Researchers working under the EU-funded QUARTET project have been able to greatly improve the readout of data from digital memories thanks to ‘quantum entanglement’ – why is this important? It could result in major applications for digital storage devices and allow for the construction of memories with higher capacities in next-generation computers.
In an optical memory, bits are read by shining a laser beam over the reflecting surface of the disk. In the memory, each microscopic cell has one or two possible levels of reflectivity, representing the values ‘zero’ and ‘one’ of a bit. The laser beam reflected from the cell may be more or less intense depending on the value of the bit, with the intensity eventually being translated into an electrical signal. However, a common problem is that when the intensity of the beam becomes too low, such as when the disc increases speed, energy fluctuations prevent the correct retrieval of bits, introducing errors.
The QUARTET (Quantum readout techniques and technologies) study showed that by utilising more sophisticated light sources and using quantum entanglement, this completely removes the unwanted fluctuations. However, their results potentially have even further applications than just digital memories. They say the same principle can be used in spectroscopy and the measurement of biological samples, chemical compounds and other materials. “This an experimental demonstration of quantum advantage directly at the core of a fundamental task in computer engineering and information technology.” - Stefano Pirandola, professor of Quantum Computing and QUARTET project coordinator.