  We theoretically investigated the dephasing in an Aharonov-Bohm
interferometer containing a lateral double quantum dot induced by coupling with
a quantum dot charge sensor. We employed the interpolative 2nd-order
perturbation theory to include the charge sensing Coulomb interaction. It is
shown that the visibility of the Aharonov-Bohm oscillation of the linear
conductance decreases monotonically as the sensing Coulomb interaction
increases. In particular, for a weak sensing interaction regime, the visibility
decreases parabolically, and it behaves linearly for a strong sensing
interaction regime.
