Lattice Simulation of Multi-Stream Inflation

TL;DR

This paper uses lattice simulations to explore multi-stream inflation, confirming its physical picture and revealing new insights into parameter effects, field behaviors, and the role of gradient energy.

Contribution

First lattice simulation of multi-stream inflation, providing new understanding of parameter space, field dynamics, and the influence of gradient energy.

Findings

Gradient energy significantly impacts multi-stream inflation.

Bifurcation probability follows an error function relation with shift distance.

Bubbles are more spherical at lower bifurcation probabilities.

Abstract

We present the first lattice simulation to investigate the nature of multi-stream inflation. The simulation confirms the physical picture of multi-stream inflation, and with new findings in parameter space and field behaviors. Our simulation shows that gradient energy plays a significant role in multi-stream inflation. For a double field potential with a shifted Gaussian barrier, bifurcation probability is controlled by the shift distance with an error function relation. The bubbles created by bifurcation tend to be more spherical as bifurcation probability decreases. Also, the bifurcation is more likely to introduce oscillations of field values inside the bubbles than outside.