  We study the measure of complexity in solid Argon system from the time series
data of kinetic energy of single Argon atoms at different equilibrated
temperatures. To account the inherent multi-scale dependence of the complexity,
the multi-scale entropy of the time series of kinetic energy of individual
Argon atoms are computed at different equilibrated temperatures. The
multi-scale entropy study reveals that the dynamics of an atom becomes more
complex at higher temperatures and the result corroborates well with the
variation of the pair correlation function of the atoms in the solid Argon
crystal. Also, we repeat the multi-scale entropy analysis for program generated
Levy noise time series and for time series data obtained from the outcomes of
exponential decay with noise dx(t) = -x(t) dt + sigma dB(t) (Langevin
equation). Our study establishes that the scale dependence of sample entropy
for time series of kinetic energy of individual atoms in solid Argon system has
similar tendency as that of Levy noise time series and the outcomes of
exponential decay with noise (Langevin equation).
