Feeds

Spooky action at a distance is faster than light

Chinese boffins put the clock on information transfer between entangled particles

Bridging the IT gap between rising business demands and ageing tools

As Einstein put it, it's impossible for anything – even information – to move faster than the speed of light. Yet the lower bound of that impossibility, the minimum speed at which entanglement can't possibly be transmitting information between two particles, appears to be around four orders of magnitude higher than c, the speed of light in a vacuum.

When describing his objections to quantum physics, one of Einstein's thought experiments was to consider the creation of a pair of entangled particles, which would retain the property of entanglement no matter how great the distance that might later separate them: the state of each entangled particle would somehow affect the other, no matter how great the distance separating them.

As far as Einsten was concerned, that was a no-no, since keeping entanglement intact demanded information transfer take place at greater than the speed of light – a violation of the general relativity.

So: since we know that entanglement exists (it's been observed and is the basis of so-called "quantum teleportation"), it's perfectly reasonable to ask at what rate the information transfer is violating general relativity?

According to this paper at Arxiv, once Earth's inertial frame of reference is taken into account, the lower bound of the speed of “spooky action” is 1.38 x 104 the speed of light in a vacuum.

The researchers say that to guarantee that what they were measuring was truly the result of entanglement – and not, for example, the outcome of coincidence – they needed to set at least one record, and observe a continuous violation of Bell's inequality for 12 hours.

Experimental setup for measuring the speed of spooky action

Source: University of Science and Technology of China

Since there needs to be enough separation between the two entangled photons as to enable a valid measurement of how long the entangled behaviour seems to pass from one particle to another, they also needed sufficient separation between the two ends of the experiment.

The researchers, from the Department of Modern Physics at the University of Science and Technology, China in Shanghai, separated their “Bob and Alice” photon detectors by 16 Km in the Qinghai Lake province: one device was placed at a scenic lookout, the other at a fish farm. Between the two is the photon source and its associated equipment.

To keep the experiment operation for 12 hours, the researchers say they created a tracking system ensuring that the signals weren't lost, and conducted the experiment at night-time so they didn't have to cope with daylight. ®

Mobile application security vulnerability report

More from The Register

next story
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
Mwa-ha-ha-ha! Eccentric billionaire Musk gets his PRIVATE SPACEPORT
In the Lone Star State, perhaps appropriately enough
All those new '5G standards'? Here's the science they rely on
Radio professor tells us how wireless will get faster in the real world
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Microsoft's anti-bug breakthrough: Wire devs to BRAIN SCANNERS
Clippy: It looks your hands are shaking, are you sure you want to commit this code?
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.