Approach to achieve super Standard Quantum Limit with help of observer.

I want to know if one specific structural argument holds. Take a spin-1 system or NV centre ground-state triplet as a three-level observer T in C³, entangle it with N probe qubits. Joint space is C³ ⊗ (C²)^⊗N, dimension 3·2^N. The joint state I prepare is: |Ψ⟩ = (1/√3) Σᵢ |rᵢ⟩_T ⊗ |φᵢ⟩_P... Read more