Entanglement detection in a coupled atom-field system via quantum Fisher information

Year: 2017

Authors: Mirkhalaf SS., Smerzi A.

Autors Affiliation: ‎INO CNR, QSTAR, Largo Enrico Fermi 2, I-50125 Florence, Italy;‎ LENS, Largo Enrico Fermi 2, I-50125 Florence, Italy

Abstract: We consider a system of finite number of particles collectively interacting with a single-mode coherent field inside a cavity. Depending on the strength of the initial field compared to the number of atoms, we consider three regimes of weak-, intermediate-, and strong-field interaction. The dynamics of multiparticle entanglement detected by quantum Fisher information and spin squeezing are studied in each regime. It is seen that in the weak- field regime, spin squeezing and quantum Fisher information coincide. However, by increasing the initial field population toward the strong-field regime, quantum Fisher information is more effective in detecting entanglement compared to spin squeezing. In addition, in the two-atom system, we also study concurrence. In this case, the quantum Fisher information as a function of time is in good agreement with concurrence in predicting entanglement peaks.

Journal/Review: PHYSICAL REVIEW A

Volume: 95 (2)      Pages from: 022302-1  to: 022302-10

KeyWords: PHASE-TRANSITION; DICKE-MODEL; RADIATION-FIELD; LIMIT; CAVITY; STATES; GENERATION; LIGHT
DOI: 10.1103/PhysRevA.95.022302

Citations: 7
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