My understanding as a physics undergrad is that we can write down the 'equations of motion' of molecular systems with Hamiltonians describing the energies and c

My understanding as a physics undergrad is that we can write down the 'equations of motion' of molecular systems with Hamiltonians describing the energies and correlations of the electrons in a system, but they very quickly become intractably difficult to solve. You're trying to solve a very, very big eigenvalue problem. However, with the right kind of quantum computer or quantum simulator, you could construct a system of qubits that is described by the exact same Hamiltonian. That way, the quantum state of your qubits and your original system would behave in exactly the same way. Then, you just let the qubits evolve in time and read out the system's state at the end. Do that a bunch of times and you'll see an average picture of what the original system you're modelling (protein or something) would do. So to recap - we can get around the difficult compute bottleneck caused by the desire to perform high-fidelity physics simulations by creating a system that follows the same rules and which we can probe much more easily.