Efficient Low-Depth UCC algorithm for Quantum Computing*

The unitary coupled cluster (UCC) ansatz is one of the most promising ansatzes for quantum computation of electronic structure calculations. However, for large systems and for many orbitals, the number of UCC factors quickly leads to very deep quantum circuits. We address this by using Taylor expansions for UCC factors that have small angles, while we treat the large amplitude factors exactly. This greatly reduces the circuit depth at the cost of more measurements. This approach is further optimized by employing the hidden SU(2) group symmetry of the UCC factors of arbitrary rank. In this talk, we review progress made in the implementation of this algorithm, and look to future implementations.