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Math-Physics Joint Seminar

Thursday, May 4, 2017 - 4:30pm

Ron Donagi



University of Pennsylvania


Supersymmetry is expected to be spontaneously broken at one-loop order in certain compactifications of the heterotic string. Justification of this claim in superstring perturbation theory leads to an exploration of the geometry of Deligne-Mumford compactifications of supermoduli space. The novel behavior occurs near the Ramond boundary divisor, which is exotic in several ways. One of these unexpected bahviors is that its normal bundle, already in genus 1, depends essentially on the odd directions: the divisor maps to its reduced space, but the normal bundle is not a pullback from this reduced space. This leads to the spontaneous breaking of supersymmetry at 1 loop.