Suppose you could watch something — or someone — by observing its doppelganger. Not the thing in itself, but its shadow. Ridiculous? Maybe not. According to the Guardian Lockheed Martin filed a patent application for a quantum radar system which operates on precisely that principle. The Guardian writes:
In theory entangled particles could be used to reveal details of objects they have never interacted with. If one particle bumped into an aircraft its twin would react in the same way, even if it never left the laboratory. Work out a way to read that behaviour, and an image could be built up, even with no information being directly transmitted from the target.
The patent application itself suggests that by entangling waves of different characteristics the radar can decipher one by observing the other. In this way the frequency which cannot travel far can pass on the information to the frequency which can. It is a kind of information relay race in which the baton started by things which can look through walls, see IEDs emplaced underground and past stealthy coatings can be passed to something which can reach the radar receiver. The saying that you can run but can’t hide may be truer than ever.
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”.
Research into quantum entanglement is at the heart of a revolution in understanding just how things happen and while knowledge of that process remains incomplete, developments this area are already changing cryptography, communication and computation. Recently DARPA has solicited research which can show “beyond any doubt that manifestly quantum effects occur in biology, and demonstrate through simulation proof-of concept experiments that devices that exploit these effects could be developed into biomimetic sensors.” Biomimetic sensors are “devices, or systems that imitate nature … of special interest to researchers in nanotechnology, robotics, artificial intelligence (AI), the medical industry, and the military.” What Albert Einstein called “spooky action at a distance” is rapidly becoming part of the technology because it seems to work though don’t quite understand it.
The impact of these new ideas will eventually spread past the hard sciences and technology into our zeitgeist. Popular culture is still largely based on 19th century physical concepts, on the ‘common sense’ of the 1920s. It is bound to be modified by our new knowledge. Sir Arthur Eddington once said that “not only is the universe stranger than we imagine, it is stranger than we can imagine”. That is probably because we only see part of it and are perplexed and surprised when the balance comes into view. And now that 21st century science is bringing more of the strangeness to the surface I think we will find a remarkable willingness in the public to embrace it.
One of my favorite works of fantastic literature is an early 20th century story called The Charwoman’s Shadow, which is all about a young man’s attempts to restore an old woman’s shadow to herself because as it turns out, the least obviously valuable part of us is what is most important. The shadow was entangled with her; and a sorcerer by holding it in his keeping kept her in his thrall. You know, sort of like quantum radar. That today’s public might receive that comparison as more than poetic license stems from its exposure to the information revolution. This is the first generation that understands the value of the invisible, that knows the secret power pattern can impose on the inanimate; which grasps the relationship of software to hardware and who, perhaps for the first time since the electric light dispelled the shadows of night, can sense the ghost in the machine by the full light of day.
Arthur Clarke once wrote that “the only way of discovering the limits of the possible is to venture a little way past them into the impossible,” and that moreover, “any sufficiently advanced technology is indistinguishable from magic.” The magic is back. The hard part is being able to stay on our feet in its midst.
So the 21st century threatens to reverse the tremendous set piece on which the Charwoman’s Shadow ended, with the defeated sorcerer fleeing over the Pyrenees, summoning everything magical in the world after him to hide forever in the Land Beyond the Moon’s Rising. Perhaps for a while, but not for all time. A century which taught that the loss of magic was the price of enlightenment has given way to one in which marvels and perils we thought imaginary now rise before us into dark and wondrous heights and we must nerve ourselves to meet them.