An Expressive Ansatz for Low-Depth Quantum Approximate Optimisation

Understand

The quantum approximate optimisation algorithm (QAOA) is a hybrid quantum-classical algorithm used to approximately solve combinatorial optimisation problems.

• It involves multiple iterations of a parameterised ansatz comprising a problem and mixer Hamiltonian, with the parameters being classically optimised.
• While QAOA can be implemented on NISQ devices, physical limitations can limit circuit depth and decrease performance.
• To address these limitations, this work introduces the eXpressive QAOA (XQAOA), an overparameterised variant of QAOA that assigns more classical parameters to the ansatz to improve its performance at low depths.