Saturation of phase breaking in an open ballistic quantum dot

A variation in the saturated phase-breaking time in a ballistic quantum dot is found to occur as the size is varied. This variation differs from that observed earlier, in which a transition from quasi-two-dimensional to zero- dimensional behavior was thought to occur. Instead, these results suggest t hat the saturated phase-breaking rate is governed by a change in the total number of electrons within the dot. At higher temperatures, the phase break ing is governed by coupling to the quantum wire leads, and tau(phi) may sho w the T-2/3 variation expected for a one-dimensional wire due to the electr on-electron interaction. [S0031-9007(99)09335-7].