A team of Physicists are in the process of developing a prototype quantum hard drive that has the capability to improve storage time by a factor of more than 100. The team’s record storage time of six hours is a huge step forwards towards a secure worldwide data encryption network that is based on quantum information This breakthrough in quantum hard drives could be used for banking transactions and personal emails in the future.
The lead author Manjin Zhong, from the Research School of Physics and Engineering (RSPE) said, “We believe it will soon be possible to distribute quantum information between any two points on the globe…Quantum states are very fragile and normally collapse in milliseconds. Our long storage times have the potential to revolutionise the transmission of quantum information.”
Quantum information brings the possibility of ‘unbreakable’ encryption because quantum particles, such as photons of light, can be created in such a way that intrinsically links them. Interactions with any of these entangled particles affect the other, no matter how far they are separated.
The team of physicists at ANU and the University of Otago have stored some quantum information in atoms of the rare earth element europium embedded in a crystal.
This solid-state technique is a possible alternative to using laser beams in optical fibres, an approach which is currently used to create quantum networks around 100 kilometres long.
Ms Zhong said, ”Our storage times are now so long that it means people need to rethink what is the best way to distribute quantum data…Even transporting our crystals at pedestrian speeds we have less loss than laser systems for a given distance…We can now imagine storing entangled light in separate crystals and then transporting them to different parts of the network thousands of kilometres apart. So, we are thinking of our crystals as portable optical hard drives for quantum entanglement.”
Following writing a quantum state onto the nuclear spin of the europium using laser light, the researchers then subjected the crystal to a amalgamation of fixed and oscillating magnetic fields in order to preserve the quantum information.
Dr Jevon Longdell of the University of Otago said, ”The two fields isolate the europium spins and prevent the quantum information leaking away.”
Associate Professor Matthew Sellars, leader of the research team, said, “We have never before had the possibility to explore quantum entanglement over such long distances…We should always be looking to test whether our theories match up with reality. Maybe in this new regime our theory of quantum mechanics breaks.”
The ANU group is also excited about the fundamental tests of quantum mechanics that a quantum optical hard drive will enable. The team’s research is published in Nature.
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