The Horse Ridge control chip is designed to be able to sit inside the quantum refrigerator used in many quantum computers and allow all the computations to be controlled from inside the refrigerator, removing a major bottleneck toward realizing commercial-scale quantum computing - interconnects and control electronics. The new research paper unveils key technical capabilities of Horse Ridge that address fundamental challenges in building a quantum system powerful enough to demonstrate quantum practicality: scalability, flexibility, and fidelity.
Horse Ridge, says the company, is designed to greatly simplify today's complex control electronics required to operate such a quantum system by using a highly integrated system-on-chip (SoC) for faster setup time, improved qubit performance, and efficient scaling to larger qubit counts required for quantum computing to solve practical, real-world applications. The research paper includes the following key technical details:
- Scalability: The integrated SoC design, implemented using the company's 22-nm FFL (FinFET Low Power) CMOS technology, integrates four radio frequency (RF) channels into a single device. Each channel is able to control up to 32 qubits leveraging "frequency multiplexing" – a technique that divides the total bandwidth available into a series of non-overlapping frequency bands, each of which is 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.
- Fidelity: Increases in qubit count 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, the company optimized 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 various frequencies leveraged with Horse Ridge can be "tuned" with high levels of precision, enabling the quantum system to