Toward Simulation-Based Inference of Inflation with Lattice Simulations

Abstract

Simulating inflation is emerging as a powerful technique for studying inflationary phenomenology beyond the standard paradigm of single-field, slow-roll, and perturbative dynamics. In this talk, I will present recent results from lattice simulations of axion-gauge inflationary models that exhibit a rich phenomenology, including an enhanced small-scale power spectrum, a blue-tilted equilateral-peaked, but ultimately non-separable, bispectrum, and higher-order correlation functions that violate parity. I will also present new results characterizing the CMB power spectrum and bispectrum signatures of these models. The output of our simulations consists of realizations of the primordial curvature field imbued with this nontrivial hierarchy of N-point statistics. Crucially, such realizations cannot be generated with standard techniques for primordial non-Gaussian initial conditions, making our approach essential for comprehensive analysis using field-level and simulation-based inference. Using the output of our inflation simulations as initial conditions for N-body simulations, we effectively simulate the entire history of the universe from inflation to late-time large-scale structure, characterizing the observable predictions of axion-gauge inflation for galaxy surveys. These results establish simulating inflation as an indispensable tool for broadening the space of testable early-universe theories.