Several quantum computing milestones have been hit in recent months, as Google claims to have proven quantum supremacy, Amazon joins a host of other firms in offering quantum computing as a service, and now Intel’s Horse Ridge control chip claims to make the technology scalable and commercial viable.
Intel Horse Ride is a cryogenic control chip that has the ability to handle multiple qubits. That means quantum computer manufacturers could scale towards larger systems that would provide more power, with Intel believing the technology could become commercially viable thanks to this new chip.
Jim Clarke, Intel’s director of Quantum Hardware, noted, “While there has been a lot of emphasis on the qubits themselves, the ability to control many qubits at the same time had been a challenge for the industry. Intel recognised that quantum controls were an essential piece of the puzzle we needed to solve in order to develop a large-scale commercial quantum system. That’s why we are investing in quantum error correction and controls. With Horse Ridge, Intel has developed a scalable control system that will allow us to significantly speed up testing and realise the potential of quantum computing.”
Intel developed Horse Ridge with QuTech, a partnership between TU Delft and TNO (Netherlands Organisation for Applied Scientific Research), and the chip is fabricated using the company’s 22nm FinFET technology.
Why does this all matter?
In the race to realise the power and potential of quantum computers, researchers have focused extensively on qubit fabrication, building test chips that demonstrate the exponential power of a small number of qubits operating in superposition. However, in early quantum hardware developments — including design, testing and characterisation of Intel’s silicon spin qubit and superconducting qubit systems — Intel identified a major bottleneck toward realising commercial-scale quantum computing: interconnects and control electronics.
With Horse Ridge, Intel promises a solution that will enable the company to control multiple qubits and set a clear path toward scaling future systems to larger qubit counts — a major milestone on the path to quantum practicality.
To date, researchers have been focused on building small-scale quantum systems to demonstrate the potential of quantum devices. In these efforts, researchers have relied on existing electronic tools and high-performance computing rack-scale instruments to connect the quantum system inside the cryogenic refrigerator to the traditional computational devices regulating qubit performance and programming the system.
These devices are often custom-designed to control individual qubits, requiring hundreds of connective wires into and out of the refrigerator in order to control the quantum processor. This extensive control cabling for each qubit will hinder the ability to scale the quantum system to the hundreds or thousands of qubits required to demonstrate quantum practicality, not to mention the millions of qubits required for a commercially viable quantum solution.
With Horse Ridge, Intel brings the qubit controls into the quantum refrigerator — as close as possible to the qubits themselves. It effectively reduces the complexity of quantum control engineering from hundreds of cables running into and out of a refrigerator to a single, unified package operating near the quantum device.
Designed to act as a radio frequency (RF) processor to control the qubits operating in the refrigerator, Horse Ridge is programmed with instructions that correspond to basic qubit operations. It translates those instructions into electromagnetic microwave pulses that can manipulate the state of the qubits.
Named for one of the coldest regions in Oregon, the Horse Ridge control chip was designed to operate at cryogenic temperatures — approximately 4 Kelvin. To put this in context, 4 Kelvin is only warmer than absolute zero — a temperature so cold that atoms nearly stop moving.
Today, a quantum computer operates at in the millikelvin range — just a fraction of a degree above absolute zero. But silicon spin qubits have properties that could allow them to operate at 1 Kelvin or higher temperatures, which would dramatically reduce the challenges of refrigerating the quantum system.
As research progresses, Intel aims to have cryogenic controls and silicon spin qubits operate at the same temperature level. This will enable the company to leverage its expertise in advanced packaging and interconnect technologies to create a solution with the qubits and controls in one streamlined package.