Researchers from the University of Calgary, Canada, teleported the state of a photon (particle of light) over a six kilometer distance through a “dark fiber” cable. The accomplishment set a new record in quantum teleportation, getting us a little closer to having quantum networks, and ultimately a quantum internet.
Rise Of Quantum Systems
Over the past few years, research into quantum computers and quantum networks has increased as more academics and technology companies began to believe that we may be close to figuring out just how to make these systems work, and then use them outside of the lab.
We’ve had D-Wave announce a more specialized type of quantum computer, and upgrading it every few years. More recently, we’ve had IBM and Google announce their working universal quantum computers. We’ve also had research that showed quantum computers could be built on silicon (as opposed to more expensive materials). Even the NSA has begun warning that the day when quantum computers will break existing forms of encryption is sooner than we think.
Quantum networks are a somewhat different area of research, but still relevant to the quantum field as a whole. If we can teleport information, we may be able to drastically increase the amount of information we can send through networks, and the speed at which we send it, too.
A quantum internet would be beneficial to quantum computers in the same way our regular internet is beneficial to traditional computers. Quantum networks could also aid in protecting communications against eavesdropping, although the jury is still out on how effective that would actually be.
The experiment done by the researchers from the University of Calgary involves using quantum “entanglement,” a process they explain below:
“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” explained Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary and leader of the project.“When one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary.”The photon whose state was teleported to the university was then generated in a third location in Calgary, and then it also traveled to the City Hall, where it met the photon that was part of the entanglement pair.“What happened is the instantaneous and disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,” said Tittel.
Tittel’s group had to overcome some significant challenges along the way. One of the main issues concerned how the variable temperature outside would change when the photons would arrive at City Hall. The two photons were eventually timed to arrive within 10 picoseconds of each other, which is one trillionth--that is, one millionth of one millionth--of a second.
Towards A Global Quantum Internet
The long-term goal of the Tittel group is to create the basic building blocks for a global quantum internet. The City of Calgary will aid in this task by offering access to “dark fiber,” which got its name from its composition; it’s a single optical cable with no electronics or equipment to interfere with the quantum technology.
"By opening The City’s dark fiber infrastructure to the private and public sector, non-profit companies, and academia, we help enable the development of projects like quantum encryption and create opportunities for further research, innovation and economic growth in Calgary,” said Tyler Andruschak, project manager with Innovation and Collaboration at The City of Calgary.“The university receives secure access to a small portion of our fibre optic infrastructure and The City may benefit in the future by leveraging the secure encryption keys generated out of the lab’s research to protect our critical infrastructure. In order to deliver next-generation services to Calgarians, The City has been increasing its fibre optic footprint, connecting all City buildings, facilities and assets,” added Andruschak.
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If we build too many quantum systems and networks, we're going to lag the simulation. :( Keep it simple guys. Nobody likes stuttering. Imagine everything lagging while you're in traffic. Terrible!Reply
hmm "dark fibre" is an existing term that just means a piece of fibre you own or lease, instead of purchasing bandwidth on someone else's existing network (more common). Are they adding a new definition or just using their dark fibre in a new way?Reply
But something I don't understand about these entanglement experiments is how the two photons in the pair are actually separated... in layman's terms: do you put a photon in some sort of fancy "jar" that stops it from flying off and bouncing off the nearest cat photo, and physically transport it the 6 kilometers away to City Hall?
Perhaps their "dark fibre" is still traditional definition: it's a piece of fibre they own, and like article says, they have kept it "bare" without any equipment because that's what's needed for their experiment? The photon from the pair is actually transported on this dark fibre?
In order to be considered teleportation, whatever photon was sent down the dark fibre, would have to then be stored/contained in preparation for the experiment: the quantum transfer on information from university photon and the city hall photon... otherwise it's just sending light down fibre like any other fibre connection, but measuring it differently?
In other words, I would imagine, the eventual "end game" is to have a large number of permanent photo pairs spread all around the world: you change one half of pair and the other half changes *bam* instant information transfer... if you need to transfer the photons to their destination before hand, via "dark fibre" or whatever, it kinda defeats the purpose right? Or maybe there's an initial send of say 64 photons from 64 pairs via normally fibre optics, and then those 64 photon pairs are used for information transfer for a certain period of time?
The entangled photons are generated through fancy beam-splitting optics. The photons themselves travel the 'slow' speed-of-light way through optical delay lines and fiber. It is only their entangled state which transmits instantaneously.18630354 said:But something I don't understand about these entanglement experiments is how the two photons in the pair are actually separated... in layman's terms: do you put a photon in some sort of fancy "jar" that stops it from flying off and bouncing off the nearest cat photo, and physically transport it the 6 kilometers away to City Hall?
I'm no physicist, but I've read that quantum communication still doesn't exceed the speed of light. I think the main benefits are the supposed security (yeah, I saw the link but didn't click it), as well as needing neither line of sight nor a physical link.18630449 said:It is only their entangled state which transmits instantaneously.
Being able to send entangled photons on lasers through space or dark fiber solves an important problem of how to keep replenishing the supply of entangled particles, as they eventually become disentangled.
For those who are curious: according to Google, it takes a little over 20 microseconds for light to travel 6 km.Reply
This is 2 million times longer than 10 picoseconds.
"one trillionth--that is, one millionth of one millionth--of a second"Reply
No, I'm pretty sure "a million of a million" is a "billionth". When are you people from the USA going to get it right? What you refer to of as a "billion" is "thousands of millions" when it should be "millions of millions".
In any case, very interesting news. I wonder how they are actually measuring the behavior of the protons. In my simple and very limited knowledge of quantum physics, all I know it's not about accurate measurements, but statistical measurements.
"The photon whose state was teleported."Reply
Please read the press release, and fix your headline.
You're right, some countries use "billion" to describe "a million millions," but internationally trillion seems to be the preferred term, and it's also what the Canadian researchers themselves used.
What the article actually states is the following:Reply
1) We will still be sending photons down a piece of fiber. nothing different than today
2) however we will be able to entangle a single photon with one left behind, send one on to the other side. Once it arrives the data on both photons will the same, entanglement.
Basically this is only serving one purpose, trying to use photon entanglement as a method to encrypt data. Nothing changes are far as latency, capacity, etc.
Today is the first day I have heard of an alternate naming scheme for numbers. Right up until moments ago I thought the entire world worked the same way.Reply
1,000 - thousand
1,000,000 - million
1,000,000,000 - billion
10^12 - trillion
10^15 - quadrillion
10^18 - quintillion
Meaning 1,000 multiplied 1,000,000 times would equal 1,000,000,000.
So a thousand millions would be a billion.
Sub kilo, mega, giga, tera, penta and so on for metric.
This all fits. Nice and tidy. Logical in my own little brain
But then I learn after a quick Wikipedia search the above is "short scale." And only applies to U.S., English Canada, and modern British. While "long scale" applies to continental Europe, older British, and French Canada.
Long scale confuses me a little. there is something called a "milliard" but other than that every "named" number is in increase of 10^6 instead of 10^3.