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 pseudospectral methods, we find that significant single-peak stochastic gravitational-wave backgrounds are generated during preheating for asymptotic linear |φ| and φ2/3 potentials in axion monodromy inflation and cuspy potentials. This may allow us to explore string compactifications through gravitational waves.