Written by James Orme Wed 19 Feb 2020

Intel says Horse Ridge chip brings commercially viable quantum computing one step closer

Intel has unveiled a new cryogenic quantum chip that it claims marks a “milestone in the development of a commercially viable quantum computer”.

The chipmaker outlined the technical features of the “Horse Ridge” chip in a research paper released at the 2020 International Solid-State Circuits Conference (ISSCC) in San Francisco.

Intel said the chip could be used to build a quantum computing system powerful enough to satisfy the three conditions of quantum practicality: scalability, flexibility and fidelity.

Quantum computers leverage qubits instead of bits to solve problems that ordinary computers would take millions or even billions of years to solve. Drug development, materials design and weather forecasts are some of the tasks that quantum computers could accelerate.

Until now quantum frontrunners like IBM and Google have been busy creating systems that demonstrate quantum supremacy, the moment a quantum computer outperforms the best conventional computer, rather than building systems capable of solving practical problems.

That’s mainly because today’s quantum chips don’t store enough qubits to solve practical tasks (the largest hold around 20). Intel’s new chip is an altogether different beast. Horse Ridge can potentially control up to 128 qubits with a single device.

“Today, quantum researchers work with just a small number of qubits, using smaller, custom-designed systems surrounded by complex control and interconnect mechanisms,” said Jim Clarke, director of quantum hardware, Intel Labs.

“Intel’s Horse Ridge greatly minimizes 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,” he added.

The chip can operate on this scale thanks to its System on Chip (SoC) design that integrates four radio frequency (RF) channels into a single device, each capable of controlling up to 32 qubits. A technique called “frequency multiplexing” ensures the total bandwidth available is divided into non-overlapping frequency bands, which each carry a separate signal. Hence, leveraging these four channels Horse Ridge can potentially control up to 128 qubits with a single device.

When the volume of qubits increases, systems run the risk of upending “quantum fidelity” — the ability to discern between quantum states. Fidelity is another condition Intel thinks its new chip can satisfy. According to the chipmaker, its latest “multiplexing” technology reduces errors and “cross-talk among qubits” that damages system performance.

Lastly, Intel claimed Horse Ridge guarantees quantum flexibility (the ability to process both transmon and spin qubits) by covering a wide frequency range. Transmons typically operate around 6 to 7 GHz, while spin qubits operate around 13 to 20 GHz.

“Intel is exploring silicon spin qubits, which have the potential to operate at temperatures as high as 1 kelvin,” the company added. “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 Labs developed the chip in collaboration with QuTech ‑ a partnership between TU Delft and TNO (Netherlands Organization for Applied Scientific Research).