Quantum Chemistry and Computing for the Curious

Chapter 5: Variational Quantum Eigensolver (VQE) Algorithm

“Not only is the Universe stranger than we think, it is stranger than we can think.”

– Werner Heisenberg

Figure 5.1 – Steepest descent line on a potential energy surface (PES) [authors]

We introduced the history behind the use of the variational method in Section 1.1, Understanding the history of quantum chemistry and mechanics. It is a mathematical construct that can be used computationally. Within the context of quantum chemistry, the variational method is used to determine the lowest energy associated with an eigenvalue, either the ground state or excited states.

The Variational ...