In quantum mechanics, quantum chemistry, and condensed matter physics courses, it seems like finding the ground state energy of a Hamiltonian is incredibly important. I can understand why having the ground state wave function (or behaviors of the wave function) could help, but I’m struggling to understand how the ground state energy helps us.
In Quantum Computing pitches by huge companies, I always hear something along the lines of “Quantum Chemistry simulations will allow for breakthroughs in the pharmaceutical industries,” but the quantum simulation algorithm in quantum computing they refer to is the Variational Quantum Eigensolver, which returns an estimate for the ground state energy. How does knowing this energy tell us anything about the material? I’m struggling to bridge this gap.