  The development of efficient artificial nanodevices poses challenges which
are of fundamental and technological nature. Recent progress has been made in
the context of finite-time thermodynamics. A central question in finite-time
thermodynamics is to identify the optimal procedure to extract the greatest
amount of work from a system operating under well-defined constraints. For
externally controlled small systems, the optimal driving protocol maximizes the
mean work spend in a finite-time transition between two given system states.
For simplicity we consider an externally controlled single level system, which
is embedded in a thermal environment and coupled to a particle reservoir. The
optimal protocols are calculated from a master equation approach for different
system-reservoir couplings. For open systems, the system-reservoir couplings
are shown to have a striking influence on the optimal driving setup. We point
out that the optimal protocols have discontinuous jumps at the initial and
final times. Finally, this work provides a first attempt to extend these
calculations to larger system sizes.
