A Quantum Computing View on Unitary Coupled Cluster Theory

Understand

We present a review of the Unitary Coupled Cluster (UCC) ansatz and related ans\"atze which are used to variationally solve the electronic structure problem on quantum computers.

• A brief history of coupled cluster (CC) methods is provided, followed by a broad discussion of the formulation of CC theory.
• This includes touching on the merits and difficulties of the method and several variants, UCC among them, in the classical context, to motivate their applications on quantum computers.
• In the core of the text, the UCC ansatz and its implementation on a quantum computer are discussed at length, in addition to a discussion on several derived and related ans\"atze specific to quantum computing.