Alexander Westphal

Additional information



Alexander Westphal

T. +49 (0)40 8998 2083




My main research interests move along the boundary between inflationary cosmology, string theory and string phenomenology, and higher-dimensional field theory including supergravity, with some forays into quantum cosmology. Cosmological inflation is described by an effective field theory which is sensitive to quantum gravity effects potentially spoiling the slow-roll flatness of the inflaton scalar field potential driving the inflationary process. Reining in this sensitivity to Planck scale suppressed corrections requires an embedding of inflation into candidate theories of quantum gravity like string theory. Such a description of in particular high-scale inflation with a potentially detectable primordial gravitational wave signal in string theory needs to derive the appearance of a protective shift symmetry controlling the dangerous quantum gravity corrections as well as its controlled breaking leading to slow-roll inflation. Recent progress builds on the multi-valuedness of non-perturbative sectors of string theory coupled to the multiple axion fields generically present in string compactifications. This so-called axion monodromy can provide the underlying dynamics of controlled high-scale and “large-field” inflation models in string theory, and even more recently, also of shift-symmetry protected electro-weak hierarchy generation via relaxation.

Academic career

since 2015 ERC consolidator grant holder and ERC group leader
since 2014 DESY theory group staff member (tenured)
2010-2014 DESY theory group staff member and Helmholtz fellow (tenure track)
2007-2010 Postdoc at Stanford University (USA; 2007-09 Humboldt Feodor Lynen fellow)
2005-2007 Research associate at ISAS/SISSA, Trieste (Italy)
2002-2005 Ph.D. in physics, DESY / Hamburg University
1997-2002 Diploma in physics at Heidelberg University

Memberships, awards, honours

2015-2020 ERC consolidator grant "Inflation in String Theory - Connecting Quantum Gravity with Observations"
2015 J. Hans D. Jensen Prize of Heidelberg University and the Klaus Tschira Foundation
2010-2015 Helmholtz fellow of the Helmholtz Association
2007-2009 Feodor Lynen fellowship by the Alexander v. Humboldt Foundation, Germany
2005-2007 Research fellowship, INFN (Italy)
2002 Otto Haxel award "For an Outstanding Diploma Thesis" by the Faculty of Physics and Astronomy of Heidelberg University
1998-2002 Scholarship of the "Evangelisches Studienwerk Haus Villigst e.V."