Phase breaking and energy relaxation in open quantum-dot arrays

We study both the phase-breaking and the energy-relaxation times as a funct ion of both temperature and bias current in arrays of coupled, open quantum dots. These times show a saturation at low temperature, and a decay at hig her temperatures. Importantly, the variations of sample resistance as a fun ction of temperature and current cannot be used to infer the electron tempe rature at a given bias current, which suggests that the energy relaxation p rocess is likely to be phonon based.