Detecting genuine multipartite entanglement (GME) is a state-characterization task that benchmarks coherence and experimental control in quantum systems. Existing GME tests often require joint measurements on many qubits, posing challenges for systems like time-bin encoded qubits and microwave photons from superconducting circuits, where qubit connectivity is limited or measurement noise grows with the number of jointly measured qubits. Here we introduce versatile GME and k-inseparability criteria applicable to any state, which only require measuring O(n2) out of 2n (at most) m-body stabilizers of n-qubit target graph states, with m upper-bounded by twice the graph’s maximum degree. For cluster or ring-graph states, only constant-weight stabilizers are needed. Using semidefinite programming (and sometimes graph-local complementations), we can reduce the number or weight of required stabilizers. Analytical and numerical results show that our criteria are noise-robust and may infer state infidelity from certified k-inseparability in microwave photonic graph states generated under realistic conditions. Certifying multipartite entanglement can benchmark quantum devices. Here, authors introduce versatile tests that can certify genuine multipartite entanglement and k-inseparability using only few-body measurements, enabling noise-robust benchmarking of large photonic and superconducting graph states.

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Nature

Researchers introduce new criteria for detecting genuine multipartite entanglement in quantum systems using only few-body measurements. The method requires measuring O(n²) stabilizers instead of exponentially many, with stabilizer weights bounded by twice the graph's maximum degree. For cluster and ring-graph states, only constant-weight stabilizers are needed. The approach uses semidefinite programming to reduce measurement requirements and demonstrates noise-robust performance on simulated microwave photonic graph states from superconducting circuits, enabling practical benchmarking of large-scale quantum devices where joint measurements are restricted.

Detecting genuine multipartite entanglement in multi-qubit devices with restricted measurements

Certifying GME/ k -inseparability in simulated states

Noise sensitivity of the GME/ k -inseparability criteria