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http://hdl.handle.net/11375/12392
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DC Field | Value | Language |
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dc.contributor.advisor | Burgess, Cliff | en_US |
dc.contributor.author | Horbatsch, Michael W. | en_US |
dc.date.accessioned | 2014-06-18T16:59:26Z | - |
dc.date.available | 2014-06-18T16:59:26Z | - |
dc.date.created | 2012-08-15 | en_US |
dc.date.issued | 2012-10 | en_US |
dc.identifier.other | opendissertations/7284 | en_US |
dc.identifier.other | 8302 | en_US |
dc.identifier.other | 3221165 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/12392 | - |
dc.description.abstract | <p>The properties of neutron stars and black holes are investigated within a class of alternative theories of gravity known as Scalar-Tensor theories, which extend General Relativity by introducing additional light scalar fields to mediate the gravitational interaction.</p> <p>It has been known since 1993 that neutron stars in certain Scalar-Tensor theories may undergo ‘scalarization’ phase transitions. The Weak Central Coupling (WCC) expansion is introduced for the purpose of describing scalarization in a perturbative manner, and the leading-order WCC coefficients are calculated analytically for constant-density stars. Such stars are found to scalarize, and the critical value of the quadratic scalar-matter coupling parameter β<sub>s</sub> = −4.329 for the phase transition is found to be similar to that of more realistic neutron star models.</p> <p>The influence of cosmological and galactic effects on the structure of an otherwise isolated black hole in Scalar-Tensor gravity may be described by incorporating the Miracle Hair Growth Formula discovered by Jacobson in 1999, a perturbative black hole solution with scalar hair induced by time-dependent boundary conditions at spatial infinity. It is found that a double-black-hole binary (DBHB) subject to these boundary conditions is inadequately described by the Eardley Lagrangian and emits scalar dipole radiation.</p> <p>Combining this result with the absence of observable dipole radiation from quasar OJ287 (whose quasi-periodic ‘outbursts’ are consistent with the predictions of a general-relativistic DBHB model at the 6% level) yields the bound |φ/Mpl| < (16 days)<sup>-1</sup> on the cosmological time variation of canonically-normalized light (m < 10<sup>−23</sup> eV) scalar fields at redshift z ∼ 0.3.</p> | en_US |
dc.subject | Scalar-Tensor Gravity | en_US |
dc.subject | Scalar Hair | en_US |
dc.subject | Stellar Structure | en_US |
dc.subject | Spontaneous Scalarization | en_US |
dc.subject | Double Black Hole Binaries | en_US |
dc.subject | Quasar OJ287 | en_US |
dc.subject | Cosmology, Relativity, and Gravity | en_US |
dc.subject | Elementary Particles and Fields and String Theory | en_US |
dc.subject | Cosmology, Relativity, and Gravity | en_US |
dc.title | NEUTRON STARS AND BLACK HOLES IN SCALAR-TENSOR GRAVITY | en_US |
dc.type | thesis | en_US |
dc.contributor.department | Physics and Astronomy | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
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fulltext.pdf | 543.04 kB | Adobe PDF | View/Open |
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