## Tuesday, September 20, 2016

### 7 Kilometers...

 Calgary has seen quantum communication brettA/Getty
Topics: Computer Science, Entanglement, Quantum Computer, Quantum Teleportation

A little math for perspective: 7 kilometers x 1,000 meters/1 kilometer x 39.37 inches/1 meter x 1 foot/12 inches x 1 mile/5,280 feet = 4.35 miles. Fiber optic cables typically have a range, and stations to repeat/boost the signals. This could be improved of course, and part of an infrastructure buildup that could spur the education industry K-12 and post secondary to prepare future workers for building a new communications architecture. A lot of automated and outsourced jobs are not coming back, and these likely wouldn't be frustrated by old money, like the fossil fuel industry does alternative energy.

A new world record for quantum teleportation has been set, bringing quantum communication networks that can stretch between cities a step closer. Two independent teams have transferred quantum information over several kilometres of fibre optic networks.

Being able to establish teleportation over long distances is a crucial step towards exchanging quantum cryptographic keys needed for encoding data sent over the fibres.

Quantum teleportation is a phenomenon in which the quantum states of one particle can be transferred to another, distant particle without anything physical traveling between them. It relies on a property called entanglement, in which measuring the state of one particle immediately affects the state of its entangled partner, regardless of the distance between them.

Conceptually, one way of doing teleportation involves three participants: say, Alice, Bob and Charlie. In order for Alice and Bob to exchange cryptographic keys, they have to first establish the capacity for teleportation, with Charlie’s help.

First Alice sends a particle (A) to Charlie. Bob, meanwhile, creates a pair of entangled particles (B & C), sends B to Charlie and holds on to C. Charlie receives both A and B, and measures the particles in such a way that it’s impossible to tell which particle was sent by Alice and which by Bob. This so-called Bell state measurement results in the quantum state of particle A being transferred to particle C, which is with Bob.

New Scientist:
Quantum teleportation over 7 kilometres of cables smashes record, Anil Ananthaswamy