Theory of coherent optical control of exciton spin dynamics in a semiconductor dot

We use the spin-polarized excitons in a single quantum dot to design optica l controls for basic operations in quantum computing. We examine the ultraf ast nonlinear optical processes required and use the coherent nonlinear opt ical responses to deduce if such processes are physically reasonable. The i mportance and construction of an entangled state of polarized exciton state s in a single quantum dot is explained. We put our proposal in perspective with respect to a number of theoretical suggestions of utilizing the semico nductor quantum dots. (C) 2001 Elsevier Science B.V. All rights reserved.