Gradients of parameterized quantum gates using the parameter-shift rule and gate decomposition

TL;DR

This paper extends the parameter-shift rule for quantum gradient measurement to a broader class of parameterized gates through decomposition into standard differentiable gates, enabling more versatile quantum circuit optimization.

Contribution

It introduces a method to apply the parameter-shift rule to a wider range of quantum gates via gate decomposition, broadening the scope of gradient-based quantum algorithms.

Findings

Enables gradient measurement for more quantum gates

Facilitates optimization of complex quantum circuits

Does not require additional qubits or controlled operations

Abstract

The parameter-shift rule is an approach to measuring gradients of quantum circuits with respect to their parameters, which does not require ancilla qubits or controlled operations. Here, I discuss applying this approach to a wider range of parameterize quantum gates by decomposing gates into a product of standard gates, each of which is parameter-shift rule differentiable.