Eur. Phys. J. D (2012) 66: 69
https://doi.org/10.1140/epjd/e2012-20576-8

Regular Article

Quantum Fisher information for a single qubit system

¹ Mathematics Department, Faculty of Science, Sohag University, 82524 Sohag, Egypt
² Abdus Salam International Centre of Theoretical Physics, ICTP, Trieste, Italy
³ Laboratoire de Physique Théorique, Faculté des Sciences, Avenue Ibn Battouta, 1014-Agdal, Rabat, Morocco
⁴ Mathematics Department, Faculty of Science, Al-Azhar University, Naser City 11884 Cairo, Egypt

^a e-mail: mabdelk@ictp.it
^b e-mail: kberrada@ictp.it

Received: 6 October 2011
Received in final form: 13 January 2012
Published online: 27 March 2012

Abstract

The Fisher information is used for quantum state estimation and considered as a physical resource associated with various quantities. The concept of Fisher information in terms of the atomic density operator is introduced. We give the correlation between the Fisher information and quantum entanglement during the time evolution for a trapped ion in laser field. The effect of the initial state setting on the classical Fisher information and quantum Fisher information is examined. The results show that the Fisher information is efficacious tool to study single qubit dynamics as an indicator of entanglement under certain conditions. Our observations may have important implications in exploiting this quantity in quantum information processing and transmission.