  We derive the formulas of the squeezed back-to-back correlation (SBBC)
between a boson and antiboson with different in-medium masses in high-energy
heavy-ion collisions. The influence of the in-medium mass difference between a
boson and antiboson on the SBBC is investigated. We calculate the SBBC
functions of $D$-meson pairs for the hydrodynamic sources described by the
VISH2+1 code for Au+Au collisions at $\sqrt{s_{NN}} =200$~GeV. Our results
indicate that the SBBC strengths of $D^+D^-$ and $D^0{\bar D}^0$ are different
if there are charge-dependent in-medium interactions.
