Local Quantum Network Based on Background Electromagnetic Vacuum Fluctuations

Electromagnetic vacuum fluctuations, as an unavoidable environment, plays important role in quantum information tasks. Though it plays a passive role in quantum teleportation, as the fluctuations make the initial entanglement decrease with time, it can also generate the past-future correlation between the sending and receiving nodes. In the present work, by utilizing past-future correlation generated by the background vacuum-fluctuated electromagnetic field, the state factor is transferred between two polarizable, controlled and initially separable two-level atoms located at different positions and evolving with the fluctuating field at different times. Results show that to transmit state factor with sufficient precision, there may exist specific local regions within both the ranges of time difference and the spatial separation between the two atoms. The sizes of the time region and spatial region are shown to be in relation with the width of mode ranges as well as the coupled strength, and it can also be controlled by further restricting the directions of the field modes to a certain range.