Have you ever been to Ytterby?

Difficulty    

by Sara Marzban

In this post I’m going to briefly describe the solid state system, namely rare-earth crystalline material, that the Tittel lab at Qutech is using to do all sorts of cool quantum communication experiments, including building the hardware required for an elementary link of a quantum repeater.

In this era of online communications, the security of transmitted and received information is extremely important. Quantum communication is an absolutely secure method of communication between points A and B. However, building these secure quantum communication networks has proven to be difficult. In a quantum communication network, fragile quantum states are transmitted between a transmitter (point A) and a receiver (point B). During transmission, decoherence can be introduced into the system, either from losses in the transmission line, absorption in the system or from environmental contamination. Some of the losses occurring over the full length of the transmission line scale exponentially with distance and as a consequence, quantum communication is restricted to a range of about 200 km, beyond which quantum states can no longer be reliably measured [1, 2, 3].
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