2008BrandtDPhD.pdf (1.97 MB)
Superconducting Detectors and Massive Gauge Bosons in Superconductivity
thesisposted on 2010-07-12, 11:09 authored by Daniel Brandt
This thesis is concerned with the fundamental physics of the superconducting-to-normal transition (sn-transition), particularly the mechanisms which give rise to massive gauge bosons and applications of the superconducting-to-normal transition, particularly in the form of superconducting radiation detectors.The basics of three of the most common types of superconducting particle detectors are discussed in Chapter 2: Superconducting Tunnel Junctions (STJs), Transition Edge Sensors (TESs), and Metallic Magnetic Calorimeters (MMCs). The chapter continues with an investigation of the phenomenon of TES excess noise, a white noise source of uncertain origin apparently intrinsic to the device . The current theories of Phase Slip Shot Noise (PSSN) and percolation noise are discussed and the quantitative analytical model proposed by Fraser  is extended to include the magnetic field dependence of the noise spectral current density. An analytical expression for the dependence of the percolation noise spectral current density on experimental parameters is derived. In Chapter 3 the author addresses the question of whether quantum mechanical fluctuations of the vacuum energy can influence the sn-transition. The existing theory is refined by developing a treatment of the system using superconductor-specific electrodynamics. A mathematical model of the relevant vacuum interactions is derived and a quantitative estimate of the magnitude of the coupling is presented. In superconductors photons have a non-zero rest mass arising from the Higgs mechanism. Chapter 4 discusses the optical properties of a hypothetical transparent superconductor and finds practical applications. In Chapter 5 it is found that the Higgs mechanism applies to any gauge field generated by the superconducting electrons, including their gravitational field and a theory of massive gravity is developed. The massive gravitational field is propagated by non-zero rest mass gravitons, and the theory predicts the sum of gravitomagnetic flux and magnetic flux through a superconducting ring to be quantised. Some of the implications and possible experiments are explored.
Date of award2009-01-19
Awarding institutionUniversity of Leicester