Quantum Fisher information of entangled coherent state in the presence of photon losses: exact solution

Autor:	Zhang, Y. M., Li, X. W., Yang, W., Jin, G. R.
Rok vydání:	2013
Předmět:	Quantum Physics Condensed Matter - Quantum Gases Physics - Atomic Physics Physics - Optics
Zdroj:	Physical Review A 88, 043832 (2013)
Druh dokumentu:	Working Paper
DOI:	10.1103/PhysRevA.88.043832
Popis:	We investigate the performance of entangled coherent state for quantum enhanced phase estimation. An exact analytical expression of quantum Fisher information is derived to show the role of photon losses on the ultimate phase sensitivity. We find a transition of the sensitivity from the Heisenberg scaling to the classical scaling due to quantum decoherence of the photon state. This quantum-classical transition is uniquely determined by the number of photons being lost, instead of the number of incident photons or the photon loss rate alone. Our results also reveal that a crossover of the sensitivity between the entangled coherent state and the NOON state can occur even for very small photon loss rate. Comment: 7 page, 3 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1307.7353 Zobrazit plný text záznamu View this record from Arxiv