Attainability of the Holevo-Cramér-Rao bound for two-qubit 3D magnetometry

Jamie Friel, Pantita Palittapongarnpim, Francesco Albarelli +1

We study quantum-limited 3D magnetometry using two qubits. Two qubits form the smallest multi-qubit system for 3D magnetometry, the simultaneous estimation of three phases, as it i…