In the study, a team of physicists demonstrated that they could read signals from a type of qubit called a superconducting qubit, as well as without damaging the qubit, using laser light.
The team’s findings could be an important step in building quantum networks, the researchers said. Such a network could connect masses or hundreds of quantum chips, allowing engineers to solve problems beyond the reach of even the fastest computers today. In theory, they could use the same set of tools to send longer running code.
The study, which will appear June 15 in the journal Nature, was led by the District, a joint research center between CU Boulder and NIST.
“Currently, there is no way to send a quantum signal between remote superconducting processors like we send a signal between two classical computers,” said lead author of the study and a graduate student in the District, Robert Delaney.
Delaney explained that the traditional pieces your laptop computer can use are very limited: they can only take the number of zeros or ones, which is the raw number of most computer programs to date. Qubits, in contrast, can exist as zeros, singles, or, by a structure called “superposition,” and they can be together.
But working with qubits is also like trying to hold an ice cube in your hot hand. Even the slightest disturbance can tear the top, making them look like normal pieces.
In a new study, Delaney and her colleagues show they can overcome those vulnerabilities. The team uses a thin layer of silicon and nitrogen to convert the signal from a superconducting qubit into visible light – the same type of light that already carries digital signals from one city to another via fiberoptic cables.
“Researchers have conducted experiments to remove visible light from the qubit, but not interfering with the qubit in the system is a challenge,” said fellow study author Cindy Regal, a JILA associate and associate professor of physics at CU Boulder.