On universality of hardware-efficient ansatzes

TL;DR

This paper demonstrates that certain hardware-efficient ansatzes in quantum computing are computationally universal, capable of representing any relevant quantum circuit efficiently, which has implications for their use in near-term quantum applications.

Contribution

The paper proves that some classes of hardware-efficient ansatzes are BQP-complete, establishing their universality in quantum circuit simulation.

Findings

HEA classes are BQP-complete

Any relevant quantum circuit can be efficiently represented as an HEA

Implications for near-term quantum computing applications

Abstract

The hardware-efficient ansatz (HEA) is one of the most important class of parametrized quantum circuits for near-term applications of quantum computing. We show that the problem of simulating some major classes of the HEA is BQP-complete by explicitly demonstrating that any relevant quantum circuit can be efficiently represented as an HEA circuit of those classes.