  In contrast to the general thought that the collisions are intrinsically
dephasing in nature and detrimental to quantum entanglement at room or higher
temperatures, here, we show that in the conventional ladder-type three-level
electromagnetically induced transparency (EIT) configuration, when the probe
field intensity is not very weak as compared to the pump field, the
entanglement between the bright pump and probe fields can be remarkably
enhanced with the increase of the collisional decay rates in a moderate range
in an inhomogeneously-broadened atomic system. The strengthened entanglement
results from the enhancement of constructive interference and suppression of
destructive interference between one-photon and multi-photon transition
pathways. Our results clearly indicate that the collisions offer a promising
alternative to enhance entanglement at room or higher temperatures despite of
the dephasing nature, which provides great convenience for experimental
implementation, and opens new prospects and applications in realistic quantum
computation and quantum information processing.
