Tachyons, Hagedorn transitions and degrees of freedom in superstring theory

by Carlo Angelantonj (Turin University, CERN)

Tuesday 28 Apr 2009, 14:00 → 15:00 Europe/Zurich

TH Theory Conference Room (CERN)

I will present closed type II and orientifold backgrounds where supersymmetry is spontaneously broken by asymmetric geometrical fluxes. We show that these can be used to describe thermal ensembles with chemical potentials associated to “gravito-magnetic” fluxes. The thermal free energy is computed at the one-loop string level, and it is shown to posses low temperature - high temperature duality and to be free of the usual Hagedorn-like instabilities for a certain choice of the chemical potentials. In the second part of the talk I will discuss a tachyon-free purely bosonic string theory and comment on its IR and UV properties.