  We show that a single photon pulse (SPP) incident on two interacting
two-level atoms induces a transient entanglement force between them. After
absorption of a multi-mode Fock state pulse, the time-dependent atomic
interaction mediated by the vacuum fluctuations changes from the van der Waals
interaction to the resonant dipole-dipole interaction (RDDI). We explicitly
show that the RDDI force induced by the SPP fundamentally arises from the
two-body transient entanglement between the atoms. This SPP induced
entanglement force can be continuously tuned from being repulsive to attractive
by varying the polarization of the pulse. We further demonstrate that the
entanglement force can be enhanced by more than three orders of magnitude if
the atomic interactions are mediated by graphene plasmons. These results
demonstrate the potential of shaped SPPs as a powerful tool to manipulate this
entanglement force and also provides a new approach to witness transient
atom-atom entanglement.
