arXiv subjects

Helia Hollmann

Publications and source records attributed to Helia Hollmann.

3 recordsLinked to original sources

arXiv1996

A Harmonic Space Approach to Spherically Symmetric Quantum Gravity

After dimensional reduction the stationary spherically symmetric sector of Einstein's gravity is identified with an SL(2,R)/SO(2) Sigma model coupled to a one dimensional gravitational remnant. The space of classical solutions consists of a one parameter family interpolating between the Schwarzschild and the Taub-NUT solution. A Dirac Quantization of this system is performed and the observables -- the Schwarzschild mass and the Taub-NUT charge operator -- are shown to be self-adjoint operators with a continuous spectrum ranging from $-\infty$ to $\infty$. The Hilbert space is constructed explicitely using a harmonic space approach.

gr-qc↗

arXiv1996

Group Theoretical Quantization of Schwarzschild and Taub-NUT

Stationary spherically symmetric gravity is equivalent to a nonlinear coset sigma model on SL(2,R)/SO(2) coupled to a gravitational remnant. Classically there are stationary solutions besides the static Schwarzschild metric labeled by the Schwarzschild mass $m$ and the Taub-NUT charge $l$. Imposing the SL(2,R) symmetry at the quantum level the Wheeler-DeWitt equation becomes related to the Casimir operator on the coset, which makes the system amenable to exact quantization.

gr-qc↗

arXiv1994

On the Stability of Gravitating Nonabelian Monopoles

The behaviour of magnetic monopole solutions of the Einstein-Yang-Mills-Higgs equations subject to linear spherically symmetric perturbations is studied. Using Jacobi's criterion some of the monopoles are shown to be unstable. Furthermore the numerical results and analytical considerations indicate the existence of a set of stable solutions.

gr-qc↗