Experimental realization of a four-photon seven-qubit graph state for one-way quantum computation

Area of Science:

• Quantum Information Science
• Photonic Quantum Computing
• Entanglement Engineering

Background:

• Photonic graph states are crucial resources for quantum information processing.
• Scaling up entangled states is a key challenge in quantum computing.
• Previous methods limited the size and complexity of photonic graph states.

Purpose of the Study:

• To demonstrate a scalable method for generating large photonic graph states.
• To create a multi-qubit entangled state using path qubit fusion.
• To verify genuine multi-qubit entanglement and its application in quantum algorithms.

Main Methods:

• Proposed and implemented path qubit fusion technique.
• Generated a two-dimensional seven-qubit graph state from two four-qubit states.
• Utilized polarization and path degrees of freedom for qubits.
• Verified genuine seven-qubit entanglement using a witness operator.

Main Results:

• Successfully generated a seven-qubit photonic graph state.
• Confirmed genuine seven-qubit entanglement.
• Demonstrated the Deutsch-Jozsa algorithm using six qubits of the graph state.
• Achieved a success probability greater than 90% for the algorithm.

Conclusions:

• Path qubit fusion is an effective strategy for scaling photonic graph states.
• The generated seven-qubit state is a valuable resource for quantum computation.
• This work paves the way for larger and more complex photonic quantum systems.