Martin Bojowald – författare

In 2000, Martin Bojowald, then a twenty-seven-year-old post-doc at Pennsylvania State University, used a relatively new theory called loop quantum gravity—a cunning combination of Einstein’s theory of gravity with quantum mechanics—to create a simple model of the universe. Loop quantum cosmology was born, and with it, a theory that managed to do something even Einstein’s general theory of relativity had failed to do—illuminate the very birth of the universe.Ever since, loop quantum cosmology, or LQC, has been tantalizing physicists with the idea that our universe could conceivably have emerged from the collapse of a previous one. Now the theory is poised to formulate hypotheses we can actually test. If they are verified, the big bang will give way to the big bounce. Instead of a universe that emerged from a point of infinite density, we will have one that recycles, possibly through an eternal series of expansions and contractions, with no beginning and no end.Bojowald’s major realization was that unlike general relativity, the physics of LQC do not break down at the big bang. The greatest mystery surrounding the origin of the universe is what cosmologists call the big bang “singularity”—the point at the beginning of the universe, prior to the existence of space and time, when gravity, along with the temperature and density of the universe, becomes infinite. The equations of general relativity can’t cope with such infinities, and as a result big bang theory has never been able to give any explanation for the initial condition of our universe, succeeding only in describing and explaining the evolution of the universe from that instant onward. Bojowald’s theory takes us right up to the first moment of the universe—and then back, even before the big bang itself.From the Hardcover edition.

This book presents the two foundational pillars of modern physics, quantum mechanics and general relativity, in a coherent form aimed primarily at upper-level undergraduate students. It provides a unified picture of the underlying field of mathematical physics and the fruitful interactions between different methods and applications. To help students navigate both topics, the book takes a systematic, pedagogical and uniform approach to the underlying theories and applications. This includes detailed discussions of applications, such as in atomic and particle physics, measurements of space and time, black holes and cosmology.Fundamental Physics: A Guide to Relativity and Quantum Theory is essential for upper-level undergraduate students looking to develop a cohesive understanding of the ways in which quantum mechanics and general relativity are central not only to the challenges and approaches to quantum theories of gravity but also to gravitational implications on sensitive quantum effects. Worked examples and homework problems are available throughout.Key Features:This class-tested textbook combines two fundamental topics in modern physics: quantum mechanics and general relativityDetailed conceptual discussions of physics insights are combined with careful mathematical constructionsWorked examples are available throughoutChapter-end homework problems are also included

This book presents the two foundational pillars of modern physics, quantum mechanics and general relativity, in a coherent form aimed primarily at upper-level undergraduate students. It provides a unified picture of the underlying field of mathematical physics and the fruitful interactions between different methods and applications. To help students navigate both topics, the book takes a systematic, pedagogical and uniform approach to the underlying theories and applications. This includes detailed discussions of applications, such as in atomic and particle physics, measurements of space and time, black holes and cosmology.Fundamental Physics: A Guide to Relativity and Quantum Theory is essential for upper-level undergraduate students looking to develop a cohesive understanding of the ways in which quantum mechanics and general relativity are central not only to the challenges and approaches to quantum theories of gravity but also to gravitational implications on sensitive quantum effects. Worked examples and homework problems are available throughout.Key Features: This class-tested textbook combines two fundamental topics in modern physics: quantum mechanics and general relativity Detailed conceptual discussions of physics insights are combined with careful mathematical constructions Worked examples are available throughout Chapter-end homework problems are also included

This book presents the two foundational pillars of modern physics, quantum mechanics and general relativity, in a coherent form aimed primarily at upper-level undergraduate students. It provides a unified picture of the underlying field of mathematical physics and the fruitful interactions between different methods and applications. To help students navigate both topics, the book takes a systematic, pedagogical and uniform approach to the underlying theories and applications. This includes detailed discussions of applications, such as in atomic and particle physics, measurements of space and time, black holes and cosmology.Fundamental Physics: A Guide to Relativity and Quantum Theory is essential for upper-level undergraduate students looking to develop a cohesive understanding of the ways in which quantum mechanics and general relativity are central not only to the challenges and approaches to quantum theories of gravity but also to gravitational implications on sensitive quantum effects. Worked examples and homework problems are available throughout.Key Features: This class-tested textbook combines two fundamental topics in modern physics: quantum mechanics and general relativity Detailed conceptual discussions of physics insights are combined with careful mathematical constructions Worked examples are available throughout Chapter-end homework problems are also included

Consequences of quantum gravity on grander scales are expected to be enormous: only such a theory can show how black holes really behave and where our universe came from. Applications of loop quantum gravity to cosmology have especially by now shed much light on cosmic evolution of a universe in a fundamental, microscopic description. Modern techniques are explained in this book which demonstrate how the universe could have come from a non-singular phase before the big bang, how equations for the evolution of structure can be derived, but also what fundamental limitations remain to our knowledge of the universe before the big bang.The following topics will be covered in this book:Hamiltonian cosmology: a general basic treatment of isotropy, perturbations and their role for observations; useful in general cosmology.Effective equations: an efficient way to evaluate equations of quantum gravity, which is also useful in other areas of physics where quantum theory is involved.Loop quantization: a new formalism for the atomic picture of space-time; usually presented at a sophisticated mathematical level, but evaluated here from an intuitive physical side.The book will start with physical motivations, rather than mathematical developments which is more common in other expositions of this field. All the required mathematical methods will be presented, but will not distract the reader from seeing the underlying physics. Simple but representative models will be presented first to show the basic features, which are then used to work upwards to a general description of quantum gravity and its applications in cosmology. This will make the book accessible to a more general physics readership.

Consequences of quantum gravity on grander scales are expected to be enormous: only such a theory can show how black holes really behave and where our universe came from. Applications of loop quantum gravity to cosmology have especially by now shed much light on cosmic evolution of a universe in a fundamental, microscopic description. Modern techniques are explained in this book which demonstrate how the universe could have come from a non-singular phase before the big bang, how equations for the evolution of structure can be derived, but also what fundamental limitations remain to our knowledge of the universe before the big bang.The following topics will be covered in this book:Hamiltonian cosmology: a general basic treatment of isotropy, perturbations and their role for observations; useful in general cosmology.Effective equations: an efficient way to evaluate equations of quantum gravity, which is also useful in other areas of physics where quantum theory is involved.Loop quantization: a new formalism for the atomic picture of space-time; usually presented at a sophisticated mathematical level, but evaluated here from an intuitive physical side.The book will start with physical motivations, rather than mathematical developments which is more common in other expositions of this field. All the required mathematical methods will be presented, but will not distract the reader from seeing the underlying physics. Simple but representative models will be presented first to show the basic features, which are then used to work upwards to a general description of quantum gravity and its applications in cosmology. This will make the book accessible to a more general physics readership.

Der spektakuläre Blick in das Universum vor dem »big bang«!Bislang blieb der »Urknall« die letzte Grenze, hinter die kein Physiker zurück konnte. Selbst für die Allgemeine Relativitätstheorie gilt dieser Zeitpunkt als »Singularität«, die sich nicht mehr mit ihren Gleichungen berechnen lässt und wo die physikalischen Gesetzmäßigkeiten nicht mehr definiert sind. Hier beginnt für uns das Universum. Doch was war vorher?Der junge Physiker Martin Bojowald hat in der Fachwelt Aufsehen erregt, weil es ihm mit einer Reihe von Gleichungen gelungen ist, näher als jemals bisher an den Urknall heranzukommen und sogar darüber hinaus. Plötzlich ist sind Einblicke in das möglich geworden, was vor dem Urknall war – mit verblüffenden Erkenntnissen über eine aufregend unbekannte Welt mit negativer Zeit, »umgestülpten Raumverhältnissen« und einem Kosmos, der sich zusammenzieht, um nach dem »Big Bang« zu expandieren. Alte kosmologische Modelle über den Zyklus des Werdens und Vergehens des Weltalls erhalten dadurch eine ganz neue Aktualität. Doch wie war es wirklich? Was war »vor dem Urknall«?In seinem Buch »Zurück vor den Urknall« erklärt Martin Bojowald anschaulich und ohne jede Formel die physikalischen Hintergründe seiner Theorie. Er nimmt seine Leser mit auf eine spannende Reise durch die heutige Kosmologie, zurück zum Ursprung des Universums – und in die Zeit davor.

Written by a well-known author in the field, this book presents a modern understanding of the universe based on relativity, quantum physics and their elusive combination. It introduces the crucial theoretical ingredients in an accessible way, starting from the physics of Newton and developing subsequent theories all the way to the modern enigma of quantum gravity. The intermediate level presentation assumes only a general knowledge of math and physics, adopting a "two-level" approach: equations are retained throughout the chapters but set apart from the main text in boxes to allow for lay readers to understand the book. For scientists, researchers, students and lecturers in cosmology, astronomy, gravitation, quantum and theoretical physics; as well as mathematicians, students, lecturers, academics and non-experts in related fields with an interest in the subject.

Written by a well-known author in the field, this book presents a modern understanding of the universe based on relativity, quantum physics and their elusive combination. It introduces the crucial theoretical ingredients in an accessible way, starting from the physics of Newton and developing subsequent theories all the way to the modern enigma of quantum gravity. The intermediate level presentation assumes only a general knowledge of math and physics, adopting a "two-level" approach: equations are retained throughout the chapters but set apart from the main text in boxes to allow for lay readers to understand the book. For scientists, researchers, students and lecturers in cosmology, astronomy, gravitation, quantum and theoretical physics; as well as mathematicians, students, lecturers, academics and non-experts in related fields with an interest in the subject.