# Pathfinding quantum simulations of neutrinoless double-β decay

## TL;DR

This paper uses quantum computers to simulate a rare nuclear decay process, which could help in understanding fundamental physics.

## Contribution

The paper presents the first co-designed quantum simulation of neutrinoless double-β decay using trapped-ion quantum computers.

## Key findings

- Lepton-number violation was observed in real time, indicating neutrinoless double-β decay.
- Quantum simulations were optimized using error-mitigation methods and native gate-sets of IonQ’s quantum computers.
- The results suggest future quantum simulations could achieve yocto-second resolution of nuclear processes.

## Abstract

We present results from co-designed quantum simulations of the neutrinoless double-β decay of a simple nucleus in 1+1D quantum chromodynamics using IonQ’s Forte-generation trapped-ion quantum computers. Electrons, neutrinos, and up and down quarks are distributed across two lattice sites and mapped to 32 qubits, with an additional 4 qubits used for flag-based error mitigation. A four-fermion interaction is used to implement weak interactions, and lepton-number violation is induced by a neutrino Majorana mass. Quantum circuits that prepare the initial nucleus and time evolve with the Hamiltonian containing the strong and weak interactions are executed on IonQ Forte Enterprise. Enabled by tuned model parameters, lepton-number violation is observed in real time, providing a clear signal of neutrinoless double-β decay. This was made possible by co-designing the simulation to maximally utilize the all-to-all connectivity and native gate-set available on IonQ’s quantum computers. Quantum circuit compilation techniques and co-designed error-mitigation methods, informed from executing benchmarking circuits with up to 2,356 two-qubit gates, enabled observables to be extracted with high precision. We discuss the potential of future quantum simulations to provide yocto-second resolution of the reaction pathways in these, and other, nuclear processes.

In this work, an exotic nuclear decay in one dimension is simulated using IonQ trapped-ion quantum computers. The coherent evolution of many decay channels is classically hard and quantum simulation of these processes may impact future searches for new physics.