Synopsis: Linked in

A link in a quantum network is built from a hybrid atomic system, connected by fiber optics.
Synopsis figure
M. Lettner et al., Phys. Rev. Lett. (2011)

Networks provide an essential tool for many communication and computational tasks by connecting different regions of space to allow remote systems to talk to one another. In a quantum network, a link represents shared entanglement between remote systems. Establishing such a link involves the creation, distribution, storage, and retrieval of entanglement.

Writing in Physical Review Letters, Matthias Lettner and colleagues from the Max Planck Institute for Quantum Optics in Garching, Germany, report they are able to create such a link with a notably high fidelity of 95%. (Fidelity characterizes the reproducibility of preparing a quantum state.) They entangle two systems that sit in different laboratories located 13 meters apart. In one laboratory, they send a laser pulse onto a single Rubidium atom inside an optical cavity to create a photon that is entangled with the atom. The photon is allowed to depart the cavity to travel through 30 meters of optical fiber to another laboratory. There, a Bose-Einstein condensate (BEC) of Rubidium atoms captures the photon and stores it in the multi-atom wave function, creating an entangled state between the single atom and the atomic ensemble. Two final steps map the atom-BEC entanglement onto photon-photon entanglement: retrieving the stored photon from the BEC and, meanwhile, producing a second photon from the single atom.

This hybrid system, which demonstrates the creation, distribution, storage, and retrieval of entanglement across remote locations, is an essential link within, and a step towards, a real-world quantum network. – Sonja Grondalski


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsQuantum Information

Previous Synopsis

Next Synopsis

Related Articles

Synopsis: Direct View of Exchange Symmetry
Quantum Physics

Synopsis: Direct View of Exchange Symmetry

A proposed set of experiments could offer a direct measurement of the fundamental quantum property that distinguishes fermions from bosons. Read More »

Synopsis: Topological Defect on the Move
Condensed Matter Physics

Synopsis: Topological Defect on the Move

Researchers have directed the motion of a domain-wall-like topological defect through a crystal of trapped ions. Read More »

Viewpoint: Trapped Ions Test Fundamental Particle Physics
Atomic and Molecular Physics

Viewpoint: Trapped Ions Test Fundamental Particle Physics

New precision experiments using trapped molecular ions provide an alternative method for determining if the electron has an electric dipole moment. Read More »

More Articles