Universal Quantum Circuits

TL;DR

This paper introduces efficient universal quantum circuits that can simulate a wide range of quantum circuits with minimal depth increase and near-optimal size, advancing quantum computational simulation capabilities.

Contribution

The authors construct depth-universal and almost-size-universal quantum circuits, providing near-optimal solutions for general-purpose quantum circuit simulation.

Findings

Depth-universal circuits match the depth of simulated circuits.

Size-universal circuits have a logarithmic size blow-up.

Construction is proven nearly optimal.

Abstract

We define and construct efficient depth-universal and almost-size-universal quantum circuits. Such circuits can be viewed as general-purpose simulators for central classes of quantum circuits and can be used to capture the computational power of the circuit class being simulated. For depth we construct universal circuits whose depth is the same order as the circuits being simulated. For size, there is a log factor blow-up in the universal circuits constructed here. We prove that this construction is nearly optimal.