Accelerating Lattice Quantum Field Theory Calculations via Interpolator Optimization Using Noisy Intermediate-Scale Quantum Computing.

A. Avkhadiev,R. D. Young,P. E. Shanahan

doi:10.1103/physrevlett.124.080501

A. Avkhadiev, R. D. Young + Show 1 more

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https://doi.org/10.1103/physrevlett.124.080501

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Abstract

The only known way to study quantum field theories in nonperturbative regimes is using numerical calculations regulated on discrete space-time lattices. Such computations, however, are often faced with exponential signal-to-noise challenges that render key physics studies untenable even with next generation classical computing. Here, a method is presented by which the output of small-scale quantum computations on noisy intermediate-scale quantum era hardware can be used to accelerate larger-scale classical field theory calculations through the construction of optimized interpolating operators. The method is implemented and studied in the context of the 1+1-dimensional Schwinger model, a simple field theory which shares key features with the standard model of nuclear and particle physics.

Highlights

Numerical approaches to quantum field theory are the only known way to make predictions for a wide range of physical quantities from the standard model of particle physics, our best current theory of nature at the smallest scales
Hybrid methods coupling classical and quantum computing offer a natural pathway to exploit quantum computation despite the small number of qubits, sparse qubit connectivity, lack of error correction, and noisy quantum gates that are hallmarks of current and near-term quantum computing in the noisy intermediate-scale quantum (NISQ) era [7]
In order to reliably extract the desired piece, the contributions from all of these unwanted higher-energy states must be suppressed. This is achieved via an evolution in the Euclidean time of the calculation; the unwanted states are exponentially suppressed by the energy gap to the ground state at large times, but at the cost of an exponential growth in the statistical noise of the Monte Carlo sampling used in the computation

Summary

Introduction

Numerical approaches to quantum field theory are the only known way to make predictions for a wide range of physical quantities from the standard model of particle physics, our best current theory of nature at the smallest scales. A significant contribution to the computational cost of LQFT studies could be eliminated by the construction of optimized interpolating operators, corresponding in broad terms to approximations to the quantum wave function of the desired state.

Results

Conclusion