Resource-Efficient Hybrid Quantum-Classical Simulation Algorithm

TL;DR

This paper introduces a resource-efficient hybrid quantum-classical simulation algorithm that leverages fault-tolerant quantum computers to efficiently simulate quantum dynamics, overcoming key bottlenecks in quantum property extraction.

Contribution

It proposes a novel hybrid simulator that reduces quantum resource consumption and avoids optimization issues, enhancing large system quantum dynamics simulation.

Findings

Reduces quantum resource requirements for long-time simulations

Avoids barren plateau issues in quantum optimization

Enables efficient simulation of unknown superpositions

Abstract

Digital quantum computers promise exponential speedups in performing quantum time-evolution, providing an opportunity to simulate quantum dynamics of complex systems in physics and chemistry. However, the task of extracting desired quantum properties at intermediate time steps remains a computational bottleneck due to wavefunction collapse and no-fast-forwarding theorem. Despite significant progress towards building a Fault-Tolerant Quantum Computer (FTQC), there is still a need for resource-efficient quantum simulators. Here, we propose a hybrid simulator that enables classical computers to leverage FTQC devices and quantum time propagators to overcome this bottleneck, so as to efficiently simulate the quantum dynamics of large systems initialized in an unknown superposition of a few system eigenstates. It features no optimization subroutines and avoids barren plateau issues, while consuming fewer quantum resources compared to standard methods when many time steps are required.