where Δ U = U (State y) − U (State x) is the difference in potential energy, β = 1/ kT (T is the temperature in kelvins, while k is the Boltzmann constant), and M ( x ) ≡ ≡ min ( e − − x , 1 ) is the Metropolis function. The resulting states are then sampled according to the Boltzmann distribution of the super state at temperature T. Alternatively, if the system is dynamically simulated in the canonical ensemble (also called the NVT ensemble), the resulting states along the simulated trajectory are likewise distributed. Averaging along the trajectory (in either formulation) is denoted by angle brackets ⟨ ⋯ ⋯ ⟩ .