The $2B Molecule
To Prof Robert Ditchfield, who taught us Quantum Chemistry (Chem 81) in the fall of 1991, and ignited a spark that still burns today! Thank you for being one of my most memorable teachers at Dartmouth!
Published estimates of developing a new medicine span hundreds of millions to several billion US dollars once failed programmes and financing costs are included.1 That bill is not a quantum-chemistry budget; clinical trials, manufacturing, regulation, and failure account for much of it. Early decisions nevertheless depend on questions about molecular energies, bonding, and reaction pathways.
To expose the quantum workflow, Unit 3 uses the smallest chemistry example that carries the full loop: a reduced two-qubit Hamiltonian for \(\mathrm{H}_2\) at one bond length.