Euclidean solutions of Yang-Mills-dilaton theory

Classical solutions of the Yang-Mills-dilaton theory in Euclidean space-time are investigated. Our analytical and numerical results imply existence of infinite number of branches of dyonic type solutions labelled by the number of nodes of gauge field amplitude $W$. We find that the branches of solutions exist in finite region of parameter space and discuss this issue in detail in different dilaton field normalization.Comment: 16 pages, 11 figures, references added, matches published vesio

On instability of Rubakov-Shaposhnikov model

Instability of 6 dimensional Rubakov-Shaposhnikov model is reinvestigated. It is shown that the model is unstable in scalar perturbations sector with very particular instability pattern: there are no unstable modes for the first two lowest angular harmonics, m=0 and m=1, whereas there is a single negative mode for each higher m.Comment: 7 pages, including 1 figur

Gravitating, Gravitational and Dilatonic Sphalerons

This is a brief review of the main properties of sphalerons in various theories with a Yang--Mills field. Talk given at the Heat Kernel Techniques and Quantum Gravity, Winnipeg, Canada, August 2-6, 1994.Comment: 12 pages, Te

Negative mode problem in false vacuum decay with gravity

There is a single negative mode in the spectrum of small perturbations about the tunneling solutions describing a metastable vacuum decay in flat spacetime. This mode is needed for consistent description of decay processes. When gravity is included the situation is more complicated. An approach based on elimination of scalar field perturbations shows no negative mode, whereas the recent approach based on elimination of gravitational perturbations indicates presence of a negative mode. In this contribution we analyse and compare the present approaches to the negative mode problem in false vacuum decay with gravity.Comment: 8 pages, 1 eps figure, Talk given at Constrained Dynamics and Quantum Gravity 99, Villasimius, (Sardinia, Italy), September 14-18, 1999. To apper in the Proceedings. After this contribution was essentially completed, further progress in investigation of negative mode problem was made. The results are summarized in the revised version of gr-qc/000104