Hanns Ruder – författare

In this book we summarize the essential results of our efforts over the years to calculate energies, wave functions, and electromagnetic transitions of atoms as functions of the magnetic field strength from laboratory fields up to neutron star magnetic fields. Motivated by the observational evidence of huge magnetic 5 fields with strengths up to 10 T in the vicinity of white dwarf stars and of up 9 to 10 T in the vicinity of neutron stars the authors, together with coworkers and candidates for doctor and diploma degrees, have investigated this ,fasci­ nating quantum mechanical problem more or less continuously since 1978. The extensive tables and figures in the appendices represent the most complete data set to date in this field of research. For practical use all numbers are available by "anonymous ftp" over Internet. The first direct measurement of a neutron star magnetic field by Trum­ per and his group, who observed a cyclotron feature at about 50 ke V in the spectrum of the X-ray pulsar Hercules X-I corresponding to a field strength of 8 several 10 T, stimulated investigations of atoms within the framework of the adiabatic approximation, which is well justified for such field strengths. This method and its results are discussed in Chaps. 3, 5, and 6.

In this book we summarize the essential results of our efforts over the years to calculate energies, wave functions, and electromagnetic transitions of atoms as functions of the magnetic field strength from laboratory fields up to neutron star magnetic fields. Motivated by the observational evidence of huge magnetic 5 fields with strengths up to 10 T in the vicinity of white dwarf stars and of up 9 to 10 T in the vicinity of neutron stars the authors, together with coworkers and candidates for doctor and diploma degrees, have investigated this ,fasci­ nating quantum mechanical problem more or less continuously since 1978. The extensive tables and figures in the appendices represent the most complete data set to date in this field of research. For practical use all numbers are available by "anonymous ftp" over Internet. The first direct measurement of a neutron star magnetic field by Trum­ per and his group, who observed a cyclotron feature at about 50 ke V in the spectrum of the X-ray pulsar Hercules X-I corresponding to a field strength of 8 several 10 T, stimulated investigations of atoms within the framework of the adiabatic approximation, which is well justified for such field strengths. This method and its results are discussed in Chaps. 3, 5, and 6.

For this set of lectures we assumed that the reader has a reasonable back­ ground in physics and some knowledge of general relativity, the modern theory of gravity in macrophysics, and cosmology. Computer methods are present­ ed by leading experts in the three main domains: in numerics, in computer algebra, and in visualization. The idea was that each of these subdisciplines is introduced by an extended set of main lectures and that each is conceived as being of comparable ''importance. Therefpre we believe that the book represents a good introduction into scientific I computing for any student who wants to specialize in relativity, gravitation, and/or astrophysics. We took great care to select lecturers who teach in a comprehensible way and who are, at the same time, at the research front of their respective field. In numerics we had the privilege of having a lecturer from the National Center for Supercomputing Applications (NCSA, Champaign, IL, USA) and some from other leading institutions of the world; visualization was taught by a visualization expert from Boeing; and in com­ puter algebra we took recourse to practitioners of different computer algebra systems as applied to classical general relativity up to quantum gravity and differential geometry.

For this set of lectures we assumed that the reader has a reasonable back­ ground in physics and some knowledge of general relativity, the modern theory of gravity in macrophysics, and cosmology. Computer methods are present­ ed by leading experts in the three main domains: in numerics, in computer algebra, and in visualization. The idea was that each of these subdisciplines is introduced by an extended set of main lectures and that each is conceived as being of comparable 'importance. Therefpre we believe that the book represents a good introduction into scientific I computing for any student who wants to specialize in relativity, gravitation, and/or astrophysics. We took great care to select lecturers who teach in a comprehensible way and who are, at the same time, at the research front of their respective field. In numerics we had the privilege of having a lecturer from the National Center for Supercomputing Applications (NCSA, Champaign, IL, USA) and some from other leading institutions of the world; visualization was taught by a visualization expert from Boeing; and in com­ puter algebra we took recourse to practitioners of different computer algebra systems as applied to classical general relativity up to quantum gravity and differential geometry.

This volume is published in honor of Friedrich Hund's 100th birthday. It is a modern review on matter at high densities and pressures in astrophysics from Hund's early contribution to present-day ideas. The relation between the equation of state and the structure of compact cosmic objects is discussed, and two main contributions deal with the equation of state of baryonic matter at nuclear densities and with the numerical solution of the general relativistic field equations for non-rotating and rapidly rotating neutron stars. In a final chapter the present state of asteroseismology is presented as a tool to explore the interior of cosmic objects by analyzing the observed free oscillations of the Earth, the Sun, and white dwarf stars.

This book summarizes the lectures given at the 162. WE-Heraeus Seminar which took place in the house of the German Physical Society in Bad Honnefin August 1996. Already the number 162 shows the activity and effectiveness of the WE-Heraeus Foundation. We would like to express our thanks to Jutta Adam and Dr. Volker Schafer for the almost incredibly simple and unbureaucratical procedure of funding, organization and realization, and, of course, to the founders. Similar to the 152. WE-Heraeus Seminar Relativity and Scientific Computing (Springer Verlag 1996), this seminar was a joint venture of the Astronomical Society (AG) and of the Section ''Gravitation und Relativity Theory'' of the German Physical Society (DPG). Since Einstein has developed his Theory of General Relativity more than 80 years ago, the situation has changed dramatically. In the first decades main efforts were untertaken for a better understanding and for the experimental verification of the theory. Mean­ while General Relativity (GR) is one of the experimentally best confirmed theories with 13 an accuracy better than 10- ! Consequently, GR has become a powerful tool for the investigation of cosmic processes where strong gravitational fields are involved. The state of the art of our knowledge is summarized by Jiirgen Ehlers in the first chapter. An impressive example of the change of the situation is the gravitational light deflection.

This book summarizes the lectures given at the 162. WE-Heraeus Seminar which took place in the house of the German Physical Society in Bad Honnefin August 1996. Already the number 162 shows the activity and effectiveness of the WE-Heraeus Foundation. We would like to express our thanks to Jutta Adam and Dr. Volker Schafer for the almost incredibly simple and unbureaucratical procedure of funding, organization and realization, and, of course, to the founders. Similar to the 152. WE-Heraeus Seminar Relativity and Scientific Computing (Springer Verlag 1996), this seminar was a joint venture of the Astronomical Society (AG) and of the Section 'Gravitation und Relativity Theory' of the German Physical Society (DPG). Since Einstein has developed his Theory of General Relativity more than 80 years ago, the situation has changed dramatically. In the first decades main efforts were untertaken for a better understanding and for the experimental verification of the theory. Mean­ while General Relativity (GR) is one of the experimentally best confirmed theories with 13 an accuracy better than 10- ! Consequently, GR has become a powerful tool for the investigation of cosmic processes where strong gravitational fields are involved. The state of the art of our knowledge is summarized by Jiirgen Ehlers in the first chapter. An impressive example of the change of the situation is the gravitational light deflection.