Efficient quantum computation of molecular forces and other energy gradients

Understand

While most work on the quantum simulation of chemistry has focused on computing energy surfaces, a similarly important application requiring subtly different algorithms is the computation of energy derivatives.

• Almost all molecular properties can be expressed an energy derivative, including molecular forces, which are essential for applications such as molecular dynamics simulations.
• Here, we introduce new quantum algorithms for computing molecular energy derivatives with significantly lower complexity than prior methods.
• Under cost models appropriate for noisy-intermediate scale quantum devices we demonstrate how low rank factorizations and other tomography schemes can be optimized for energy derivative calculations.