The dynamics of Morriss and Evans (see end of previous
subsection) was actually a dynamics, with zero fluctuation
of the kinetic energy. A genuine dynamics would constrain
to stay near a desired average but with - hopefully
gaussian distributed - fluctuations around that value.
Such a method was conceived by Hoover (1985).
Extending the Hoover-Nosé idea to keep both the pressure and the
kinetic energy near a desired value , he wrote the equations
of motion as
where and are relaxation times of the pressure and
temperature regulators, respectively.
F. J. Vesely / University of Vienna