QUANTUM COMPUTATION WITH PHASE DRIFT ERRORS

We numerically simulate the evolution of an ion trap quantum computer made out of 18 ions subject to a sequence of nearly 15 000 laser pulse s in order to find the prime factors of N=15. We analyze the effect of random and systematic phase drift errors arising from inaccuracies in the laser pulses which induce over (under) rotation of the quantum st ate. Simple analytic estimates of the tolerance for the quality of dri ving pulses are presented. We examine the use of watchdog stabilizatio n to partially correct phase drift errors concluding that, in the regi me investigated, it is rather inefficient.