  We examine the performance of a quantum phase gate implemented with cold
neutral atoms in microtraps, when anharmonic traps are employed and the effects
of finite temperature are also taken into account. Both the anharmonicity and
the temperature are found to pose limitations to the performance of the quantum
gate. We present a quantitative analysis of the problem and show that the phase
gate has a high quality performance for the experimental values that are
presently or in the near future achievable in the laboratory.
