H. Haken – författare

This collection of papers presented at the Enrico Fermi School considers the subject of synergetics as a firmly established field of interdisciplinary research, ranging from physics, chemistry and biology, to subjects like economy and sociology. These proceedings focus on the natural sciences.

Die Festkörperphysik ist eines der großen Hauptgebiete der heutigen Physik. Der Festkörper stellt mit seinen verwickelten elektrischen, optischen, thermischen und magnetischen Eigenschaften ein äußerst reizvolles Objekt moderner Grundlagen­ forschung dar. In der Tat gelingt es hier, die oft sehr komplizierten Erscheinungen aufzuklären und bis in die Details hinein zu verfolgen. Das damit verbundene tief­ greifende Verständnis der physikalischen Vorgänge im Festkörper führt darüber­ hinaus zu äußerst wichtigen Anwendungen, z. B. in der Nachrichten-und Computer­ technik. Der Studierende, der sich in dieses Gebiet einarbeiten will, stellt allerdings sehr rasch fest, daß hier in großem Umfang Begriffsbildungen und Methoden der Quantenfeld­ theorie verwendet werden. Diese Methoden gestatten es nicht nur, die physikalischen Vorgänge im Festkörper in eleganter Weise zu beschreiben, sondern sie haben auch zu grundsätzlich neuen Erkenntnissen geführt. Als hervorragendes Beispiel sei hier nur die Erklärung der Supraleitung erwähnt. Andererseits wird dem Studierenden in einer Kursvorlesung, etwa der Quanten­ mechanik, kaum die Möglichkeit geboten, dieses wichtige Gebiet kennenzulernen. Aufgabe dieses Buches soll es sein, diese Lücke zu schließen, indem es den Leser in einfacher Weise an die Begriffsbildungen und Methoden der Quantenfeldtheorie her­ anführt. So sollte ein Leser, der mit den mathematischen Kenntnissen der ersten drei Semes·ter und den Grundbegriffen der Quantenmechanik vertraut ist, ohne weiteres in der Lage sein, sich mit Hilfe dieses Buches in die Quantenfeldtheorie des Fest­ körpers einzuarbeiten.

Die Festkörperphysik ist eines der großen Hauptgebiete der heutigen Physik. Der Festkörper stellt mit seinen verwickelten elektrischen, optischen, thermischen und magnetischen Eigenschaften ein äußerst reizvolles Objekt moderner Grundlagen­ forschung dar. In der Tat gelingt es hier, die oft sehr komplizierten Erscheinungen aufzuklären und bis in die Details hinein zu verfolgen. Das damit verbundene tief­ greifende Verständnis der physikalischen Vorgänge im Festkörper führt darüber­ hinaus zu äußerst wichtigen Anwendungen, z. B. in der Nachrichten-und Computer­ technik. Der Studierende, der sich in dieses Gebiet einarbeiten will, stellt allerdings sehr rasch fest, daß hier in großem Umfang Begriffsbildungen und Methoden der Quantenfeld­ theorie verwendet werden. Diese Methoden gestatten es nicht nur, die physikalischen Vorgänge im Festkörper in eleganter Weise zu beschreiben, sondern sie haben auch zu grundsätzlich neuen Erkenntnissen geführt. Als hervorragendes Beispiel sei hier nur die Erklärung der Supraleitung erwähnt. Andererseits wird dem Studierenden in einer Kursvorlesung, etwa der Quanten­ mechanik, kaum die Möglichkeit geboten, dieses wichtige Gebiet kennenzulernen. Aufgabe dieses Buches soll es sein, diese Lücke zu schließen, indem es den Leser in einfacher Weise an die Begriffsbildungen und Methoden der Quantenfeldtheorie her­ anführt. So sollte ein Leser, der mit den mathematischen Kenntnissen der ersten drei Semes·ter und den Grundbegriffen der Quantenmechanik vertraut ist, ohne weiteres in der Lage sein, sich mit Hilfe dieses Buches in die Quantenfeldtheorie des Fest­ körpers einzuarbeiten.

This book contains the invited papers of an international symposium on Synergetics which was held at ZIF (Center for interdisciplinary research) at Bielefeld. Fed. Rep. of Germany. Sept. 24. -29 . • 1979. In keeping with our previous meetings. this one was truly interdisciplinary. Synergetic systems are those that can produce macroscopic spatial. temporal or functional structures in a self-organized way. I think that these proceedings draw a rather coherent picture of the present status of Synergetics, emphasizing this time theoretical aspects, although the proceedings contain also important con­ tributions from the experimental side. Synergetics has ties to many quite different disciplines as is clearly mirrored by the following articles. Out of the many ties I pick here only one example which is alluded to in the title of this book. Indeed, there is an important branch of mathematics called dynamic systems theory for which the problems of Synergetics might become an eldorado. While, undoubtedly, a good deal of dynamic systems had been motivated by mechanics, such as celestial and fluid dynamics, theory Synergetics provides us with a wealth of related problems of quite different fields, e. g. , lasers or chemical reaction processes. In order to become adequately applicable, in quite a number of realistic cases dynamic systems theory must be developed further. This is equally true for a number of other approaches.

This book contains the invited papers of an international symposium on Synergetics which was held at ZIF (Center for interdisciplinary research) at Bielefeld. Fed. Rep. of Germany. Sept. 24. -29 . • 1979. In keeping with our previous meetings. this one was truly interdisciplinary. Synergetic systems are those that can produce macroscopic spatial. temporal or functional structures in a self-organized way. I think that these proceedings draw a rather coherent picture of the present status of Synergetics, emphasizing this time theoretical aspects, although the proceedings contain also important con­ tributions from the experimental side. Synergetics has ties to many quite different disciplines as is clearly mirrored by the following articles. Out of the many ties I pick here only one example which is alluded to in the title of this book. Indeed, there is an important branch of mathematics called dynamic systems theory for which the problems of Synergetics might become an eldorado. While, undoubtedly, a good deal of dynamic systems had been motivated by mechanics, such as celestial and fluid dynamics, theory Synergetics provides us with a wealth of related problems of quite different fields, e. g. , lasers or chemical reaction processes. In order to become adequately applicable, in quite a number of realistic cases dynamic systems theory must be developed further. This is equally true for a number of other approaches.

According to its definition, synergetics is concerned with the cooperation of indi­ vidual parts of a system that produces macroscopic temporal, spatial or functional structures. A good deal of the volumes published within this series dealt with the formation of truly macroscopic structures which we can s. ee with our eyes. A common scheme could be developed to understand the formation of many patterns through self-organization. In particular, we have to use concepts which go beyond conventio­ nal thermodynamics. New ideas became crucial. We have to study kinetic processes, and often few highly excited degrees of freedom play the decisive role in the evo­ lution of structures. Over the past years it has turned out that quite similar lines of approach apply to a world which at first sight would be classified as "microsco­ pic". That world consists of processes in which biomolecules are involved. An impor­ tant example for the problems occurring there is provided by Manfred Eigen''s theory of evolution of life at the molecular level (cf. his contribution to Volume 17 of this series). Another important example has been provided by Blumenfeld''s book on problems of biological physics (Vol. 7 of this series). There it was proposed to treat biological molecules as machines which, in a certain sense, work through "macros­ copic" degrees of freedom.

According to its definition, synergetics is concerned with the cooperation of indi­ vidual parts of a system that produces macroscopic temporal, spatial or functional structures. A good deal of the volumes published within this series dealt with the formation of truly macroscopic structures which we can s. ee with our eyes. A common scheme could be developed to understand the formation of many patterns through self-organization. In particular, we have to use concepts which go beyond conventio­ nal thermodynamics. New ideas became crucial. We have to study kinetic processes, and often few highly excited degrees of freedom play the decisive role in the evo­ lution of structures. Over the past years it has turned out that quite similar lines of approach apply to a world which at first sight would be classified as "microsco­ pic". That world consists of processes in which biomolecules are involved. An impor­ tant example for the problems occurring there is provided by Manfred Eigen's theory of evolution of life at the molecular level (cf. his contribution to Volume 17 of this series). Another important example has been provided by Blumenfeld's book on problems of biological physics (Vol. 7 of this series). There it was proposed to treat biological molecules as machines which, in a certain sense, work through "macros­ copic" degrees of freedom.

The study of cooperative phenomena is one of the dominant features of contem­ porary physics. Outside physics it has grown to a huge field of interdisciplinary investigation, involving all the natural sciences from physics via biology to socio­ logy. Yet, during the first few decades following the advent of quantum theory, the pursuit of the single particle or the single atom, as the case may be, has been so fascinating that only a small number of physicists have stressed the importance of collective behaviour. One outstanding personality among these few is Professor HERBERT FROHLICH. He has made an enormous contribution to the modern concept of cooperativity and has stimulated a whole generation of physicists. Therefore, it seemed to the editors very appropriate to dedicate a volume on "cooperative phenomena" to him on the occasion of his official retirement from his university duties. Nevertheless, in the course of carrying out this project, the editors have been somewhat amazed to find that they have covered the essentials of contemporary physics and its im­ pact on other scientific disciplines. It thus becomes clear how much HERBERT FROHLICH has inspired research workers and has acted as a stimulating discussion partner for others. FROHLICH is one of those exceptional scientists who have wor­ ked in quite different fields and given them an enormous impetus. Unfortunately, the number of scientists of such distinctive personality has been decreasing in our century.

The study of cooperative phenomena is one of the dominant features of contem­ porary physics. Outside physics it has grown to a huge field of interdisciplinary investigation, involving all the natural sciences from physics via biology to socio­ logy. Yet, during the first few decades following the advent of quantum theory, the pursuit of the single particle or the single atom, as the case may be, has been so fascinating that only a small number of physicists have stressed the importance of collective behaviour. One outstanding personality among these few is Professor HERBERT FROHLICH. He has made an enormous contribution to the modern concept of cooperativity and has stimulated a whole generation of physicists. Therefore, it seemed to the editors very appropriate to dedicate a volume on "cooperative phenomena" to him on the occasion of his official retirement from his university duties. Nevertheless, in the course of carrying out this project, the editors have been somewhat amazed to find that they have covered the essentials of contemporary physics and its im­ pact on other scientific disciplines. It thus becomes clear how much HERBERT FROHLICH has inspired research workers and has acted as a stimulating discussion partner for others. FROHLICH is one of those exceptional scientists who have wor­ ked in quite different fields and given them an enormous impetus. Unfortunately, the number of scientists of such distinctive personality has been decreasing in our century.