quantum networks tagged posts

A new atomic device sends high-fidelity quantum information over fiber optic networks. Researchers have a new way to connect quantum devices over long distances, a necessary step toward allowing the technology to play a role in future communications systems.

While today’s classical data signals can get amplified across a city or an ocean, quantum signals cannot. They must be repeated in intervals — that is, stopped, copied and passed on by specialized machines called quantum repeaters...

An optical fiber that uses the mathematical concept of topology to remain robust, thereby guaranteeing the high-speed transfer of information, has been created by physicists.

Optical fibres are the backbone of our modern information networks. From long-range communication over the internet to high-speed information transfer within data centres and stock exchanges, optical fibre remains critical in our globalised world.

Fibre networks are not, however, structurally perfect, and information transfer can be compromised when things go wrong...

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”...

This is an illustration of a photon gun. A quantum dot (the yellow symbol) emits one photon (red wave packet) at a time. The quantum dot is embedded in a photonic crystal structure, which is obtained by etching holes (black circles) in a semiconductor material. Due to the holes, the photons cannot be emitted in all directions, but only along the waveguide, which is formed by omitting a number of holes. Credit: Illustration: Søren Stobbe, NBI

Advanced photonic nanostructures are well on their way to revolutionising quantum technology for quantum networks based on light. Researchers from the Niels Bohr Institute have now developed the first building blocks needed to construct complex quantum photonic circuits for quantum networks...