Journal•ISSN: 0143-0807

# European Journal of Physics

IOP Publishing

About: European Journal of Physics is an academic journal published by IOP Publishing. The journal publishes majorly in the area(s): Physics & Magnetic field. It has an ISSN identifier of 0143-0807. Over the lifetime, 5090 publications have been published receiving 49557 citations.

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TL;DR: Anyone involved in scientific computing ought to have a copy of at least one version of Numerical Recipes, and there also ought to be copies in every library.

Abstract: The two Numerical Recipes books are marvellous. The principal book, The Art of Scientific Computing, contains program listings for almost every conceivable requirement, and it also contains a well written discussion of the algorithms and the numerical methods involved. The Example Book provides a complete driving program, with helpful notes, for nearly all the routines in the principal book. The first edition of Numerical Recipes: The Art of Scientific Computing was published in 1986 in two versions, one with programs in Fortran, the other with programs in Pascal. There were subsequent versions with programs in BASIC and in C. The second, enlarged edition was published in 1992, again in two versions, one with programs in Fortran (NR(F)), the other with programs in C (NR(C)). In 1996 the authors produced Numerical Recipes in Fortran 90: The Art of Parallel Scientific Computing as a supplement, called Volume 2, with the original (Fortran) version referred to as Volume 1. Numerical Recipes in C++ (NR(C++)) is another version of the 1992 edition. The numerical recipes are also available on a CD ROM: if you want to use any of the recipes, I would strongly advise you to buy the CD ROM. The CD ROM contains the programs in all the languages. When the first edition was published I bought it, and have also bought copies of the other editions as they have appeared. Anyone involved in scientific computing ought to have a copy of at least one version of Numerical Recipes, and there also ought to be copies in every library. If you already have NR(F), should you buy the NR(C++) and, if not, which version should you buy? In the preface to Volume 2 of NR(F), the authors say 'C and C++ programmers have not been far from our minds as we have written this volume, and we think that you will find that time spent in absorbing its principal lessons will be amply repaid in the future as C and C++ eventually develop standard parallel extensions'. In the preface and introduction to NR(C++), the authors point out some of the problems in the use of C++ in scientific computing. I have not found any mention of parallel computing in NR(C++). Fortran has quite a lot going for it. As someone who has used it in most of its versions from Fortran II, I have seen it develop and leave behind other languages promoted by various enthusiasts: who now uses Algol or Pascal? I think it unlikely that C++ will disappear: it was devised as a systems language, and can also be used for other purposes such as scientific computing. It is possible that Fortran will disappear, but Fortran has the strengths that it can develop, that there are extensive Fortran subroutine libraries, and that it has been developed for parallel computing. To argue with programmers as to which is the best language to use is sterile. If you wish to use C++, then buy NR(C++), but you should also look at volume 2 of NR(F). If you are a Fortran programmer, then make sure you have NR(F), volumes 1 and 2. But whichever language you use, make sure you have one version or the other, and the CD ROM. The Example Book provides listings of complete programs to run nearly all the routines in NR, frequently based on cases where an anlytical solution is available. It is helpful when developing a new program incorporating an unfamiliar routine to see that routine actually working, and this is what the programs in the Example Book achieve. I started teaching computational physics before Numerical Recipes was published. If I were starting again, I would make heavy use of both The Art of Scientific Computing and of the Example Book. Every computational physics teaching laboratory should have both volumes: the programs in the Example Book are included on the CD ROM, but the extra commentary in the book itself is of considerable value. P Borcherds

1,367 citations

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TL;DR: In this article, the basic physical effects leading to radiation-induced forces are reviewed and a simple derivation of the mathematical expressions for the classical light forces is given, and the influence of quantum fluctuations is demonstrated and the possibilities for trapping neutral particles are discussed.

Abstract: The basic physical effects leading to radiation-induced forces are reviewed. A simple derivation of the mathematical expressions for the classical light forces is given. The influence of quantum fluctuations is demonstrated and the possibilities for trapping neutral particles are discussed. Two recent successful laser cooling and trapping experiments are described to illustrate the applications of the basic principles.

1,238 citations

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TL;DR: In this paper, the properties of a single memristor, memristors in series and parallel, as well as ideal MC, MCL and MCL circuits are discussed.

Abstract: We present an introduction to and a tutorial on the properties of the recently discovered ideal circuit element, a memristor. By definition, a memristor M relates the charge q and the magnetic flux in a circuit and complements a resistor R, a capacitor C and an inductor L as an ingredient of ideal electrical circuits. The properties of these three elements and their circuits are a part of the standard curricula. The existence of the memristor as the fourth ideal circuit element was predicted in 1971 based on symmetry arguments, but was clearly experimentally demonstrated just last year. We present the properties of a single memristor, memristors in series and parallel, as well as ideal memristor–capacitor (MC), memristor–inductor (ML) and memristor–capacitor–inductor (MCL) circuits. We find that the memristor has hysteretic current–voltage characteristics. We show that the ideal MC (ML) circuit undergoes non-exponential charge (current) decay with two time scales and that by switching the polarity of the capacitor, an ideal MCL circuit can be tuned from overdamped to underdamped. We present simple models which show that these unusual properties are closely related to the memristor's internal dynamics. This tutorial complements the pedagogy of ideal circuit elements (R, C and L) and the properties of their circuits, and is aimed at undergraduate physics and electrical engineering students.

719 citations

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TL;DR: The history of matter from the Big Bang to the present can be found in this paper, where the authors describe the synthesis and evolution of atomic nuclei by thermonuclear reactions.

Abstract: ISBN: 0 691 01147 8 The subtitle of the book is An investigation of the history of matter, from the Big Bang to the present. The author tells us in the preface what sort of book the present text is intended to be. `This book is not intended to be a scientific history, a textbook or a review, although it has some of these elements and could serve these purposes. It is intended to be what was well described by Professor S Chandrasekhar in reference to his own goals for scientific books: ``...a certain viewpoint of the field, written by one who has been an active participant in its development...''. The subject is the synthesis and evolution of atomic nuclei, by thermonuclear reactions, from the Big Bang to the present. What is the origin and history of the matter of which we are made?' This 600-page-long book contains 14 chapters with thorough expositions of topics such as Observed abundances of nuclei, Aspects of nuclear physics, Cosmological nucleosynthesis, Properties of different types of stars, Thermonuclear explosions, Gravitational collapse, Supernovae and Galactic evolution. Each topic is treated in a fundamental way, exhibiting the physical ideas, and the way they are formulated mathematically, in order that models with quantitative predictive power may be constructed. The book also contains several appendixes with additional mathematical treatments of Equations of state, Stellar structure and Supernovae light curves. Also there are 712 references, 119 figures and 68 tables, and it is useful that the author has provided lists of the figures and tables at the beginning of the book. Concerning the way he writes about the evolution of stars, Arnett says: `Because of the complicated interplay of the various physical processes involved, stellar evolutionary theory involves the construction of complex mathematical models. Because of this complexity, the equations which result are almost never soluble in a simple way. To proceed it was necessary to resort to brute force, and build numerical models of stars in a computer. In this book, complex numerical results are often described in terms of analytic approximations: simpler equations are solved by conventional means, and then woven together to represent the actual solution. There is a fundamental reason for this approach. Stellar evolutionary calculations may profitably be viewed as numerical experiments. Representation of these reams of numbers by simple approximations is a step toward understanding the interplay of the various physical processes involved.' Much of my own research has been concerned with cosmological problems, so I read the chapter on Cosmological nucleosynthesis with particular attention. A close reading reveals some properties of the presentation that seem characteristic of the book. Initially there are some physical considerations, in the present case about cosmic kinetics. A simple model is chosen and described mathematically; here a `Newtonian' dust-filled spherical mass distribution. Arnett's book is mainly concerned with nucleosynthesis and not with relativistic cosmology, so the conceptual framework of the latter is not presented. For example, the expansion factor is treated as the radius of the cosmic mass distribution, and the cosmic red shift of light is presented on few lines in a rather ad hoc manner. The effect of pressure on the dynamics of the cosmic fluid is introduced by writing a relativistic formula with reference to Tolman's classical book on cosmology. Arnett's book is not logically self-contained. You should not expect to be able to read this book from page 1 and onwards understanding all that you read from the text. The topic of the book is just too encompassing to allow this. The reader wanting to understand everything in Arnett's book must study several of the references and be prepared to take some years! The bonus would be that this person would end up as a good physicist. The book is obviously intended to become a standard reference volume on Supernovae and Nucleosynthesis, and it clearly will succeed in this. This is a book all researchers, from graduate students to well established senior researchers on these topics should consult. If you intend to work for some time on these matters you should have your own copy of the book!

557 citations

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TL;DR: In this article, it was shown that stable zones always exist on the axis of a field with rotational symmetry, and include the inflection point of the magnitude of the field.

Abstract: Diamagnetic objects are repelled by magnetic fields. If the fields are strong enough, this repulsion can balance gravity, and objects levitated in this way can be held in stable equilibrium, apparently violating Earnshaw's theorem. In fact Earnshaw's theorem does not apply to induced magnetism, and it is possible for the total energy (gravitational+magnetic) to possess a minimum. General stability conditions are derived, and it is shown that stable zones always exist on the axis of a field with rotational symmetry, and include the inflection point of the magnitude of the field. For the field inside a solenoid, the zone is calculated in detail; if the solenoid is long, the zone is centred on the top end, and its vertical extent is about half the radius of the solenoid. The theory explains recent experiments by Geimet al, in which a variety of objects (one of which was a living frog) was levitated in a field of about 16 T. Similar ideas explain the stability of a spinning magnet (Levitron TM ) above a magnetized base plate. Stable levitation

435 citations