Max-Planck-Gesellschaft

2017

2017, Max Planck Institute for Gravitational Physics

Nicolai, Hermann

General relativity theory and the standard model of particle physics describe physical phenomena correctly over a vast range of distances and are nevertheless incomplete. In order to understand what is happening inside a black hole or at the Big Bang, a new unified theory is sought which contains the standard model and the theory of gravitation as limiting cases, but whose mathematical contradictions are overcome. Maybe reflections on symmetry can help here.

2016

2016, Max Planck Institute for Gravitational Physics

Maliborski, Maciej; Schell, Christian

The stability of solutions to Einstein’s equations is essential for the physical interpretation. However, its investigations are mathematically challenging. The Anti-de Sitter space (AdS) is a frequently used solution in theoretical physics, even though only recently insights about its stability were achieved. This article reviews the current state of research concerning that question, in particular the coexistence of stable and instable regimes.

2015

2015, Max Planck Institute for Gravitational Physics

Siegel, Daniel

Short gamma-ray bursts are highly energetic flashes of gamma rays lasting less than two seconds. They are most likely produced by the merger of two neutron stars in a binary system and are among the most dramatic events observed in the Universe. Despite decades of scientific progress the detailed physical processes that generate these bursts still remain elusive. Recent numerical simulations on supercomputers, however, play a vital role in unraveling the nature of these bursts.

2015, Max Planck Institute for Gravitational Physics

Schlotterer, Oliver

Scattering amplitudes describe the interactions of elementary particles and form the foundations to predict the results of measurements. They exhibit significantly richer mathematical structures and symmetries as the conventional Feynman-diagram prescription for their computation gives rise to expect. In the subsequent, a formalism with additional symmetries and spatial dimensions is introduced which manifests the hidden elegance of scattering amplitudes and allows for an intuitive approach.

2014

2014, Max Planck Institute for Gravitational Physics

Rinne, Oliver

When solving Einstein's equations numerically, one faces the problem of treating an infinite asymptotically flat spacetime with finite computing resources. Here a decomposition of spacetime into hyperboloidal surfaces approaching lightlike infinity is considered. Upon compactification the Einstein equations develop formally singular terms, which can nevertheless be evaluated explicitly. Based on this method, stable numerical evolutions of spacetimes containing black holes and gravitational waves or matter fields have been achieved.

2013

2013, Max Planck Institute for Gravitational Physics

Babak, Stanislav; Jasiulek, Michael; Schutz, Bernard F.

The ground-based gravitational wave observatories, eLISA and pulsar timing arrays span a huge frequency range and probe very different sources of gravitational waves. As instruments are improved and the data analysis techniques become even more robust and sophisticated, detections become more and more likely. Conservatively, we expect a first detection of gravitational waves within the next 10 years, and it seems likely to happen in half that time.

2012

2012, Max Planck Institute for Gravitational Physics

Lehners, Jean-Luc

There are currently two theories that can explain both the homogeneity of the universe and the temperature fluctuations in the cosmic background radiation: inflation and the cyclic universe. Both models however lead to different predictions regarding the fine details of the distributions of these temperature fluctuations, so that upcoming data will be able to distinguish between them. According to string theory, both types of universe should be physically realised. This begs the question of whether one can already predict on a theoretical level which type of universe we are likely to inhabit.

2011

2011, Max Planck Institute for Gravitational Physics

Andersson, Lars

Einstein's theory of general relativity gives a description of gravitating systems like stars and black holes. For simple systems such as a time-independent and rotating black hole, exact and explicit solutions to the field equations of general relativity are known. It is of great interest to investigate whether these solutions are dynamical stable, i. e., if the small changes in the initial data lead to solutions with similar properties, since it is only then, that the exact and explicitly known solutions can be said to be physically relevant.

2010

2010, Max Planck Institute for Gravitational Physics

Amaro Seoane, Pau

Nowadays it is well-established that in the centre of the Milky Way a massive black hole (MBH) with a mass of about four million solar masses is lurking. While we start to have a defined picture about the origin and growth of supermassive black holes, MBHs with smaller masses such as the one in our galactic centre remain an understudied enigma. The key to understanding these holes, and how some of them grow by orders of magnitude in mass, is to understand the dynamics of the stars in the galactic neighbourhood.

2010, Max Planck Institute for Gravitational Physics

Schuller, Frederic P.

Definitive conclusions may be drawn occasionally even from incomplete information. Indeed, employing a remarkable interplay between various areas of modern mathematics, one is able to discuss the entire class of spacetime geometries that may serve as backgrounds for the consistent propagation of matter. Such generalized geometries emerge from theories of quantum gravity, but also provide a far-reaching geometric point of view to the spectacular experimental observation that our universe expands at an accelerated rate.

2009

2009, Max Planck Institute for Gravitational Physics

Ansorg, Marcus

This article is concerned with models of rotating bodies which are composed of fluid matter and whose internal structure is determined to a great extent by its own gravitational field. In particular, these models exhibit an equilibrium between attracting gravitational forces, repelling pressure and centrifugal forces. By virtue of this balance of forces the body takes on a typical shape: a figure of equilibrium. In the following it is described which principle physical and mathematical aspects arise and, moreover, the complexity of this field is demonstrated by means of a number of examples.

2008

2008, Max Planck Institute for Gravitational Physics

Theisen, Stefan; Pössel, Markus

String theory is a central player in our search for a consistent theory of quantum gravity. The theory forces us to re-evaluate familiar conceptions of space and time. In the following article this shall be illustrated with examples.

2008, Max Planck Institute for Gravitational Physics

Whelan, John T.

A new generation of gravitational wave observatories offers the possibility for the first direct detection of gravitational waves. LIGO, the Laser Interferometric Gravitational Wave Observatory, has completed its two-year-long fifth science run (“S5”), the first at its design sensitivity, and preliminary results from the analysis of S5 data are producing new information about astrophysical phenomena.

2007

2007, Max Planck Institute for Gravitational Physics

Rendall, Alan D.

This article describes recent developments in cosmology, in particular those connected with a certain curve (referred to here as 'icon') which arises from observations of the cosmic microwave background radiation. In this context it is explained how scientists try to get a better theoretical understanding of this curve and other questions in science with the aid of mathematics, especially analysis and geometry.

2006

2006, Max Planck Institute for Gravitational Physics

Rezzolla, Luciano; Baiotti, Luca; Ott, Christian David; Pollney, Denis

The numerical relativity group at the Albert Einstein Institute has recently made important contributions to the solution of the Einstein equations in regimes in which no analytic approach is possible, such as the death of a star, the birth of a black hole or the fate of a binary system of black holes.

2006, Max Planck Institute for Gravitational Physics

Kleinschmidt, Axel

We present a novel definition of a unified theory of all four known fundamental forces. This definition was developed at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI) and utilizes new results concerning the symmetry structures of string theory.

2005

2005, Max Planck Institute for Gravitational Physics

Grüneberg, Michel

This paper is a heuristic introduction into current mathematical research in differential geometry, which provided the basic framework for formulating Einstein’s theory of General Relativity. Specifically, recent results in the field of geometric evolution equations are described, which concern the so-called Yamabe flow.

2004

2004, Max Planck Institute for Gravitational Physics

Aulbert, Carsten

Between the construction start of GEO600 in 1995 and the preliminary end of construction in 2003 there have been several years of exciting development of a new instrument to explore the universe. With the data taken during the first scientific data run (S1) it is now possible to set upper limits on the strength of gravitational waves from rotating neutron stars for the first time.

2004, Max Planck Institute for Gravitational Physics

Staudacher, Matthias

We explain a novel approach to the study of four-dimensional quantum field theories using long-range, integrable super-spinchains, which was recently developed at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute). It allows deep insights into the nature of superstring theory.