The connection between mathematics and physics .•. Is it only that physicists talk in the language of mathematics? It is more. This book describes how mathematics associates to some important physical abstractions (modelsl its own mental constructions, which are far removed from the direct impressions of experience and physical experiment.

The Indian National Science Academy was established in January 1935 with the objective of promoting science in India and harnessing scientific knowledge for the cause of humanity and national welfare. In 1968 it was designated as the adhering organisation in India to the International Council for Scientific Union (ICSU) on behalf of the Government of India. Over the years, the Academy has published a number of journals, volumes, biographical memoirs, etc. The year 2009–2010 will be specially celebrated to mark the Platinum Jubilee of the Academy. Many programmes are planned in different centres in India on this occasion. In addition, the Academy has decided to publish a number of special volumes on different s- jects ranging from earth sciences to life sciences. This volume is on Physics and Chemistry of the Earth’s Interior. One of the main objectives of geophysicists is to establish the internal structure of the earth as revealed by seismic tomography. It is also their primary goal to correlate geophy- cal data to reveal thermal and chemical state of the crust, mantle and core of the earth. In - der to interpret seismic velocities and associated density and elastic properties in terms of mineralogical and petrological models of the earth’s interior, thermodynamic and hi- pressure temperature data from mineral physics are essential. With the advent of different types of multi-anvil and laser-heated diamond anvil equipment, it is now possible to simulate conditions prevalent even in the lower mantle and core of the earth.

As physicists, mathematicians or engineers, we are all involved with mathematical calculations in our everyday work. Most of the laborious, complicated, and time-consuming calculations have to be done over and over again if we want to check the validity of our assumptions and derive new phenomena from changing models. Even in the age of computers, we often use paper and pencil to do our calculations. However, computer programs like Mathematica have revolutionized our working methods. Mathematica not only supports popular numerical calculations but also enables us to do exact analytical calculations by computer. Once we know the analytical representations of physical phenomena, we are able to use Mathematica to create graphical representations of these relations. Days of calculations by hand have shrunk to minutes by using Mathematica. Results can be verified within a few seconds, a task that took hours if not days in the past. The present text uses Mathematica as a tool to discuss andto solve examples from physics. The intention of this book is to demonstrate the usefulness of Mathematica in everyday applications. We will not give a complete description of its syntax but demonstrate by examples the use of its language. In particular, we show how this modern tool is used to solve classical problems. viii Preface This second edition of Mathematica in Theoretical Physics seeks to prevent the objectives and emphasis of the previous edition.

The book describes the branch of astrophysics in which processes in the universe are investigated with experimental methods known from particle physics experiments. After a historical introduction to the basics of elementary particles, their interactions and the relevant detection techniques are described. The main body of the book concerns cosmic rays. The modern aspects of astroparticle physics are described in a chapter on cosmology. The book provides an orientation in the field of astroparticle physics that many beginners might look for. The physics issues are presented with little mathematics, and the results are illustrated by many diagrams. The reader has a chance to enter this field of astrophysics with a book that closes the gap between expert and popular level.

During July 1991. a group of 99 physicists from 57 laboratories in 27 countries met in Erice for the 29th Course of the International School of Subnuclear Physics. The countries represented were: Algeria. Argentina. Austria. Brazil. Canada. China. France. Germany. Greece. India. Ireland. Israel. Italy. New Zealand. Norway. Pakistan. Poland. Portugal. Rumania. Spain. Sweden. Switzerland. Thailand. Turkey. The Union of Soviet Socialist Republics. the United Kingdom. and the United States of America. The School was sponsored by the European Physical Society (EPS). the Italian Ministry of Education (MPI). the Italian Ministry of University and Scientific Research. the Sicilian Regional Government (ERS). and the Weizmann Institute of Science. The opening lecture of the School was given by Professor Lev Okun. A few remarks are in order. In the pre-Gorbachev era. Professor Okun's case was the most difficult: in spite of many invitations he was not allowed to come and lecture at Erice. Nowadays the hard times have nearly been forgotten. It is with pleasure that I recall here a discussion I had with my friend Lev Okun in my house during one of his rare visits to CERN. The after-dinner topic was Galileo Galilei and his great discovery; i. e . • the equality between gravitational and inertial masses - a discovery that we are celebrating now. four hundred years later. Here is a synthesis of Professor Okun's position: given a massive particle. the only quantity we should consider when talking about masses.

In this book, the fundamentals of magnetism are treated, starting at an introductory level. The origin of magnetic moments, the response to an applied magnetic field, and the various interactions giving rise to different types of magnetic ordering in solids are presented and many examples are given. Crystalline-electric-field effects are treated at a level that is sufficient to provide the basic knowledge necessary in understanding the properties of materials in which these effects play a role. Itinerant-electron magnetism is presented on a similar basis. Particular attention has been given to magnetocrystalline magnetic anisotropy and the magnetocaloric effect. Also, the usual techniques for magnetic measurements are presented. About half of the book is devoted to magnetic materials and the properties that make them suitable for numerous applications. The state of the art is presented of permanent magnets, high-density recording materials, soft-magnetic materials, Invar alloys and magnetostrictive materials. Many references are given.