Can a silicon chip handle complex quantum states without relying on conventional multi-photon resources? A programmable photonic approach offers another route.
Sizhen Chip Technology and researchers from the University of Science and Technology of China have demonstrated the on-chip generation of multi-qubit photonic quantum states using a programmable silicon photonic integrated chip. The team reported a 4-photon, 16-qubit GHZ state and a single-photon, 4-qubit cluster state using a measurement-based quantum computing approach.
The work addresses a key challenge in photonic quantum computing, where generating large multi-photon entangled states becomes increasingly difficult as the number of photons rises. The reported approach instead uses the path degree of freedom of a single photon to encode multiple qubits, potentially reducing the photon resources required for preparing complex quantum states.
The silicon photonic platform provides programmable routing and measurement functions for manipulating these encoded states. The architecture uses a four-layer programmable measurement module to perform high-dimensional expansion, routing, hierarchical measurements, and arbitrary single-qubit measurements.
In the experiment, the researchers generated a 4-photon 16-qubit GHZ state and verified genuine entanglement across 10 qubits using an entanglement-witnessing method. The team also generated a single-photon 4-qubit cluster state and used it to run a Grover search algorithm, achieving an average identification probability of 0.987.
The approach follows measurement-based quantum computing, where computation is driven by measurements performed on a pre-prepared entangled state rather than by executing a sequence of conventional quantum gates. This can help address limitations associated with deterministic two-qubit interactions between photons.
