VIBRATIONAL DECOHERENCE IN ION-TRAP QUANTUM COMPUTERS

The ion trap quantum computer proposed by CIRAC and ZOLLER [Phys Rev. Lett. 74, 4091 (1995)] is analyzed for decoherence due to vibrations o f the ions. An adiabatic approximation exploiting the vast difference between the frequencies of the optical intraionic transition and the v ibrational modes is used to find the decoherence time at any temperatu re T. The scaling of this decoherence time with the number of ions is discussed, and compared with that due to spontaneous emission.