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Magnetic monopole creation

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Title: Magnetic monopole creation
Authors: Gould, Oliver
Item Type: Thesis or dissertation
Abstract: Elementary magnetic monopoles have never been experimentally observed but there are credible theoretical reasons to believe that they may nonetheless exist. This thesis gives partial answers to the questions: if magnetic monopoles do exist, can we create them? And if so, how? Surprisingly little is known about the answers to these simple-sounding questions. The fundamental stumbling block is the strong coupling of magnetic monopoles. This prevents the usual arsenal of techniques from being used, which have proved so useful in understanding the creation of everything from electrons to Higgs particles to quarks. I consider magnetic monopole creation in strong magnetic fields and at high temperatures. I show that the semiclassical approximation is valid, despite the strong coupling, and calculate the rate using the worldline formalism. The leading order results suggest that magnetic monopoles will be created amply above a certain threshold magnetic field strength and temperature. This is independent of many details of the particles, in particular their spin and whether they are elementary or composite. Strong magnetic fields and high temperatures are present in neutron stars and in terrestrial heavy ion collisions. By comparison with known properties of neutron stars, and with a search for magnetic monopoles at CERN, I derive the strongest yet, model-independent bounds on the mass of any possible magnetic monopoles. However, investigating higher order corrections to my results, I encounter an instability in the equations which casts doubt on the validity of my approximations and hence the mass bounds. In answer to my questions: if magnetic monopoles do exist, we may be able to create them in sufficiently high energy heavy ion collisions. However, more theoretical work is needed to decide upon this, both to overcome the issue of the instability and to understand the effects of the spacetime evolution of such collisions.
Content Version: Open Access
Issue Date: Sep-2017
Date Awarded: Mar-2018
URI: http://hdl.handle.net/10044/1/67609
DOI: https://doi.org/10.25560/67609
Supervisor: Rajantie, Arttu
Sponsor/Funder: Science and Technology Facilities Council (Great Britain)
Department: Physics
Publisher: Imperial College London
Qualification Level: Doctoral
Qualification Name: Doctor of Philosophy (PhD)
Appears in Collections:Physics PhD theses

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