Quantum Assisted Simulator

TL;DR

This paper introduces a new hybrid quantum-classical algorithm for simulating quantum system dynamics that avoids feedback loops and complex measurements, making it more practical for current quantum computers.

Contribution

It presents a novel variational quantum simulation method that bypasses the barren plateau problem and does not need classical-quantum feedback or complex measurements.

Findings

Compatible with current experimental capabilities

Eliminates the need for classical-quantum feedback loops

Avoids complex measurement procedures

Abstract

Quantum simulation can help us study poorly understood topics such as high-temperature superconductivity and drug design. However, existing quantum simulation algorithms for current quantum computers often have drawbacks that impede their application. Here, we provide a novel hybrid quantum-classical algorithm for simulating the dynamics of quantum systems. Our approach takes the Ansatz wavefunction as a linear combination of quantum states. The quantum states are fixed, and the combination parameters are variationally adjusted. Unlike existing variational quantum simulation algorithms, our algorithm does not require any classical-quantum feedback loop and by construction bypasses the barren plateau problem. Moreover, our algorithm does not require any complicated measurements such as the Hadamard test. The entire framework is compatible with existing experimental capabilities and thus can be implemented immediately.