Magnetic Fields from the Electroweak Phase Transition

I review some of the mechanisms through which primordial magnetic fields may be created in the electroweak phase transition. I show that no magnetic fields are produced initially from two-bubble collisions in a first-order transition. The initial field produced in a three-bubble collision is computed. The evolution of fields at later times is discussed.Comment: Talk presented at the International Workshop on Particle Physics and the Early Universe (COSMO--97) in Ambleside, England, 15-19 Sept 1997. To appear in the proceedings (World Scientific). LaTeX, 5 page

The Origin of Cosmic Magnetic Fields

In this talk, I review a number of particle-physics models that lead to the creation of magnetic fields in the early universe and address the complex problem of evolving such primordial magnetic fields into the fields observed today. Implications for future observations of the Cosmic Microwave Background (CMB) are discussed. Focussing on first-order phase transitions in the early universe, I describe how magnetic fields arise in the collision of expanding true-vacuum bubbles both in Abelian and non-Abelian gauge theories.Comment: 9 pages, 1 figure, talk presented at the 3rd International Conference on Particle Physics and the Early Universe (COSMO-99), Trieste, Italy, 27 Sept - 3 Oct, 1999, to be published in the proceedings. Added reference

Cosmic Magnetic Fields from Particle Physics

I review a number of particle-physics models that lead to the creation of magnetic fields in the early universe and address the complex problem of evolving such primordial magnetic fields into the fields observed today. Implications for future observations of the Cosmic Microwave Background (CMB) are briefly discussed.Comment: 8 pages, 1 figure, talk presented at the 7th International Symposium on Particles, Strings and Cosmology (PASCOS-99) at Granlibakken, Lake Tahoe, 10-16 Dec 1999, to appear in the proceeding

CP Violating Solitons in the Early Universe

Solitons in extensions of the Standard Model can serve as localized sources of CP violation. Depending on their stability properties, they may serve either to create or to deplete the baryon asymmetry. The conditions for existence of a particular soliton candidate, the membrane solution of the two-Higgs model, are presented. In the generic case, investigated by Bachas and Tomaras, membranes exist and are metastable for a wide range of parameters. For the more viable supersymmetric case, it is shown that the present-day existence of CP-violating membranes is experimentally excluded, but preliminary studies suggest that they may have existed in the early universe soon after the electroweak phase transition, with important consequences for the baryon asymmetry of the universe.Comment: Talk given by Ola Tornkvist, to appear in the proceedings of Fundamental Physics at the Birth of the Universe, II, in Rome, Italy, 19-24 May 1997. Revtex, 7 pages, 1 postscript figure, uses epsf.tex, aps.sty, prl.sty, preprint.sty. Preprint number correcte

Baryon Number Non-Conservation and the Topology of Gauge Fields

An introduction to the subject of baryon number non-conservation in the electroweak theory at high temperatures or energies is followed by a summary of our discovery of an infinite surface of sphaleron-like configurations which play a key role in baryon-number non-conserving transitions in a hot electroweak plasma.Comment: Talk given by Ola Tornkvist, to appear in the proceedings of the meeting of the American Physical Society, Division of Particles and Fields (DPF 96) in Minneapolis, Minnesota, August 10-15, 1996. Plain latex, 6 page