Ugo Moschella – författare

Analogue Gravity Phenomenology is a collection of contributions that cover a vast range of areas in physics, ranging from surface wave propagation in fluids to nonlinear optics. The underlying common aspect of all these topics, and hence the main focus and perspective from which they are explained here, is the attempt to develop analogue models for gravitational systems. The original and main motivation of the field is the verification and study of Hawking radiation from a horizon: the enabling feature is the possibility to generate horizons in the laboratory with a wide range of physical systems that involve a flow of one kind or another. The years around 2010 and onwards witnessed a sudden surge of experimental activity in this expanding field of research. However, building an expertise in analogue gravity requires the researcher to be equipped with a rather broad range of knowledge and interests. The aim of this book is to bring the reader up to date with the latest developments and provide the basic background required in order to appreciate the goals, difficulties, and success stories in the field of analogue gravity.

Each chapter of the book treats a different topic explained in detail by the major experts for each specific discipline. The first chapters give an overview of black hole spacetimes and Hawking radiation before moving on to describe the large variety of analogue spacetimes that have been proposed and are currently under investigation. This introductory part is then followed by an in-depth description of what are currently the three most promising analogue spacetime settings, namely surface waves in flowing fluids, acoustic oscillations in Bose-Einstein condensates and electromagnetic waves in nonlinear optics. Both theory and experimental endeavours are explained in detail. The final chapters refer to other aspects of analogue gravity beyond the study of Hawking radiation, such as Lorentz invariance violations and Brownian motion in curved spacetimes, before concluding with a return to the origins of the field and a description of the available observational evidence for horizons in astrophysical black holes.

This book presents an overview of the current understanding of gravitation, with a focus on the current efforts to test its theory, especially general relativity. It shows how the quest for a deeper theory, which would possibly incorporate gravity in the quantum realm, is more than ever an open field.

The majority of the contributions deals with the manifold facets of “experimental gravitation”, but the book goes beyond this and covers a broad range of subjects from the foundations of gravitational theories to astrophysics and cosmology.

The book is divided into three parts. The first part deals with foundations and Solar System tests. An introductory pedagogical chapter reviews first Newtonian gravitational theory, special relativity, the equivalence principle and the basics of general relativity. Then it focuses on approximation methods, mainly the post-Newtonian formalism and the relaxed Einstein equations, with a discussion on how they are used in treating experimental tests and in the problem of generation and detection of gravitational waves. Following this is a set of chapters describing the most recent experiments, techniques and observations on the testing   of gravity theories in the laboratory, around the Earth and in the Solar System.

The second part is dedicated to astrophysical topics deeply linked with the study of gravitation, namely binary pulsars and the perspective of direct detection of gravitational waves. These cases are paradigmatic in that the gravitational signals act at the same time as messengers helping us to understand the properties of important and wide classes of astrophysical objects.

 The third part explores the many open issues in current knowledge of gravitation machinery, especially related to astrophysical and cosmological problems and the way possible solutions to them impact the quest for a quantum theory of gravitation and unified theory. Included is a selection of the many possiblepaths, giving a hint to the subtleties one is called upon. Whenever possible, a close link to observational constraints and possible experimental tests is provided.

 In selecting the topics of the various contributions, particular care has been devoted to ensure their fit in a coherent representation of our understanding of gravitational phenomena. The book is aimed at graduate level students and will form a valuable reference for those working in the field.

Jacques Bros has greatly advanced our present understanding of rigorous quantum field theory through numerous fundamental contributions. The impact of his work is also visible in several articles in this book. Quantum fields are considered as genuine mathematical objects, whose various properties and relevant physical interpretations have to be studied in a well-defined mathematical framework.

Key topics: Analytic structures of QFT, renormalization group methods, gauge QFT, stability properties and extension of the axiomatic framework, QFT on models of curved spacetimes, QFT on noncommutative Minkowski spacetime.