Researchers from the Physikalisches Institut of the University of Stuttgart have create entangled quantum states in diamond, which means there is finally a diamond men care about - namely the one that might some day be inside a quantum computer working at room temperature, a feat so far considered impossible for other materials.

While physicists have long described the world of atoms by quantum mechanics, one of its strangest characteristics, and the one that defies easy description, allows the linking of two objects without any noticeable interaction over a distance.

Einstein called this a 'spooky interaction.'

One of the most spectacular experiments based on this unusual entanglement characteristic is quantum teleportation, where the properties of one quantum object are transferred to another one at a remote location.



One percent of the carbon atoms in the diamond lattice possess a magnetic moment, presented as a green arrow. These would be the quantum-bits in a hypothetical diamond-based quantum computer. (picture: Universität Stuttgart)

But this effect is very sensitive to any perturbations so physicists have to work under extreme conditions like temperatures close to absolute zero to entangle quantum objects. Apparently this is not necessary in diamond, say the scientists from Stuttgart. In their experiments they shot nitrogen atoms into the diamond lattice at high speed. These impurities are detectable by their fluorescence and they change the diamond color to pink. Because of its unmatched stiffness the diamond lattice is shielding the Nitrogen atoms and thus allows detecting quantum effects such as entanglement under ambient conditions.

This gave the researchers from Stuttgart the opportunity to create suitable quantum states among the building blocks of the diamond lattice, namely the carbon atoms. One percent of those carbon atoms possess a magnetic moment what allows them to interact with an implanted nitrogen atom in close vicinity. This interaction was used to individually address the carbon atoms which have been entangled in the end.

Ultrafast quantum computers using spooky action still have some distance to travel but this could end up being a major milestone.

Article: Philipp Neumann, Norikazu Mizuochi, Florian Rempp, Philip Hemmer, Hideyuki Watanabe, Satoshi Yamasaki, Vincent Jacques, Torsten Gaebel, Fedor Jelezko, Jörg Wrachtrup: 'Multipartite Entanglement Among Single Spins in Diamond' – SCIENCE, 6 June 2008, Vol. 320, Issue 5880