Spooky action at a distance is faster than light

Chinese boffins put the clock on information transfer between entangled particles

Beginner's guide to SSL certificates

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. ®

Remote control for virtualized desktops

More from The Register

next story
MEN: For pity's sake SLEEP with LOTS of WOMEN - and avoid Prostate Cancer
And, um, don't sleep with other men. If that's what worries you
Voyager 1 now EIGHTEEN LIGHT HOURS from home
Almost 20 BEEELION kilometres from Sol
Jim Beam me up, Scotty! WHISKY from SPAAACE returns to Earth
They're insured for $1m, before you thirsty folks make plans
Er, we think our ISS launch beats your fishing expedition
NASA: Spacecraft crash site FOUND ON MOON RIM
'What fun!' exlaims NASA boffin who found the LADEE
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
BAE points electromagnetic projectile at US Army
Railguns for 'Future fighting vehicle'
OK Google, do I have CANCER?
Company talks up pill that would spot developing tumors
prev story


Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
How to simplify SSL certificate management
Simple steps to take control of SSL certificates across the enterprise, and recommendations centralizing certificate management throughout their lifecycle.