Single atoms have been spotted doing the quantum version of the random walk by physicists in Germany. This sighting of a “quantum walk” could help in the design of quantum search algorithms, or in the understanding of the transition from the quantum, microscopic world to the classical, macroscopic world.

Quantum Information Theory is the study of information-processing tasks such as storage and transmission of information, or manipulation of entanglement, using quantum-mechanical systems. Until very recently, the study of these processes was limited to the case in which the required resources, e.g. information sources, communication channels or entanglement resources, were assumed to be available for an infinite number of independent uses.

A team of physicists from Austria has sent pairs of entangled photons, which can be used to encrypt messages with complete security, between telescopes spaced 144km apart in the Canary Islands. The researchers say that preserving entanglement over this distance shows the feasibility of carrying out quantum cryptography using a worldwide network of satellites.

The realization of a universal quantum computer that can carry out arbitrary computations remains a long term goal. But the technologies developed so far enable us to perform so called quantum simulations. Here assemblies of directly controllable quantum particles form models for complex systems which are difficult to manipulate. A new, promising technique was now developed in the group of Professor Gerhard Rempe at the Max Planck Institute of Quantum Optics in Garching.