  Low-energy nuclear fusion reactions have been described using a dynamical
coupled-channels density matrix method, based on the theory of open quantum
systems. For the first time, this has been combined with an energy projection
method, permitting the calculation of energy resolved fusion probabilities. The
results are benchmarked against calculations using stationary Schr\"odinger
dynamics and show excellent agreement. Calculations of entropy, energy
dissipation and coherence were conducted, demonstrating the capability of this
method. It is evident that the presence of quantum decoherence does not affect
fusion probability. This framework provides a basis for quantum thermodynamic
studies using thermal environments.
