Yes, cloud-based quantum computing can offer a quantum advantage, particularly when quantum circuits capable of generating entangled states are utilized. Entangled qubits can significantly speed up certain computations.

Entanglement witness circuits are specially designed circuits that help certify the presence of entangled qubits using only measurement statistics output by the cloud service. They enable researchers to detect entanglement without needing direct control over qubit allocation.

Researchers using services like IBMQ can allocate specific qubits to their circuits, but in IonQ, they lack this control. This limitation can hinder the ability to compute the output of the entanglement witness function accurately.