  Inspired by string theory ideas, we probe quantum entanglement from the
gravitational potential energy. Concretely, we reconsider the study of quantum
corrections to the Newtonian potential energy by treating a massive
two-particle system $m_{1}$ and $m_{2}$ with size dimensions $r_{1}$ ad $%
r_{2}$ where the two particles separated by a distance $d$ are under only their
mutual classical gravitational interaction $V_{r}\left( r_{1}\text{, }%
r_{2}\right) $. Exploring such a size-dependent gravitational behavior and
taking the limit $r_{1}$, $r_{2}\ll d$, we investigate the associated quantum
biparticle state and express its evolution after an interaction time $\tau $.
Among others, we show that the two masses cannot be separable due to the
induced gravitational entanglement in terms of the accumulated quantum phase
$\delta \phi =\delta V_{g}\tau /\hbar $. By analogy with the classical gravity,
we derive the expression of the resulting extremely weak entanglement force
from the corresponding gravitational entanglement energy. Then, we provide
certain entanglement diagnostics.
