Consider a system characterized by an observable A, with A * representing the experimental measurement of A. Under an existing force field characterized with parameters θ 0 , the system's canonical ensemble Z 0 follows a Boltzmann distribution p(x; θ 0 ) ∝ exp(-βU (x; θ 0 )), where x is the system's configuration and U (x; θ 0 ) its potential energy given the force field parameters θ 0 . Here, β = 1/k B T , with k B as the Boltzmann constant and T the temperature.