Insider Brief
- Hefei Sizhen Chip Technology and researchers from the University of Science and Technology of China reported an on-chip photonic quantum computing demonstration using programmable silicon photonic chips.
- The team reported generating a 4-photon 16-qubit GHZ state and a single-photon 4-qubit cluster state using a measurement-based quantum computing approach.
- The research explores how high-dimensional photonic encoding and programmable photonic circuits could support scalable quantum computing architectures.
Hefei Sizhen Chip Technology Co., Ltd. and the research group of Professor Ren Xifeng at the Key Laboratory of Quantum Information, University of Science and Technology of China have reported a breakthrough in photonic quantum computing chip technology, Jiwei reported.
Working with a self-developed programmable silicon photonic integrated chip, the team says it has achieved, for the first time, the stable on-chip generation of a 4-photon 16-qubit GHZ state and a single-photon 4-qubit cluster state. The research has been submitted as a preprint to arXiv under the title “On-chip generation of multi-qubit graph states with high-dimensional encoded single photons.”
Technical Approach
In optical quantum computing, multi-photon entangled states are the core resource for implementing quantum algorithms. The source notes that the emission efficiency of multi-photon sources is low and that preparation probability decreases exponentially with the number of photons, making multi-photon entanglement a limited resource.
To address this, the team developed a method for preparing entangled state resources under a measurement-based quantum computing (MBQC) approach. Using the path degrees of freedom of a single photon to perform high-dimensional encoding, the method transforms the problem of preparing complex multi-photon states into high-dimensional expansion, routing, and hierarchical measurement operations on single photons. A four-layer programmable measurement module is used to achieve efficient preparation of multi-qubit graph states and arbitrary single-qubit measurements, as per Jiwei.
Experimental Results
The team successfully prepared a 4-photon 16-qubit GHZ state and verified the genuine entanglement of 10 qubits through the entanglement witnessing method. The source describes this as the largest-scale entangled state demonstrated on an optical quantum chip to date.
In a separate demonstration, the team used single photons to prepare a 4-qubit cluster state and ran the Grover search algorithm on that basis, achieving an average identification probability of 0.987.
About the MBQC Approach
MBQC is described in the source as a universal quantum computing model that uses the preparation of large-scale entangled states as a resource and relies solely on single-qubit measurements to drive computation. Compared to the quantum logic gate circuit model in common use, MBQC shifts computational difficulty from executing logic gate operations at runtime to preparing the initial entangled state.
According to Jiwei, this approach addresses the absence of efficient deterministic two-qubit logic gates in photonic systems, enabling universal computation without deterministic photon-photon interactions. The source also states that MBQC can achieve a larger qubit scale under the same photon resource conditions, reducing hardware complexity. Its derived architecture, fusion-based quantum computing (FBQC), is noted to offer higher fault-tolerance thresholds
Company Statement
Sizhen Chip described itself, in a statement carried by the source, as the first domestic optical quantum computing company to achieve large-scale graph state construction on-chip, adding that the result makes the development of a million-qubit optical quantum computer feasible.
For readers looking to go deeper on the technology and the companies building it, TQI’s guide to photonic quantum technology companies in 2026 covers the full landscap.
