Ab initio calculation of the Hoyle state

TL;DR

This paper presents the first ab initio lattice simulation of the carbon-12 nucleus, successfully reproducing the Hoyle state and providing insights into its structure and the fine-tuning of stellar carbon production.

Contribution

It introduces a novel first-principles computational approach to accurately model the Hoyle state in carbon-12, a key step in nuclear physics and astrophysics.

Findings

Successfully identified the Hoyle state with correct energy

Provided structural insights into the Hoyle state

Demonstrated the effectiveness of lattice effective field theory

Abstract

The Hoyle state plays a crucial role in the hydrogen burning of stars heavier than our sun and in the production of carbon and other elements necessary for life. This excited state of the carbon-12 nucleus was postulated by Hoyle [1] as a necessary ingredient for the fusion of three alpha particles to produce carbon at stellar temperatures. Although the Hoyle state was seen experimentally more than a half century ago [2,3], nuclear theorists have not yet uncovered the nature of this state from first principles. In this letter we report the first ab initio calculation of the low-lying states of carbon-12 using supercomputer lattice simulations and a theoretical framework known as effective field theory. In addition to the ground state and excited spin-2 state, we find a resonance at -85(3) MeV with all of the properties of the Hoyle state and in agreement with the experimentally observed energy. These lattice simulations provide insight into the structure of this unique state and new clues as to the amount of fine-tuning needed in nature for the production of carbon in stars.