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China is building a radar that can see stealth bombers. Should we be worried?
Liam MannixApril 13, 2019 — 1.00pm
It is unusual to hear a scientist say their research project probably won’t work out.
But that explains how crazy quantum radar is.
It’s a sci-fi technology that can easily spot radar-cloaked stealth bombers. It turns the $1 trillion Joint Strike Fighter into a flying hunk of junk. China claims to already have a working system.
All that might be true – or none of it.
“One of the reason I’m pretty sure this got funded is because of these claims,” says Professor David Ottaway.
“I’m going into this with a lot of scientific scepticism.”
Professor Ottaway, a physicist at the Institute for Photonics and Advanced Sensing at the University of Adelaide, has just been commissioned by the Defence Department to work out if quantum radar is real.
And if it is real – should Australia be building one?
What is quantum radar?
Normal radar works by sending out pulses of radio waves. When the waves hit the target – say, a jetfighter – some of them are reflected back. Those that don’t hit a target fly away into the atmosphere.
By picking up only the waves that come back, a radar can accurately tell if something is out there.
“The problem”, says Professor Stephen Bartlett, “is it’s not that simple.”
“You get all sorts of other signals coming to you, from the atmosphere and other objects. If people are trying to jam your radar, they can send their own signals at you to try to confuse you.”
But a radar built on quantum physics promises to be unjammable, undetectable and unavoidable, thanks to something called ‘entanglement’.
Quantum physics is the physics of extremely small objects, the scale of atoms. At this level, all physical laws as we know them change, replaced with strange, impossible behaviour.
Quantum allows us to do things that should not be real – like teleportation, or moving objects through solid walls, or computers than can predict multiple possible futures.
Entanglement is another quantum magic trick.
If you entangle two particles, they become fundamentally linked. They share a trait - it could be how they spin, or their electrical charge - and wherever they are and whatever happens to them, that trait will always be identical.
A quantum radar splits those particles. One gets beamed out, the other is kept. Then the returned signal can be compared to the particle you kept.
If you’ve got a match, there is an aircraft out there somewhere.
No hiding in the skies
The real value of quantum radar is detecting stealth aircraft.
Stealth aircraft dodge radar by using special radar-absorbing paint and curved fuselages to reflect the radar signal away from the receiver.
You get a bit of signal back, but not enough signal returns to the radar to allow it to pick out the aircraft from everything else out there that could be reflecting your signal – like trees and mountains and clouds, or signal created by radar jammers.
But quantum radars would know exactly which returning signals are the right ones, because they have essentially a perfect copy. So you only need a tiny echo to be able to pick out an aircraft.
“With a very small amount of signal, you can have high confidence that’s really yours,” says Professor Bartlett, a quantum expert at the ARC Centre for Engineered Quantum Systems at the University of Sydney.
Effectively, this would render stealth planes such as the B-2 and Australia’s Joint Strike Fighter naked in the sky.
That’s what made the announcement from a Chinese company, issued late last year, that they’d developed a working quantum radar so concerning.
The company has not released any details, and researchers are sceptical of whether they have made any real progress.
“They claim they’ve done it. But there is so little detail that, from what we can see, it’s almost useless,” Professor Ottaway says.
Quantum radar still appears monstrously difficult to develop, the Professor says. Entanging two particles is one thing; how do you keep them entangled if you are shooting one at enemy planes? How do you store the other without damaging the entanglement?
Professor Ottaway is yet to be convinced it can be done at all, but says it must be assessed - "because if it can be done it will be a game changer".
Even if the claims are more hype than reality, China has positioned itself to be a leader in quantum technology, spending huge amounts to boost its research in the area. If a quantum radar is physically possible, it may not be long until China cracks the code.
https://www.smh.com.au/national/chi...ers-should-we-be-worried-20190412-p51dod.html
Liam MannixApril 13, 2019 — 1.00pm
It is unusual to hear a scientist say their research project probably won’t work out.
But that explains how crazy quantum radar is.
It’s a sci-fi technology that can easily spot radar-cloaked stealth bombers. It turns the $1 trillion Joint Strike Fighter into a flying hunk of junk. China claims to already have a working system.
All that might be true – or none of it.
“One of the reason I’m pretty sure this got funded is because of these claims,” says Professor David Ottaway.
“I’m going into this with a lot of scientific scepticism.”
Professor Ottaway, a physicist at the Institute for Photonics and Advanced Sensing at the University of Adelaide, has just been commissioned by the Defence Department to work out if quantum radar is real.
And if it is real – should Australia be building one?
What is quantum radar?
Normal radar works by sending out pulses of radio waves. When the waves hit the target – say, a jetfighter – some of them are reflected back. Those that don’t hit a target fly away into the atmosphere.
By picking up only the waves that come back, a radar can accurately tell if something is out there.
“The problem”, says Professor Stephen Bartlett, “is it’s not that simple.”
“You get all sorts of other signals coming to you, from the atmosphere and other objects. If people are trying to jam your radar, they can send their own signals at you to try to confuse you.”
But a radar built on quantum physics promises to be unjammable, undetectable and unavoidable, thanks to something called ‘entanglement’.
Quantum physics is the physics of extremely small objects, the scale of atoms. At this level, all physical laws as we know them change, replaced with strange, impossible behaviour.
Quantum allows us to do things that should not be real – like teleportation, or moving objects through solid walls, or computers than can predict multiple possible futures.
Entanglement is another quantum magic trick.
If you entangle two particles, they become fundamentally linked. They share a trait - it could be how they spin, or their electrical charge - and wherever they are and whatever happens to them, that trait will always be identical.
A quantum radar splits those particles. One gets beamed out, the other is kept. Then the returned signal can be compared to the particle you kept.
If you’ve got a match, there is an aircraft out there somewhere.
No hiding in the skies
The real value of quantum radar is detecting stealth aircraft.
Stealth aircraft dodge radar by using special radar-absorbing paint and curved fuselages to reflect the radar signal away from the receiver.
You get a bit of signal back, but not enough signal returns to the radar to allow it to pick out the aircraft from everything else out there that could be reflecting your signal – like trees and mountains and clouds, or signal created by radar jammers.
But quantum radars would know exactly which returning signals are the right ones, because they have essentially a perfect copy. So you only need a tiny echo to be able to pick out an aircraft.
“With a very small amount of signal, you can have high confidence that’s really yours,” says Professor Bartlett, a quantum expert at the ARC Centre for Engineered Quantum Systems at the University of Sydney.
Effectively, this would render stealth planes such as the B-2 and Australia’s Joint Strike Fighter naked in the sky.
That’s what made the announcement from a Chinese company, issued late last year, that they’d developed a working quantum radar so concerning.
The company has not released any details, and researchers are sceptical of whether they have made any real progress.
“They claim they’ve done it. But there is so little detail that, from what we can see, it’s almost useless,” Professor Ottaway says.
Quantum radar still appears monstrously difficult to develop, the Professor says. Entanging two particles is one thing; how do you keep them entangled if you are shooting one at enemy planes? How do you store the other without damaging the entanglement?
Professor Ottaway is yet to be convinced it can be done at all, but says it must be assessed - "because if it can be done it will be a game changer".
Even if the claims are more hype than reality, China has positioned itself to be a leader in quantum technology, spending huge amounts to boost its research in the area. If a quantum radar is physically possible, it may not be long until China cracks the code.
https://www.smh.com.au/national/chi...ers-should-we-be-worried-20190412-p51dod.html
