Topics in supersymmetry and supergravity : applications to cosmology and scattering amplitudes
Abstract/Contents
- Abstract
- This thesis consists of two parts, which explore related but distinct directions. The first part concerns theories of supersymmetry and supergravity with a spontaneously broken supersymmetry -- specifically, a nonlinearly realized supersymmetry and nilpotent multiplets. From a phenomenological perspective, theories of spontaneously broken supersymmetry are relevant due to the lack of experimental evidence for unbroken supersymmetry at low energies. In recent years, theories with nilpotent multiplets have proven to be useful for constructing cosmological models in a supersymmetric context. To this end, we develop a method of obtaining actions (and multiplets) with a nonlinearly realized supersymmetry from the corresponding linear models by taking the masses of certain particles to infinity -- physically, these infinite-mass particles can be thought of as being integrated out. This generalizes previous work done by Komargodski and Seiberg to (a) all energy scales and (b) to theories with local supersymmetry (supergravity) as well. The supergravities with non-linearly realized supersymmetry have de Sitter vacua with a positive cosmological constant. In the second part, we study scattering amplitudes in two different physical systems -- the N=1 Volkov-Akulov theory, and U(1) anomalous amplitudes in extended supergravities. Anomalies have always been important in theoretical physics, as they give insight into the extent to which classical symmetries control quantum physics. Motivated by work done by Marcus in the 1980s, we study anomalies in extended supergravities from the perspective of anomalous scattering amplitudes. We develop the formalism of linearized superconformal chiral superfields for these theories, and construct candidate one-loop anomalous superinvariants. We find that in N = 5, 6, and 8 supergravities one-loop anomalous amplitudes are absent, which implies a possibility of an improved UV behavior.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Murli, Divyanshu Rohit |
|---|---|
| Degree supervisor | Kallosh, Renata |
| Thesis advisor | Kallosh, Renata |
| Thesis advisor | Kachru, Shamit, 1970- |
| Thesis advisor | Linde, A. D |
| Thesis advisor | Silverstein, Eva, 1970- |
| Degree committee member | Kachru, Shamit, 1970- |
| Degree committee member | Linde, A. D |
| Degree committee member | Silverstein, Eva, 1970- |
| Associated with | Stanford University, Department of Physics. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Divyanshu Rohit Murli. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Divyanshu Rohit Murli
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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