New quantum computer chip created

Researchers at the California Institute of Technology have created a computer chip with nanoscale optical quantum memory.

The quantum chip, the smallest ever made, is able to store data more efficiently and securely than a usual computer chip. The researchers achieved this by taking advantage of quantum physics peculiarities, such as superposition, where a quantum element can exist in two distinct states simultaneously.

Andrei Faraon, assistant professor of applied physics at Caltech and co-author of the study, said: “Such a device is an essential component for the future development of optical quantum networks that could be used to transmit quantum information.”

The new memory chip is similar to a traditional memory chip that stores information as either a 1 or 0 – known as a bit. Quantum devices however are able to exist in multiple states at the same time. This means that a quantum bit – or qubit – can exist as a 1 and 0 at the same time.

In order to store photons, Faraon’s team created memory modules using optical cavities made from rare-earth ion doped crystals. Each module was then cooled to almost absolute zero (-273°C) before a heavily filtered laser fired single photons into it. The rare earth ions efficiently absorbed the photons.

The photons were released 75 nanoseconds later and checked to see whether they had retained informed recorded on them – 97% of the time, they had. Tian Zhong, lead author of the study, also from Caltech, said: “This technology not only leads to extreme miniaturisation of quantum memory devices, it also enables better control of the interactions between individual photons and atoms.”

The study was published in Science.