Intel Labs has detailed a handful of technical features of its new cryogenic quantum control chip, Horse Ridge, touting that it addresses fundamental challenges behind building quantum systems that are powerful enough to demonstrate "quantum practicality".
"Today, quantum researchers work with just a small number of qubits, using smaller, custom-designed systems surrounded by complex control and interconnect mechanisms," Intel Labs director of quantum hardware Jim Clarke said.
"Intel's Horse Ridge greatly minimises this complexity. By systematically working to scale to thousands of qubits required for quantum practicality, we're continuing to make steady progress toward making commercially viable quantum computing a reality in our future."
The semiconductor giant and QuTech -- a partnership between TU Delft and the Netherlands Organization for Applied Scientific Research (TNO) -- detailed in a research paper that where scalability is concerned, the integrated System-on-a-Chip design can integrate four radiofrequency (RF) channels into a single 4x4mm device. According to Intel, this was achieved by using Intel's 22nm FFL CMOS technology.
The company added that each channel could control up to 32 qubits to leverage "frequency multiplexing" -- a technique described by Intel as dividing the total bandwidth available into a series of non-overlapping frequency bands -- each of which could be used to carry a separate signal.
"Leveraging these four channels, Horse Ridge can potentially control up to 128 qubits with a single device, substantially reducing the number of cables and rack instrumentations previously required," Intel said.
On fidelity, Intel saidincreases in qubit count can trigger other issues that challenge the capacity and operation of the quantum system.
One such potential impact is a decline in qubit fidelity and performance.
"In developing Horse Ridge, Intel optimised the multiplexing technology that enables the system to scale and reduce errors from 'phase shift' -- a phenomenon that can occur when controlling many qubits at different frequencies, resulting in crosstalk among qubits," the company explained.
According to Intel, the various frequencies Horse Ridge leverages can be "tuned" with high levels of precision, enabling the quantum system to adapt and automatically correct for phase shift when controlling multiple qubits with the same RF line, thus improving qubit gate fidelity.
Horse Ridge is also touted as offering flexibility, that is, covering a wide frequency range to enable control of both superconducting qubits -- known as transmons -- and spin qubits.
Transmons typically operate around 6 to 7GHz, while spin qubits operate around 13 to 20GHz.
"Intel is exploring silicon spin qubits, which have the potential to operate at temperatures as high as 1 kelvin. This research paves the way for integrating silicon spin qubit devices and the cryogenic controls of Horse Ridge to create a solution that delivers the qubits and controls in one streamlined package," Intel said.