Efficient Symmetry-Preserving State Preparation Circuits for the Variational Quantum Eigensolver Algorithm

Understand

The variational quantum eigensolver is one of the most promising approaches for performing chemistry simulations using noisy intermediate-scale quantum (NISQ) processors.

• The efficiency of this algorithm depends crucially on the ability to prepare multi-qubit trial states on the quantum processor that either include, or at least closely approximate, the actual energy eigenstates of the problem being simulated while avoiding states that have little overlap with them.
• Symmetries play a central role in determining the best trial states.
• Here, we present efficient state preparation circuits that respect particle number, total spin, spin projection, and time-reversal symmetries.