Rotonium has demonstrated a quantum computer prototype with four effective qubits housed on a chip measuring just 18 by 4 millimetres, the company says. The machine operates at room temperature, eliminating the need for cryogenic cooling throughout the quantum system, from photon source to detector. This approach encodes quantum information using single photons and their “degrees of freedom,” allowing multiple qubits to be represented within a single photon.

“Quantum computing must not become a technology reserved for a handful of large research centres,” says Roberto Siagri, co-founder and CEO of Rotonium. “What matters is not only how many qubits we can develop, but how usable they really are at the edge. This is what we call Industrial Quantum Utility.”

Photonic Chip Achieves Four Effective Qubits at Room Temperature

The Rotonium processor achieves high qubit density by representing multiple qubits within a single photon, using the quantum properties known as degrees of freedom. This approach contrasts with many existing quantum systems that require a dedicated physical qubit for each unit of quantum information, potentially offering a pathway to scaling computational power without a proportional increase in hardware.

The company’s design uses silicon photonics manufacturing processes, a significant step toward integrating quantum capabilities into existing semiconductor infrastructure. Six patent families, encompassing 25 applications and six granted patents, currently protect this core technology, demonstrating substantial investment in its novelty and long-term viability.

Fabrizio Tamburini, co-founder and Chief Quantum Officer of Rotonium, explains that “Our prototype demonstrates the feasibility of compact photonic circuits and provides the foundation for a progressive increase in computing capacity.” The prototype itself measures 18 by 4 millimetres, a considerable reduction in size compared to many current quantum computing platforms, and operates without the need for cryogenic cooling. Eliminating cryogenics simplifies system integration and reduces energy consumption, addressing key barriers to wider adoption of quantum technologies.

Rotonium’s focus extends beyond simply building qubits. The company is targeting “Industrial Quantum Utility” by developing compact quantum accelerators for applications like robotics and autonomous vehicles.