Storing data in a state of quantum entanglement could hold enormous promise for securing our online information. Right now, though, we can only maintain these states for a short time before the entanglement fails. An Australian research team has found a way to store data for hours, not milliseconds: say hello to the world's first solid state quantum hard drive.
Conventional quantum networks typically rely on fibre optic cables and lasers to store entangled information. These networks can be up to 100 kilometres in diameter, but the laser-based system's quantum states usually last just a few milliseconds before they collapse. This new hard drive from physicists at ANU and the University of Otago can hold tangled data for up to six hours.
The team essentially created the ROM to the laser-based method's RAM by embedding an atom of europium (a rare earth element) into a crystal matrix. Quantum information can be "written" into the atom's spin state using lasers and stored there for hours by then subjecting the crystal a pair of magnetic fields — one fixed, one oscillating — which lock the atom's spin in place. "The two fields isolate the europium spins and prevent the quantum information leaking away," Dr Jevon Longdell of the University of Otago said in a press statement.
"We can now imagine storing entangled light in separate crystals and then transporting them to different parts of the network thousands of kilometres apart," said lead author Manjin Zhong. "We believe it will soon be possible to distribute quantum information between any two points on the globe."
Should quantum information systems really take off, it could one day lead to a global data encryption network. Since the spin states of two entangled atoms will always match regardless of how far apart they are, this quantum effect would prevent third parties from tampering with the data as any changes to one spin state would be instantly reflected in its partner. [ANU]