String Theory seminar - Jorge Russo Seminar

 

In quantum field theory, charged particles with spin ≥1 may become tachyonic in the presence of magnetic fluxes above some critical field, signaling an instability of the vacuum. The phenomenon is generic, in particular, similar instabilities are known to exist in open and closed string theory, where a spinning string state can become tachyonic above a critical field. In compactifications involving RR fluxes, the quantum states which could become tachyonic by the same Nielsen-Olesen mechanism are Dp-branes. By constructing an appropriate background with RR magnetic flux, and computing its energy spectrum, we argue that there are high spin Dp quantum states which become very light at critical fields.