  In the last ten years, a number of ``Conventional Fluctuation Theorems'' have
been derived for systems with deterministic or stochastic dynamics, in a
transient or in a non-equilibrium stationary state. These theorems gave
explicit expressions for the ratio of the probability to find the system with a
certain value of entropy (or heat) production to that of finding the opposite
value. A similar theorem for the fluctuations of the work done on a system has
recently been demonstrated experimentally for a simple system in a transient
state, consisting of a Brownian particle in water, confined by a moving
harmonic potential. In this paper we show that because of the interaction
between the stochastic motion of the particle in water and its deterministic
motion in the potential, very different new heat theorems are found than in the
conventional case. One of the consequences of these new heat Fluctuation
Theorems is that the ratio of the probability for the Brownian particle to
absorb heat from rather than supply heat to the water is much larger than in
the Conventional Fluctuation Theorem. This could be of relevance for
micro/nano-technology.
