On Quantum Simulation Of Cosmic Inflation

TL;DR

This paper extends quantum simulation algorithms to 3+1 dimensional inflationary spacetime, enabling predictions of cosmic non-Gaussianities and benchmarking quantum devices for cosmological models.

Contribution

It generalizes the Jordan-Lee-Preskill algorithm for inflationary spacetime, including state preparation, evolution, and measurement, with detailed discussions on lattice regularization and encoding methods.

Findings

Provides a framework for simulating cosmic inflation on quantum devices

Offers methods for predicting non-Gaussianities in the early universe

Serves as benchmark problems for quantum simulation of cosmological phenomena

Abstract

In this paper, we generalize Jordan-Lee-Preskill, an algorithm for simulating flat-space quantum field theories, to 3+1 dimensional inflationary spacetime. The generalized algorithm contains the encoding treatment, the initial state preparation, the inflation process, and the quantum measurement of cosmological observables at late time. The algorithm is helpful for obtaining predictions of cosmic non-Gaussianities, serving as useful benchmark problems for quantum devices, and checking assumptions made about interacting vacuum in the inflationary perturbation theory. Components of our work also include a detailed discussion about the lattice regularization of the cosmic perturbation theory, a detailed discussion about the in-in formalism, a discussion about encoding using the HKLL-type formula that might apply for both dS and AdS spacetimes, a discussion about bounding curvature perturbations, a description of the three-party Trotter simulation algorithm for time-dependent Hamiltonians, a ground state projection algorithm for simulating gapless theories, a discussion about the quantum-extended Church-Turing Thesis, and a discussion about simulating cosmic reheating in quantum devices.