Preheating with higher dimensional interaction

Particle production caused by the oscillation after inflation is important since it explains reheating after inflation. On the particle theory side, we know that effective action may have additional higher dimensional terms (usually called nonrenormalizable terms) suppressed by the cutoff scale. Moreover, interaction between the inflaton and so-called moduli field will be higher dimensional. Therefore, if such higher dimensional interaction is significant for resonant particle production, one cannot avoid the effect in a preheating study. We explicitly calculated the required number of oscillations for the energy transfer. Consequently, cosmological history of an oscillating field and the moduli problem can be reconsidered.

Figure 1

The picture shows our analytical and numerical calculations in Minkowski space for the first particle production ($n_{\chi ,1}$). We took $g=1$, $m_{\varphi }=0.1\mathrm{\Lambda }$, and ${\mathrm{\Phi }}_1=1.0\mathrm{\Lambda }$. [Results are calculated for a flat potential ($m_{\varphi }=0$) with initial condition $\dot{\varphi }=0.1{\mathrm{\Lambda }}^2$.]

Figure 2

The picture shows our numerical calculation in Minkowski space with vanishing impact parameter ($\mu =0$). We took $\varphi (t=0)=1.0\mathrm{\Lambda }$, $\dot{\varphi }(t=0)=0$, $g=1$, and $m_{\varphi }=0.1\mathrm{\Lambda }$. One will see that resonant particle production is efficient even if the quadratic approximation is not valid in the nonadiabatic region.