‘Think of it like a snow globe’
Quantum information technology leverages quantum mechanics to process, store, and transmit information in ways that classical systems cannot. At the heart of this technology are collections of qubits, known as qubit systems. In one such system, solid host materials like diamond or moissanite retain quantum information through atomic defects that serve to trap electron spins. These gemstones’ transparent properties help isolate these qubits in a manner stable enough for manipulation.
“Think of it like a snow globe; the glass of the snow globe protects the objects from outside disturbances, yet we are still able to manipulate it when we shake it,” says Manato Kawahara, a PhD course student at Tohoku University’s Research Institute for Electrical Communication (RIEC) and first author on the new paper.
“In the case of qubits, we use magnetic or electric fields to control the spin of the qubit,” he said.
Kawahara and his colleagues’ breakthroughs were aided by previous research from the University of Chicago, Argonne National Laboratory, and Tohoku University. In 2021, a research group developed guidelines for finding new solid-state spin qubit systems, and in 2022, the same group unveiled a means of streamlining the discovery of viable qubit materials.
This led the current group to spinel, which they were able to experimentally test by directing a laser beam onto the material to excite it, and then measuring the emitted light (photoluminescence) to analyze the material's response.
However, to be fully operational for the qubit, the system needs to demonstrate three functions: initialization, manipulation, and detection. The findings here demonstrate that spinel possesses the first and third functions, i.e., the ability to initialize and read the qubit state.
“Looking forward, we plan to manipulate and control the spin qubit for emerging quantum applications across sensing, communication, and computing,” Awschalom said.