quantum network tagged posts

On the way to Quantum Networks

Picture of the single atom trap. In the ultra-high vacuum glass cell a single Rubidium atom is captured, which later will be entangled with a photon. Photo: C. Olesinski/LMU
Picture of the single atom trap. In the ultra-high vacuum glass cell a single Rubidium atom is captured, which later will be entangled with a photon. Photo: C. Olesinski/LMU

Physicists at LMU, together with colleagues at Saarland University, have successfully demonstrated the transport of an entangled state between an atom and a photon via an optic fiber over a distance of up to 20 km – thus setting a new record.

‘Entanglement’ describes a very particular type of quantum state which is not attributed to a single particle alone, but which is shared between two different particles. It irrevocably links their subsequent fates together – no matter how far apart they are – which famously led Albert Einstein to call the phenomenon as “spooky action at a distance”...

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Ytterbium: The Quantum Memory of Tomorrow

The photo shows a rare-earth crystal that serves as quantum memory. The crystal is cooled to 3 degrees above absolute zero temperature. Credit: © UNIGE

The photo shows a rare-earth crystal that serves as quantum memory. The crystal is cooled to 3 degrees above absolute zero temperature.
Credit: © UNIGE

Quantum communication and cryptography are the future of high-security communication. But many challenges lie ahead before a worldwide quantum network can be set up, including propagating the quantum signal over long distances. One of the major challenges is to create memories with the capacity to store quantum information carried by light. Researchers at the University of Geneva (UNIGE), Switzerland, in partnership with CNRS, France, have discovered a new material in which an element, ytterbium, can store and protect the fragile quantum information even while operating at high frequencies...

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