This won't please the Israeli Air Force . . .

The ferociously effective Israeli Air force has developed an international reputation over many years for exploiting any and every weakness in an opponent's armory in order to accomplish its mission(s).  This includes jamming, spoofing and rendering useless enemy air defense systems and technology, most famously in recent years in Operation Orchard, the 2007 air strike that destroyed a North Korean-built nuclear reactor in Syria.  It's alleged that more recently, Israeli aircraft attacked a weapons convoy in the Sudan in 2009, and destroyed a weapons storage facility there in October this year.  However, that nation has few air defenses, so one assumes that massive electronic countermeasures weren't required for those operations.

I'm therefore sure that the Israeli Air Force is carefully studying a report of a new radar system that's allegedly impervious to jamming.  MIT's Technology Review reports:

Physicists have exploited the quantum properties of photons to create the first imaging system that is unjammable.

. . .

... their idea is to use polarised photons to detect and image objects. Reflected photons can of course be used to build up an image of the object. But an adversary could intercept these photons and resend them in a way that disguises the object’s shape or makes it look as if it is elsewhere.

However, such a process would always change the quantum properties of the photons such as their polarisation. And so it should always be possible to detect such interference. “In order to jam our imaging system, the object must disturb the delicate quantum state of the imaging photons, thus introducing statistical errors that reveal its activity,” say Malik and co.

That’s more or less exactly how quantum key distribution for cryptography works. The idea here is that any eavesdropper would change the quantum properties of the key and so reveal his or her presence. The only difference in the quantum imaging scenario is that the “message” is sent and received by the same person.

 Malik and co have tested their idea by bouncing photons off an aeroplane-shaped target and measuring the polarisation error rate in the return signal. Without any eavesdropping the system easily imaged the aeroplane.

But when an adversary intercepted the photons and modified them to send back an image of a bird, the interference was easy to spot, say Malik and co.

There's more at the link.  The full research paper on which the MIT report is based may be found here (link is to an Adobe Acrobat document in .PDF format), but don't bother trying to make sense of it unless you're of the genus eggheadus.

I'm very interested to read of this development.  I'd imagine, around about now, some Israeli scientists are being tasked to come up with a way to interfere with quantum-propertied photons and nullify this discovery.  Given the way Iran's been carrying on lately, perhaps Israel has already succeeded in converting Persian quantums into tantrums?





Peter