that the dynamics of the negatively charged superfluid and positively charged quasiparticles in dynamic Hubbard models can provide an explanation for the Meissner effect observed in high T c and low T c superconducting materials.
Garry Robinson and Ian Robinson 2013 Phys. Scr. 88 018101
In this paper the differential equations which govern the motion of a spherical projectile rotating about an arbitrary axis in the presence of an arbitrary ‘wind’ are developed. Three forces are assumed to act on the projectile: (i) gravity, (ii) a drag force proportional to the square of the projectile's velocity and in the opposite direction to this velocity and (iii) a lift or ‘Magnus’ force also assumed to be proportional to the square of the projectile's velocity and in a direction perpendicular to both this velocity and the angular velocity vector of the projectile. The problem has been coded in Matlab and some illustrative model trajectories are presented for ‘ball-games’, specifically golf and cricket, although the equations could equally well be applied to other ball-games such as tennis, soccer or baseball.
Spin about an arbitrary axis allows for the treatment of situations where, for example, the spin has a component about the direction of travel. In the case of a cricket ball the subtle behaviour of so-called ‘drift’, particularly ‘late drift’, and also ‘dip’, which may be produced by a slow bowler's off or leg-spin, are investigated. It is found that the trajectories obtained are broadly in accord with those observed in practice. We envisage that this paper may be useful in two ways: (i) for its inherent scientific value as, to the best of our knowledge, the fundamental equations derived here have not appeared in the literature and (ii) in cultivating student interest in the numerical solution of differential equations, since so many of them actively participate in ball-games, and they will be able to compare their own practical experience with the overall trends indicated by the numerical results.
As the paper presents equations which can be further extended, it may be of interest to research workers. However, since only the most basic principles of fundamental mechanics are employed, it should be well within the grasp of first year university students in physics and engineering and, with the guidance of teachers, good final year secondary school students. The trajectory results included may be useful to sporting personnel with no formal training in physics.
Sukang Bae et al 2012 Phys. Scr. 2012 014024
Since the first isolation of graphene in 2004 by mechanical exfoliation from graphite, many people have tried to synthesize large-scale graphene using various chemical methods. In particular, there has been a great number of advances in the synthesis of graphene using chemical vapor deposition (CVD) on metal substrates such as Ni and Cu. Recently, a method to synthesize ultra-large-scale (~30 inch) graphene films using roll-to-roll transfer and chemical doping processes was developed that shows excellent electrical and physical properties suitable for practical applications on a large scale. Considering the outstanding scalability/processibility of roll-to-roll and CVD methods as well as the extraordinary flexibility/conductivity of graphene films, we expect that transparent graphene electrodes can replace indium tin oxide in the near future.
K S Novoselov and A H Castro Neto 2012 Phys. Scr. 2012 014006
Graphene is just one example of a large class of two-dimensional crystals. These crystals can either be extracted from layered three-dimensional materials or grown artificially by several different methods. Furthermore, they present physical properties that are unique because of the low dimensionality and their special crystal structure. They have potential for semiconducting behavior, magnetism, superconductivity, and even more complex many-body phenomena. Two-dimensional crystals can also be assembled in three-dimensional heterostructures that do not exist in nature and have tailored properties, opening an entirely new chapter in condensed matter research.
Yigong Shi 2014 Phys. Scr. 89 068004
As a Chinese born and raised in central China, I came to the United States for graduate education in 1990. Eighteen years later, I resigned my tenured faculty position at Princeton University and returned to my alma mater Tsinghua University. In this review, I share my experiences and reflections as a graduate student, a postdoctoral fellow, and an independent scientist in both Princeton and Beijing. Much focus is given to my research effort in the field of programmed cell death (also known as apoptosis). Systematic structural biology, which combines x-ray crystallography with other biochemical and biophysical methods, has led to comprehensive understanding of the underlying molecular mechanisms that govern the initiation, execution, and regulation of apoptosis.
H Rezvani Nikabadi et al 2013 Phys. Scr. 87 025802
In this paper, a facile method for the synthesis of gold nanoseeds on the functionalized surface of silica nanoparticles has been investigated. Mono-dispersed silica particles and gold nanoparticles were prepared by the chemical reduction method. The thickness of the Au shell was well controlled by repeating the reduction time of HAuCl 4 on silica/3-aminopropyltriethoxysilane (APTES)/initial gold nanoparticles. The prepared SiO 2@gold core/shell nanoparticles were studied using x-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and ultraviolet visible (UV–Vis) spectroscopy. The TEM images indicated that the silica nanoparticles were spherical in shape with 100 nm diameters and functionalizing silica nanoparticles with a layer of bi-functional APTES molecules and tetrakis hydroxy methyl phosphonium chloride. The gold nanoparticles show a narrow size of up to 5 nm and by growing gold nanoseeds over the silica cores a red shift in the maximum absorbance of UV–Vis spectroscopy from 524 to 637 nm was observed.
D J Dunstan and D J Hodgson 2014 Phys. Scr. 89 068002
Many gardeners and horticulturalists seek non-chemical methods to control populations of snails. It has frequently been reported that snails that are marked and removed from a garden are later found in the garden again. This phenomenon is often cited as evidence for a homing instinct. We report a systematic study of the snail population in a small suburban garden, in which large numbers of snails were marked and removed over a period of about 6 months. While many returned, inferring a homing instinct from this evidence requires statistical modelling. Monte Carlo techniques demonstrate that movements of snails are better explained by drift under the influence of a homing instinct than by random diffusion. Maximum likelihood techniques infer the existence of two groups of snails in the garden: members of a larger population that show little affinity to the garden itself, and core members of a local garden population that regularly return to their home if removed. The data are strongly suggestive of a homing instinct, but also reveal that snail-throwing can work as a pest management strategy.
Klaus Blaum et al 2013 Phys. Scr. 2013 014017
Atomic physics techniques for the determination of ground-state properties of radioactive isotopes are very sensitive and provide accurate masses, binding energies, Q-values, charge radii, spins and electromagnetic moments. Many fields in nuclear physics benefit from these highly accurate numbers. They give insight into details of the nuclear structure for a better understanding of the underlying effective interactions, provide important input for studies of fundamental symmetries in physics, and help to understand the nucleosynthesis processes that are responsible for the observed chemical abundances in the Universe. Penning-trap and storage-ring mass spectrometry as well as laser spectroscopy of radioactive nuclei have now been used for a long time but significant progress has been achieved in these fields within the last decade. The basic principles of laser spectroscopic investigations, Penning-trap and storage-ring mass measurements of short-lived nuclei are summarized and selected physics results are discussed.
A Wolszczan 2008 Phys. Scr. 2008 014005
Developments in the investigations of the known planets around two millisecond radio pulsars, PSR B1257+12 and PSR B1620−26, and in the searches for dusty disks around pulsars are discussed and related to relevant issues in astronomy of the planets around normal stars. The unambiguous determination of true masses and orbital inclinations of two of the three planets in the PSR B1257+12 system has been achieved by means of modeling their mean motion resonance condition. An approximate coplanarity of the orbits of these terrestrial-mass planets points to a disk origin of the system. A tentative Spitzer discovery of a cool, ~10 M ⊕ dusty disk around the x-ray pulsar, 4U 0142+61, further suggests that disks which may form planets can survive in a neutron star environment. Currently available upper limits on infrared emission from dust around other pulsars do not exclude a possible existence of circumpulsar disks with masses reaching up to a few hundred M ⊕. The direct detection of a white dwarf companion to PSR B1620−26 has resulted in tighter constraints on the nature of a giant planet orbiting this binary system. The existence of such a planet around this neutron star, in a metal-poor environment of the globular cluster M4, raises questions concerning the established relationship between stellar metallicity and the occurence of planets around normal stars.
Y Blumenfeld et al 2013 Phys. Scr. 2013 014023
Radioactive ion beam facilities are transforming nuclear science by making beams of exotic nuclei with various properties available for experiments. New infrastructures and development of existing installations enlarges the scientific scope continuously. An overview of the main production, separation and beam handling methods with focus on recent developments is done, as well as a survey of existing and forthcoming facilities world-wide.