  While thermodynamics is a useful tool to describe the driving of large
systems close to equilibrium, fluctuations dominate the distribution of heat
and work in small systems and far from equilibrium. We study the heat generated
by driving a small system and change the drive parameters to analyse the
transition from a drive leaving the system close to equilibrium to driving it
far from equilibrium. Our system is a quantum dot in a GaAs/AlGaAs
heterostructure hosting a two-dimensional electron gas. The dot is
tunnel-coupled to one part of the two-dimensional electron gas acting as a heat
and particle reservoir. We use standard rate equations to model the driven
dot-reservoir system and find excellent agreement with the experiment.
Additionally, we quantify the fluctuations by experimentally test the
theoretical concept of the arrow of time, predicting our ability to distinguish
whether a process goes in the forward or backward drive direction.
