Strategies for choosing path-entangled number states for optimal robust quantum-optical metrology in the presence of loss
Kebei Jiang, Chase Brignac, Yi Weng, Moochan B. Kim, Hwang Lee, Jonathan P. Dowling · Physical Review A · 2012
To acquire the best path-entangled photon Fock states for robust quantum-optical metrology with parity detection, we calculate phase information from a lossy interferometer by using twin entangled Fock states. We show that $(\text{a})$ when loss is less than 50$%$ twin entangled Fock states with large photon number difference give higher visibility, while when loss is higher than 50$%$, the ones with less photon number difference give higher visibility; and $(\text{b})$ twin entangled Fock states with large photon number difference give sub--shot-noise limit sensitivity for phase detection in a lossy environment. This result provides a reference on what particular path-entangled Fock states are useful for real world metrology applications.