The first three microseconds: Cosmic strings, axions and magnetic fields
The dynamics of local cosmic strings are discussed in chapter one. The gravitational back-reaction problem and its relevance to kinks and cusps, as well as its implications for cosmic string networks, gravitational radiation and large-scale structure formation, are treated in depth. Cusps survive the backreaction. The decay time of a kink of size l, t(l)(sub decay) is found to be approximately ((gamma (sub kink)(G)(mu)) exp(-1))l where gamma (sub kink) is approximately 50. Kink decay times together with millisecond pulsar timing measurements yield an upper limit to the string tension, namely, G mu is less than 6 x 10 (exp -5). This is far from ruling out the cosmic string scenario of galaxy formation. The issue of divergences in global strings is resolved in chapter two, using a renormalization technique similar to that first used by Dirac for the classical electron. It is found that the motion of large global strings is very similar to that of local strings, and that as a consequence the axion mass is greater than 10(exp -3) eV. This lower bound is marginally inconsistent with an upper bound derived from SN1987a constraints; effectively the axion is ruled out as a cosmologically important dark matter candidate. The electrodynamics of the quantum chromodynamics (QCD) phase transition are dealt with in chapter three, which is assumed to be first order. Because of temperature gradients during the nucleation of hadron bubbles in the quark-gluon plasma, a thermoelectric Biermann battery is created during the transition. It is found that magnetic fields of size 10(exp -17) gauss will be present on A.U. scales during the epoch of galaxy formation. These fields may be the seeds required by dynamo theories of galactic magnetic fields.
- Research Organization:
- Princeton Univ., NJ (USA)
- OSTI ID:
- 6032352
- Resource Relation:
- Other Information: Ph.D. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
GALACTIC EVOLUTION
STRING MODELS
BOSONS
ELEMENTARY PARTICLES
GRAVITATIONAL FIELDS
INTERSTELLAR MAGNETIC FIELDS
MATHEMATICAL MODELS
PHASE TRANSFORMATIONS
QUANTUM CHROMODYNAMICS
QUANTUM ELECTRODYNAMICS
TEMPERATURE GRADIENTS
THEORETICAL DATA
COMPOSITE MODELS
DATA
ELECTRODYNAMICS
EXTENDED PARTICLE MODEL
FIELD THEORIES
INFORMATION
MAGNETIC FIELDS
NUMERICAL DATA
PARTICLE MODELS
QUANTUM FIELD THEORY
QUARK MODEL
640106* - Astrophysics & Cosmology- Cosmology