Chinese Chip built a 16-qubit state on a single chip

Guizhen Chip Technology and the Ren Xifeng group of China have generated a 16-qubit GHZ state on a single chip, establishing the largest on-chip multi-qubit entangled state reported to date. The team verified that ten of these sixteen qubits were genuinely entangled using entanglement-witness measurements, demonstrating a high degree of control over the quantum system. This result marks a key step for measurement-based optical quantum computing, addressing challenges with multi-photon sources and enabling scalable hardware; the team achieved an average identification probability of 0.987 in a Grover search using this on-chip system.

On-Chip GHZ and Cluster State Generation with Sixteen Qubits

The achievement bypasses a significant hurdle in photonic quantum computing: the difficulty of creating sources for multiple photons and building reliable two-photon gates. Instead, the team employed measurement-based quantum computing, or MBQC, relying on single-qubit measurements performed on a pre-prepared entangled state to drive computation. This approach leverages high-dimensional encoding, where each photon carries multiple qubits through its path degree of freedom, then routes these through a four-layer programmable measurement module.

The architecture transforms a complex multi-photon preparation problem into a more manageable extension of single-photon dimensions combined with layered measurements, making resource-state preparation more deterministic and simplifying the optical hardware required. The research team notes that “MBQC’s wider relevance is that it is the cleanest known route to fault-tolerant, general-purpose quantum computing,” highlighting the potential for scalability.

As a demonstration of the system’s capabilities, the researchers implemented Grover’s search algorithm using a four-qubit cluster state, achieving an average identification probability of 0.987. This level of entanglement is crucial for performing complex quantum calculations and represents a significant step toward practical quantum algorithms. Guizhen Chip’s work positions the company as the first in China to demonstrate on-chip construction of scalable graph states for photonic quantum computing.

The company views this result not as a finished, fully functional quantum computer, but as a key building block for future development. The team anticipates that this technology will allow scaling photonic quantum hardware to the million-qubit range, potentially through architectures like fusion-based quantum computing, which inherits MBQC’s properties and offers even higher fault-tolerance thresholds. The next crucial step, according to the researchers, will be a measured demonstration of fault-tolerant logical qubits under realistic noise conditions, a challenge that is now driving competition within the global quantum computing community.