Namibian cuprous oxide gemstone could hold key to quantum computers

Cuprous oxide – the mined crystal from Namibia used for making Rydberg polaritons. (Image courtesy of University of St Andrews).

New research led by the UK’s University of St Andrews found that a special form of light made using an ancient Namibian gemstone could be the key to new light-based quantum computers, which could solve long-held scientific mysteries.

In detail, the study found that using a naturally mined cuprous oxide (Cu2O) gemstone from Namibia it is possible to produce Rydberg polaritons, the largest hybrid particles of light and matter ever created.

Rydberg polaritons switch continually from light to matter and back again. In Rydberg polaritons, light and matter are like two sides of a coin, and the matter side is what makes polaritons interact with each other.

This interaction is crucial because this is what allows the creation of quantum simulators, a special type of quantum computer, where information is stored in quantum bits. These quantum bits, unlike the binary bits in classical computers that can only be 0 or 1, can take any value between 0 and 1. They can therefore store much more information and perform several processes simultaneously.

Solving science mysteries

In a paper published in the journal Nature Materials, the researchers behind the discovery explain that this capability could allow quantum simulators to solve important mysteries of physics, chemistry and biology: for example, how to make high-temperature superconductors for highspeed trains, how cheaper fertilizers could be made potentially solving global hunger, or how proteins fold making it easier to produce more effective drugs.

“Making a quantum simulator with light is the holy grail of science,” project lead Hamid Ohadi, said in a media statement. “We have taken a huge leap towards this by creating Rydberg polaritons, the key ingredient of it.”

To create Rydberg polaritons, the researchers trapped light between two highly reflective mirrors. A cuprous oxide crystal from a stone mined in Namibia was then thinned and polished to a 30-micrometre thick slab and sandwiched between the two mirrors to make Rydberg polaritons 100 times larger than ever demonstrated before.

Following this work, the team decided to further refine these methods in order to explore the possibility of making quantum circuits, which are the next ingredient for quantum simulators.