Citation
Marković, Dragoljub (1994) Black holes in the early universe, in compact binaries, and as energy sources inside solartype stars. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ms5qkt36. https://resolver.caltech.edu/CaltechTHESIS:05092013084229368
Abstract
This thesis consists of three separate studies of roles that black holes might play in our universe.
In the first part we formulate a statistical method for inferring the cosmological parameters of our universe from LIGO/VIRGO measurements of the gravitational waves produced by coalescing blackhole/neutronstar binaries. This method is based on the cosmological distanceredshift relation, with "luminosity distances" determined directly, and redshifts indirectly, from the gravitational waveforms. Using the current estimates of binary coalescence rates and projected "advanced" LIGO noise spectra, we conclude that by our method the Hubble constant should be measurable to within an error of a few percent. The errors for the mean density of the universe and the cosmological constant will depend strongly on the size of the universe, varying from about 10% for a "small" universe up to and beyond 100% for a "large" universe. We further study the effects of random gravitational lensing and find that it may strongly impair the determination of the cosmological constant.
In the second part of this thesis we disprove a conjecture that black holes cannot form in an early, inflationary era of our universe, because of a quantumfieldtheory induced instability of the blackhole horizon. This instability was supposed to arise from the difference in temperatures of any blackhole horizon and the inflationary cosmological horizon; it was thought that this temperature difference would make every quantum state that is regular at the cosmological horizon be singular at the blackhole horizon. We disprove this conjecture by explicitly constructing a quantum vacuum state that is everywhere regular for a massless scalar field. We further show that this quantum state has all the nice thermal properties that one has come to expect of "good" vacuum states, both at the blackhole horizon and at the cosmological horizon.
In the third part of the thesis we study the evolution and implications of a hypothetical primordial black hole that might have found its way into the center of the Sun or any other solartype star. As a foundation for our analysis, we generalize the mixinglength theory of convection to an optically thick, spherically symmetric accretion flow (and find in passing that the radial stretching of the inflowing fluid elements leads to a modification of the standard Schwarzschild criterion for convection). When the accretion is that of solar matter onto the primordial hole, the rotation of the Sun causes centrifugal hangup of the inflow near the hole, resulting in an "accretion torus" which produces an enhanced outflow of heat. We find, however, that the turbulent viscosity, which accompanies the convective transport of this heat, extracts angular momentum from the inflowing gas, thereby buffering the torus into a lower luminosity than one might have expected. As a result, the solar surface will not be influenced noticeably by the torus's luminosity until at most three days before the Sun is finally devoured by the black hole. As a simple consequence, accretion onto a black hole inside the Sun cannot be an answer to the solar neutrino puzzle.
Item Type:  Thesis (Dissertation (Ph.D.)) 

Subject Keywords:  Physics 
Degree Grantor:  California Institute of Technology 
Division:  Physics, Mathematics and Astronomy 
Major Option:  Physics 
Thesis Availability:  Public (worldwide access) 
Research Advisor(s): 

Group:  TAPIR, Astronomy Department 
Thesis Committee: 

Defense Date:  28 February 1994 
Record Number:  CaltechTHESIS:05092013084229368 
Persistent URL:  https://resolver.caltech.edu/CaltechTHESIS:05092013084229368 
DOI:  10.7907/ms5qkt36 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided. 
ID Code:  7688 
Collection:  CaltechTHESIS 
Deposited By:  John Wade 
Deposited On:  09 May 2013 16:04 
Last Modified:  16 Apr 2021 23:32 
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