There is an operator, called the Hamiltonian, that plays a special role in quantum theory because the dynamics of a system can be conveniently formulated by tracking its evolution. The Hamiltonian – written \(H\), or \(\hat{H}\) – stands for the total energy of the system. Its eigenvalues are the possible results that might be obtained in measurements of total energy. It is given by summing over the kinetic and potential energies of the system’s components.