Fault-Tolerant Quantum Algorithm for Symmetry-Adapted Perturbation Theory

Traditional methods can estimate total interaction energies, but breaking these down into components such as electrostatics, exchange, induction, and dispersion provides valuable insight for rational drug design. Symmetry-adapted perturbation theory (SAPT) is a well-established method for this type of energy decomposition, though it can be computationally demanding for strongly correlated molecules.

Our recent paper introduces the first quantum algorithm for calculating SAPT observables on a fault-tolerant quantum computer. By combining tensor factorizations and block-encodings, the method achieves Heisenberg-limited precision and provides concrete resource estimates for benchmark molecules.