Long-Range Entangled Quantum Noise Radar Over Order of Kilometer
In this paper, an explicit expression for the maximum detection range of an entangled quantum two-mode squeezed (QTMS) radar, in which a two-mode squeezed vacuum state of microwave electromagnetic fields is used, have been derived by considering both the quantum properties of the entangled microwave fields and radar parameters. By comparing this equation with that of traditional radars, we showed that one can though a QTMS radar as a traditional radar with a reduced threshold signal-to-noise ratio. By discussing the current limitations, it has been shown that the critical parameter to have both simultaneous quantum advantage and substantial radar range is increasing the bandwidth of the generated output signal in the quantum entangled source. It has been shown that by considering the current feasible system parameters, it is possible to implement a QTMS radar with maximum detection range up to the order of $2\mathrm{km}$, which is suitable for recognizing small unmanned aerial vehicles in urban distances. Moreover, based on the false alarm rate, we introduce two classes of early alarm and track QTMS radars. The present approach can be generalized to other quantum radars with different types of quantum sources like electro-opto-mechanical sources, and also may shed new light on investigating the quantum radar system toward practical applications. Finally, we have discussed the potential outlooks to improve and develop the quantum entangled radar systems to be practical from the engineering point of view.