The Art of Lattice and Gravity Waves from Preheating

TL;DR

This paper introduces HLATTICE, a new high-accuracy lattice simulation code for studying nonlinear preheating dynamics after inflation, including metric perturbations and gravitational waves.

Contribution

The paper presents HLATTICE, a novel lattice code with higher accuracy, comprehensive metric perturbation inclusion, and improved scalar/vector component removal, advancing preheating simulations.

Findings

Enhanced accuracy in gravitational wave calculations from preheating.

Inclusion of scalar, vector, and tensor metric perturbations.

Effective removal of scalar and vector components in simulations.

Abstract

The nonlinear dynamics of preheating after early-Universe inflation is often studied with lattice simulations. In this work I present a new lattice code HLATTICE. It differs from previous public available codes in the following three aspects: (i) A much higher accuracy is achieved with a modified sixth-order symplectic integrator; (ii) scalar, vector, and tensor metric perturbations in synchronous gauge and their feedback to the dynamics of scalar fields are all included; (iii) the code uses a projector that completely removes the scalar and vector components defined by the discrete spatial derivatives. Such a generic code can have wide range of applications. As an example, gravity waves from preheating after inflation are calculated with a better accuracy.