Sine-Gordon parametric resonance

摘要: Abstract We consider the instability of fluctuations in an oscillating scalar field which obeys sine-Gordon equation. present simple closed-form analytic solutions describing parametric resonance model. The structure differs from that obtained with Mathieu equation is usually derived small angle approximation to for fluctuations. results are applied axion cosmology, where oscillations classical field, a self-interaction potential, constitute cold dark matter universe. When misalignment at QCD epoch, θ 0 , small, not significant. However, regions larger miniclusters would form, may be important. As result, disintegrate into finer, denser clumps. also apply theory reheating Natural Inflation scenario. decay inflaton due alone ineffective, but coupling other bosons can lead preheating broad regime. Together fermions, this alter scenario Inflation.