Norbert Straumann

General relativity and relativistic astrophysics

This study edition, which concentrates on the physical content of Einsteins theory of relativity, is intended for students of physics, astrophysics and mathematics. The mathematical background of modern differential geometry is kept to a minimum and serves mainly as a reference for the reader unfamiliar with Cartans co-ordinate-free calculus, which is used throughout the text. The author discusses the equivalence principle and the field equations together with their experimental support by recent observations. The book concludes with an analysis of modern astrophysics. It analyzes the Kerr-Newman solutions, gravitational collapse, the cooling of neutron stars, radio sources and black holes.

Instability of a colored black hole solution

We analyze the stability of a black hole solution of the Einstein-Yang-Mills equations that was recently found numerically by Bizon, and which provides a counter example for the “no hair” conjecture for non-abelian black holes. In the framework of small time-dependent perturbations it is shown that there is at least one exponentially growing radial mode with the correct boundary conditions at the horizon and at infinity.

New black hole solutions with hair

Abstract We present new black hole solutions which provide counter examples to the “no hair” conjecture for non-linear matter fields. These have been found numerically for the non-linear sigma-model of Skyrme coupled to gravity. They are static and approach asymptotically the Schwarzschild solution, but have “Skyrme hair”. We also describe self-gravitating generalizations of the well-known Skyrme solitons in flat spacetime. Both types of solutions are presumably stable.

Instability of the Bartnik-mckinnon Solution of the Einstein {Yang-Mills} Equations

Abstract We analyse the stability of the (ground state) Bartnik-McKinnon solution of the Einstein-Yang-Mills equations in the frame-work of small time-dependent perturbations. It is shown that the frequency spectrum of a class of radial perturbations is determined by the spectrum of a radial p-wave Schrodinger equation with a bounded effective potential. Bound states of this Schrodinger equation correspond to exponentially growing radial modes and it turns out that there is exactly one such bound state.

The number of sphaleron instabilities of the Bartnik-McKinnon solitons and non-Abelian black holes

Abstract It is proven that there are precisely n odd-parity sphaleron-like unstable modes of the n-th Bartnik-McKinnon solition and the n-th non-abelian black hole solution of the Einstein-Yang-Mills theory for the gauge group SU(2).It is proven that there are precisely

Stability analysis of self-gravitating skyrmions

n

DARK ENERGY: RECENT DEVELOPMENTS

odd-parity sphaleron-like unstable modes of the

Linear stability of Einstein-Skyrme black holes

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The Positive Mass Theorem

-th Bartnik-McKinnon soliton and the

Nonlinear perturbations of Einstein-Yang-Mills solitons and non-abelian black holes

n