  The dynamics of the quantum Fisher information of the parameters of the
initial atomic state and atomic transition frequency is studied, in the
framework of open quantum systems, for a static polarizable two-level atom
coupled in the multipolar scheme to a bath of fluctuating vacuum
electromagnetic fields without and with the presence of a reflecting boundary.
Our results show that in the case without a boundary, the electromagnetic
vacuum fluctuations always cause the quantum Fisher information of the initial
parameters and thus the precision limit of parameter estimation to decrease.
Remarkably, however, with the presence of a boundary, the quantum Fisher
information becomes position and atomic polarization dependent, and as a
result, it may be enhanced as compared to that in the case without a boundary
and may even be shielded from the influence of the vacuum fluctuations in
certain circumstances as if it were a closed system.
