Alexander Westphal (physicist)
Alexander Westphal (* 1977 in Rinteln ) is a German theoretical physicist who deals with string theory , cosmology and supersymmetry .
Westphal went to high school in Rinteln, studied physics at the Ruprecht-Karls-Universität Heidelberg from 1997 with a diploma in 2002 (for the diploma thesis he received the Otto Haxel Prize) and received his doctorate in 2005 from the University of Hamburg and DESY . As a post-doctoral student he was at SISSA in Trieste and at the INFN and from 2007 to 2010 at Stanford University (SLAC), among others with Eva Silverstein and Andrei Linde (who also deal with inflation models and string theory). From 2007 to 2009 he was a Feodor Lynen scholarship holder and from 2010 to 2014 a Helmholtz Fellow. From 2014 he was part of Desy's theory group and from 2015 group leader with an ERC Consolidator Grant for five years.
He deals with inflation models in the context of string theory and the resulting signs in observation data (primordial gravitational wave signals in the polarization of the cosmic background radiation CMB). That would enable observational tests of string theory and the vacuum state realized in the universe.
Fine-tuned inflationary potential parameters are sensitive to quantum corrections and the hope is that string theory can control them. According to Westphal and Silverstein (2008), this can be done through the mechanism of axion monodromy. String theory (including branes) has many scalar axion- like fields (they arise from the higher-dimensional gauge fields through integration over the compactified extra dimensions). The inflation potential is built up from such scalar fields. However, the potential has residual structures from the moduli of string theory (symmetries in the extra dimensions), for example discrete shift symmetries that protect the inflation potential against quantum corrections. In the case of axion monodromy, they are only approximately periodic, but the protective function remains. The mechanism also explains why the expected traces in the CMB are larger than the Planck scale (trans-Planck size).
In 2015 he received the J. Hans D. Jensen Prize and was then visiting professor in Heidelberg.
Fonts (selection)
- with E. Silverstein: Monodromy in the CMB: Gravity Waves and String Inflation, Phys. Rev. D, Volume 78, 2008, p. 106003
- with Liam McAllister, Eva Silverstein: Gravity Waves and Linear Inflation from Axion Monodromy, Phys. Rev. D, Volume 82, 2010, p. 046003, Arxiv 2008
Web links
Individual evidence
| personal data | |
|---|---|
| SURNAME | Westphal, Alexander |
| BRIEF DESCRIPTION | German physicist |
| DATE OF BIRTH | 1977 |
| PLACE OF BIRTH | Rinteln |