Quantum Entangled Communications

China has announced that it has successfully used ground and satellite-based quantum entangled particles to achieve what Einstein once called “spooky action at a distance”.  This is groundbreaking for a number of reasons, but before i get into that, a quick primer to bring you up to speed.  Apologies for the geek speak but bear with me.

In the 1930’s, Neils Bohr and Albert Einstein were in hot debate about quantum mechanics and how to reconcile it with existing mathematical models.  What was deeply troubling to Einstien was that certain aspects of quantum mechanics just didn’t make sense and were almost supernatural.

Quantum entanglement (a relatively new term) involves a pair of particles intrinsically linked at the quantum level such that a change in the state of one particle will immediately change the state of the other, regardless of the distance between them.  Einstein couldn’t reconcile this with special relativity and proposed that quantum mechanics was an incomplete model.  At the time, the technology wasn’t available to prove or disprove anything so they had to rely on math and thought experiments.

It is now possible to create a pair of quantum entangled particles through a process known as “Spontaneous Parametric Down-Conversion”.  This process can split photons into type II photon pairs with mutually perpendicular polarization (ie. one up one down).  If one of these protons is then moved far away from the other, they are still intrinsically linked at the quantum level, allowing instantaneous flipping of their polarity regardless of the distance between them.

If that sounds ludicrous and unintuitive to you then you’re in good company.  This “spooky action at a distance” has some interesting possibilities for Faster Than Light (FTL) communications, and a few other side benefits that the Chinese are no doubt trying to harness.

Firstly, think about it.  If we are to explore the remote parts of our solar system (or further) we need a way to communicate with probes and spacecraft across an expanse many times the distance from Earth to the sun (1 Astronomincal Unit, AU).

Bear in mind, the light from our sun takes about 8 minutes to travel that 1AU to Earth.  Communication over a very long distance has an increasing latency that makes interacting with a remote probe or exchanging information, health statistics, data, or video feeds with a remote crew very cumbersome.

It is essentially snail mail.

You send a packet of information (however big you want) but its going to take 8 minutes for every 1 AU the probe or spacecraft is away from the Earth base.  That is not going to be very interactive.

Remotely controlling a lander vehicle on Titan, Enceladus or even Pluto is going to be like playing a game of chess — move forward, wait for reponse, Ah damn, now we’re in a ditch.

However, with quantum entanglement, there is now a possibility to overcome that distance.  If two particles are entangled and their polarisation can be controlled and read at both ends, then we have a synchronous communication method (i.e. messages can be sent in both directions, but not at the same time).  However, if we create two pairs, one pair for tranmission in one direction and the other pair for receipt, then we have asynchronous communication.

This is effectively a bitstream, sending 1’s and 0’s, corresponding to polarised up and down states.  If we want to move from serial communication where each bit is sent one after the other, then we simply add more pairs, allowing parallel bit streams.

We would have encoding devices for transmission and decoders for receipt.  This converts the bitstream back into usable data, information and video feeds, just like our existing technologies in our home computers, mobile phones and disk drives.

Now of course, when I say “sent”, it’s no longer like snail mail, it’s like a phone call or skype video chat, except with no latency.  A remote video feed from a camera on the front of a rover could be “streamed” back to Earth, the pilot sitting (with coffee in hand) driving comfortably around the craters and ditches, his/her every movement being relayed in realtime to the rover’s motor and steering controls.

A remote manned base established on a far flung moon could really utilise this sort of realtime communication and it would be invaluable to assist the crew, monitor the mission and remotely control robotic assistants (virtual crew members?).

Now back to the Chinese.  They have achieved a communication with quantum entangled particles between Earth and orbit (previously had only been done between two land sites).  This is a new record but why would the Chinese want to do this with an Earth orbit satellite?

The communication latency to a satellite isn’t too much of a problem, but it is very desirable from a military or government point of view because it can’t be hacked.

The “bitstream” isn’t floating through the air like a wifi signal, it’s in the quantum domain.

It doesn’t need to be encrypted because it’s somewhere we can’t go and only between the two entangled particles.

I say it can’t be hacked, but that’s only by our measly 2017 standards.

Imagine if all our electronic communications, video feeds, internet and devices are quantum based and real-time.

I’ll stop short of matter transportation, Star Trek’s “beam me up Scotty” and wormholes.  We haven’t figured out how to do that yet.  But I feel we’re on the cusp of a new age.


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