European patent number EP1750145 describes "radar systems and methods using entangled quantum particles". It says such a device could "visualise useful target details through background and/or camouflaging clutter, through plasma shrouds around hypersonic air vehicles, through the layers of concealment hiding underground facilities, [and find] IEDs [improvised explosive devices], mines and other threats - all while operating from an airborne platform". It could also be mounted on a satellite.
No! But wait, it gets better!
The Lockheed Martin patent envisages a different use for entanglement. Current radar systems become less useful as range increases, because the frequencies needed to transmit over long distances are less sensitive. According to the patent this problem can be removed by entangling light at different frequencies and then sending them out together as a bundle.
It says: "Entangled radar waves can combine one or more particles with a relatively high frequency for resolution, with one or more particles at a lower frequency for more effective propagation." The radar beam could then "propagate through different types of mediums and resolve different types of target".
Analysing the return signal would reveal the "location, speed, direction of travel, distance to target, target image, target size, target area, target volume, target dimensions, target cross-section, target surface roughness and target material composition", the patent claims.
Correct me if I'm wrong, but there are two problems with this:
1. We have not had any reliable applications yet of quantum entanglement, especially in sending and receiving information. I know the Zeilinger group has sent signals of kilometers, but this is still in a highly experimental stage. Certainly no experiment of any kind has been verified to do what this patent is claiming, even at the simplest stage.
2. Correct me if I'm wrong, but I don't believe there has been any kind of detection of entanglement of photons in the frequency of a radar. Are they detecting entanglement of the whole "bundle"?
Considering all the possible loss of coherence along the way, I'd say that they should have demonstrated, at the very least, how this is possible at that frequency, especially making the detection.
... and these people are US defense contractors? Yowzah!