Stochastic Gravitational-Wave Background from Axion-Monodromy Oscillons
  in String Theory During Preheating
  Axion monodromy is a generic phenomenon in string compactifications. We
investigate the production of gravitational-wave background from axion
monodromy inflation during preheating. By performing lattice simulations using
pseudo-spectral methods, we find that significant single-peak stochastic
gravitational-wave backgrounds are generated during preheating for asymptotic
linear $|\phi|$ and $\phi^{2/3}$ potentials in axion monodromy inflation and
cuspy potentials. This may allow us to explore string compactifications through
gravitational waves.
