Researchers at MIT have developed a process to manufacture and integrate "artificial atoms" with photonic circuitry, and in doing so, are able to produce the largest quantum chip of its kind.
The atoms, which are created by atomic-scale defects in microscopically thin slices of diamond, allow for the scaling up of quantum chip production.
A turning point for quantum processors
The new development “marks a turning point” in the field of scalable quantum processors, Dirk Englund, an associate professor in MIT’s Department of Electrical Engineering and Computer Science, explained in a press release.
Millions of quantum processors will be required for the oncoming, much-hyped advent of quantum computing. This new research shows there is a viable way to scale up processor production, the MIT team says.
The qubits in the newly-developed chip are artificial atoms made from defects in diamond. These can be prodded with visible light and microwaves, making them emit photons that carry quantum information.
This hybrid approach is described by Englund and his colleagues in a study published in Nature. The paper details how the team carefully selected "quantum micro chiplets" that contained multiple diamond-based qubits and integrated them onto an aluminum nitride photonic integrated circuit.
The 'ultimate vision' for qubit systems
“In the past 20 years of quantum engineering, it has been the ultimate vision to manufacture such artificial qubit systems at volumes comparable to integrated electronics,” Englund explained. “Although there has been remarkable progress in this very active area of research, fabrication and materials complications have thus far yielded just two to three emitters per photonic system.”
Using their hybrid method, Englund and his team successfully built a 128-qubit system. In doing so, they made history by constructing the largest integrated artificial atom-photonics chip yet.
“It’s quite exciting in terms of the technology,” Marko Lončar, Tiantsai Lin Professor of Electrical Engineering at Harvard University, who was not involved in the study, told MIT News. “They were able to get stable emitters in a photonic platform while maintaining very nice quantum memories.”
The next step for the researchers is to find a way to automate their process. In doing so, they will enable the production of even bigger chips, which will be necessary for modular quantum computers and multichannel quantum repeaters that transport qubits over long distances, the researchers say.