D-instantons and String Field Theory
Citation
Agmon, Nathan Benjamin. 2023. D-instantons and String Field Theory. Doctoral dissertation, Harvard University Graduate School of Arts and Sciences.Abstract
In this thesis, we study D-instanton contributions to supergraviton scattering amplitudes in ten-dimensional type IIB superstring theory beyond the leading non-perturbative order. Our computation is based on the Neveu-Schwarz-Ramond (NSR) formalism with picture changing operators and vertical integration. In the first chapter, we determine the single D-instanton contribution to maximal R-symmetry violating (MRV) amplitudes with arbitrary momenta at the first subleading order in string coupling, as well as the effects of a D-/anti-D-instanton pair at leading nontrivial order in the momentum expansion. These results confirm a number of predictions of S-duality, and unveil some previously unknown pieces of type IIB string amplitudes.The naive on-shell prescription for D-instanton mediated amplitudes, based on integration over the moduli space of worldsheet geometries as well as that of D-instanton boundary conditions, suffers from potential open string divergences and regularization ambiguities. In the second chapter, we employ the framework of open+closed superstring field theory (SFT) to address such issues. From this, we are able to unambiguously compute a part of the momentum-independent constant that appears at first subleading order in the string coupling, which serves as a highly nontrivial consistency check on spacetime supersymmetry and soft relations.
Terms of Use
This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAACitable link to this page
https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37375763
Collections
- FAS Theses and Dissertations [6138]
Contact administrator regarding this item (to report mistakes or request changes)