Enhancing initial state overlap through orbital optimization for faster molecular electronic ground-state energy estimation

Understand

The quantum phase estimation algorithm stands as the primary method for determining the ground state energy of a molecular electronic Hamiltonian on a quantum computer.

• In this context, the ability to initialize a classically tractable state that has a strong overlap with the desired ground state is critical as it directly affects the runtime of the algorithm.
• However, several numerical studies have shown that this overlap decays exponentially with system size.
• In this work, we demonstrate that this decay can be alleviated by optimizing the molecular orbital basis, for an initial state constructed from a single Slater determinant.