Quantum Teleportation, Not quite Beam me Scotty!
Scientists at The University of Geneva have successfully teleported a particle of light 25km. While it’s not exactly “Beam me up Scotty” material, Quantum Teleportation is still pretty cool. Computers are being built off this new technology, and they will shape the future of our communications.
I was quite a Star Trek fan as a kid. To be honest, it was just any science fiction. From Star Wars to Alex Mack, I loved it all. And while I’ve gotten taller, I haven’t really grown up. My inner-kid still gets super excited when any new scientific development resembles a gadget from my childhood. So when I heard about teleportation, I knew I had to find out more.
Quantum Mechanics is essentially the physics of the very very small. For example, it’s how electrons, protons as well as photons (particles of light) work. When you get down to this level, things don’t behave in a classical, or Newtonian, way.
To demonstrate this point, we have the “Schrodinger’s Cat Thought Experiment”. Erwin Schrodinger was an extremely prominent Quantum Physicist in the early 1900’s. He came up with this rather morbid thought experiment in 1935. A cat is put in a box where nobody can observe it. A contraption is set up which will let out a poisonous gas in the event that a particle decays. Quantum mechanics says that the particle is in a combination of states until an observation has been made. This means that the particle has both decayed and not-decayed at the same time. Which also means, that while the box is still closed, the cat is both dead and alive simultaneously. Like some dodgy, zombie apocalypse film.
Another area in quantum mechanics which is a little weird is called Entanglement. This is where two particles are connected in some unknown and spooky way. Think of two people on a seesaw. As one goes up, the other automatically goes down. Particles each have certain intrinsic properties which make them identifiable. For example, the charge is defined as positive (ie. a proton) or negative (an electron). Scientists also look at a property called spin, which describes the angular momentum of the particle. A particle is said to be either spin up or spin down. When two particles have become entangled, if one of them has spin up, the other must be spin down. The change of state of one automatically affects the state of the other, irrespective of distance. There is some unknown inner connection between the two.
The actual act of quantum teleportation is not what you would probably think. It’s almost more of a copy that is produced. Say you have a pair of entangled photons. Putting them in separate cardboard boxes, one is given to Alice, the other to Bob. Alice takes a peek at hers, and in doing so determines what state it is in. Bob then knows, without opening his lightweight delivery, exactly what is inside.
The new results in Geneva use a crystal as a type of storage device to teleport a photon. Rather than Alice and Bob, one of the entangled photons is sent to a crystal, while the other is sent along a rather long piece of optical fibre (25km to be exact). Yet another photon is sent after the second along the line of optical fibre, crashing into it and destroying both of them. The University of Geneva found that the information wasn’t destroyed on impact though, and was actually sent to the entangled pair in the crystal. The information is teleported instantaneously across this distance.
These crystals are home to the photonic information which is teleported. © GAP, University of Geneva (UNIGE). More info at Eurekalert.org
There is still a long way to go in quantum computing and communications, but this is an important step forward. A world of quantum computing would find us with ultrafast and extremely secure communications and networks.