Separating Transformations for Controlled Variable Molecular Dynamics

Ben Leimkuhler

We show that Nos\'{e}'s thermostat can be given a mechanical formulation (with Hamiltonian having a Euclidean kinetic energy metric). We also give a mechanical formulation for simultaneous control of temperature and pressure. This approach simplifies the construction of symplectic methods while providing a more intuitive perspective on the nature of the controlled variable molecular dynamics.