Scientists unveil world's first quantum computer built with regular silicon chips

A U.K. startup has created the world's first silicon-based quantum computer manufactured using the same transistor technology found in nearly all modern digital electronics.

The machine is built using the complementary metal-oxide-semiconductor (CMOS) chip fabrication process — the same used to create the chips for devices like smartphones, laptops and digital cameras.

CMOS technology is so widely used because it produces chips that don't draw power when idle. Its integration in a quantum computer paves the way for broad adoption and less expensive manufacturing processes.

Another important element of the machine, built by the company Quantum Motion, is its relatively small footprint. The machine can be housed in just three 19-inch server racks, including the dilution refrigerator and integrated control electronics that manipulate the qubits and produce the extremely low temperatures required to maintain their fragile quantum states.

The system combines a quantum processing unit (QPU) with a user interface and industry-standard control software — the specialized layer that acts as the interpreter between a high-level quantum program (the algorithm) and the physical quantum hardware (the qubits), such as Qiskit and Cirq — to provide a complete quantum computing platform. It uses spin qubits — a type of qubit that encodes quantum information in the spin (intrinsic angular momentum) of an elementary particle, most commonly a single electron.

It's also highly scalable, Quantum Motion representatives said Sept. 15 in a statement. The QPU itself is based on tile architecture — a modular design approach where a processor or a system-on-a-chip (SoC) is built from smaller, self-contained and specialized units called tiles or chiplets.

The QPU condenses the necessary compute, readout and control elements into a single, dense array that can be deployed repeatedly on a single chip. This means that future iterations of the QPU, the physical hardware where quantum computation happens, can be upgraded to include millions of qubits, representatives said, and the system could allow future versions of the company's QPU to be easily swapped in for the existing processor.

“This is quantum computing’s silicon moment,” said James Palles‑Dimmock, CEO of Quantum Motion. “Today’s announcement demonstrates you can build a robust, functional quantum computer using the world’s most scalable technology, with the ability to be mass-produced.”

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Quantum Motion representatives say that this system is the first step to delivering commercially viable quantum computers within the decade.

The system is currently deployed at the U.K. National Quantum Computing Centre (NQCC) – a national lab for quantum computing, funded primarily through the UK Research and Innovation (UKRI) program. UKRI is a public body that directs research and innovation funding in the U.K.

Quantum Motion's system also represents the first silicon spin‑qubit computer developed under the auspices of NQCC’s Quantum Computing Testbed Programme, an initiative to build seven prototype quantum computers using differing technologies and test their viability.

The computer builds on research undertaken by Quantum Motion in conjunction with University College London (UCL) to create more fault-tolerant quantum systems. That research demonstrated 98% accuracy in two-qubit gates, the fundamental building block of a quantum circuit. That's a world-leading mark in qubits fabricated in natural silicon on a 300mm wafer scale, the same material used in the new computer.

Fault tolerance is critical to quantum computing because qubits are notoriously fragile and error-prone. The instability is due to a property called decoherence.

Superposition (the ability for a qubit to exist in multiple states at once) and entanglement (the ability of two or more qubits to be connected to one another and share the same state across any distance, so that altering one alters the other simultaneously), the keys to quantum computation, are both fragile states that can be destroyed by even the slightest interaction with the environment.

Changes in temperature, electromagnetic interference or other environmental factors can distort or collapse those properties, leading to inaccurate results. That fragility is one of the biggest obstacles to scalable and powerful quantum computing. That's why plenty of quantum computing research is in the area of quantum error correction (QEC).

As part of the SiQEC silicon quantum error correction project, Quantum Motion leverages silicon spin qubits created using standard 300 mm semiconductor manufacturing processes and its error correction research to build fault-tolerant architectures that could scale to the millions of qubits needed for quantum advantage.

The primary edge this kind of manufacturing holds over other processes is the commonality of the silicon manufacturing. Because the facilities, standards and techniques for effectively mass-producing these kinds of chips are already well-established, they can be produced more cheaply, quickly and at a greater scale than other, more specialized components.