Digital quantum simulation of cosmological particle creation with IBM quantum computers

TL;DR

This paper demonstrates the digital quantum simulation of cosmological particle creation using IBM quantum computers, modeling a scalar field in an expanding universe and analyzing particle production with error mitigation techniques.

Contribution

It introduces a quantum circuit approach to simulate particle creation in an expanding spacetime on real quantum hardware, bridging quantum computing and cosmology.

Findings

Successful simulation of particle creation on IBM quantum hardware

Error mitigation techniques improve simulation accuracy

Quantum circuits can model cosmological phenomena

Abstract

We use digital quantum computing to simulate the creation of particles in a dynamic spacetime. We consider a system consisting of a minimally coupled massive quantum scalar field in a spacetime undergoing homogeneous and isotropic expansion, transitioning from one stationary state to another through a brief inflationary period. We simulate two vibration modes, positive and negative for a given field momentum, by devising a quantum circuit that implements the time evolution. With this circuit, we study the number of particles created after the universe expands at a given rate, both by simulating the circuit and by actual experimental implementation on IBM quantum computers, consisting of hundreds of quantum gates. We find that state-of-the-art error mitigation techniques are useful to improve the estimation of the number of particles and the fidelity of the state.