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  • Open Daily: 10am - 10pm
    Alley-side Pickup: 10am - 7pm

    3038 Hennepin Ave Minneapolis, MN
    612-822-4611

Open Daily: 10am - 10pm | Alley-side Pickup: 10am - 7pm
3038 Hennepin Ave Minneapolis, MN
612-822-4611
Using Observation to Constrain Early Universe Cosmology.

Using Observation to Constrain Early Universe Cosmology.

Giblin, John T. Jr.

Paperback

Biology

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ISBN10: 1243648821
ISBN13: 9781243648822
Publisher: Proquest Umi Dissertation Pub
Pages: 118
Weight: 0.50
Height: 0.25 Width: 7.44 Depth: 9.69
Language: English
The goal of the contemporary cosmologist must be to search for models of the early universe that satisfy current observational tests and to seek new ways to discriminate between these models. At the base of this endeavor is understanding how gravity and quantum field theory can lead to natural models of the early universe and specifically how these models might emerge from various extensions of the Standard Model. This investigation presents new ways by which observations---of both electromagnetic and gravitational radiation---can identify viable cosmological scenarios. The first of these projects extends the canonical treatment of single field slow-roll inflation to models consisting of multiple fields. This is done by defining a system of multiple-field slow-roll parameters. The evolution of these parameters can be described by a set of flow equations whose truncation, to any finite order, can be solved exactly. Further, I show how these parameters are related to cosmological parameters, namely the scalar spectral index, ns, and the tensor to scalar ratio, tau. The second of these projects searches for observational signatures laid down at the end of inflation. As the universe reheats, coherent oscillations of the inflaton field may excite momentum modes of fields to which it is coupled. This process is known as preheating and is an efficient mechanism by which inflationary energy can be converted into matter fields. During this process, large gradient energies should produce gravitational radiation. I develop an algorithm by which this radiation can be calculated and implement its calculation numerically. I show the robustness of this method, and calculate the gravitational wave power spectrum for a number of interesting and useful cases.

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