Phase relaxation of one-particle states in closed quantum dots

We develop an analytical approach to analyze the effect of dephasing of one-particle states on the magnetoconductance of closed quantum dots. This approach allows us to extract dephasing rates from experimental measurements of the magnetoconductance. The dephasing rates calculated depend on the mean level spacing and are much longer than in open quantum dots. The limited experimental data available are consistent with the theoretical prediction of diverging dephasing times in finite closed systems at sufficiently low temperatures. We also consider fluctuations of the single-electron spectrum, and observe a significant effect on the conductance distribution and magnetoconductance of closed quantum dots at experimentally relevant temperatures.