  We present a detailed analysis and design of a neutral atom quantum logic
device based on atoms in optical traps interacting via dipole-dipole coupling
of Rydberg states. The dominant physical mechanisms leading to decoherence and
loss of fidelity are enumerated. Our results support the feasibility of
performing single and two-qubit gates at MHz rates with decoherence probability
and fidelity errors at the level of $10^{-3}$ for each operation. Current
limitations and possible approaches to further improvement of the device are
discussed.
