  We consider the problem of quasiparticle poisoning in a nanowire-based
realization of a Majorana qubit, where a spin-orbit-coupled semiconducting wire
is placed on top of a (bulk) superconductor. By making use of recent
experimental data exhibiting evidence of a low-temperature residual
non-equilibrium quasiparticle population in superconductors, we show by means
of analytical and numerical calculations that the dephasing time due to the
tunneling of quasiparticles into the nanowire may be problematically short to
allow for qubit manipulation.
