Generalized fisher information and upper bounds on the differential entropy of independent sums

2016 ◽  
Author(s):  
Jihad Fahs ◽  
Ibrahim Abou-Faycal
Keyword(s):  
Fisher Information ◽  
Upper Bounds ◽  
Differential Entropy ◽  
Generalized Fisher Information

Quantum Fisher information of two superconducting charge qubits under dephasing noisy channel

2018 ◽  
Vol 32 (22) ◽  
pp. 1850245 ◽  
Author(s):  
Hamada Abdel-Hameed ◽  
Nour Zidan ◽  
Nasser Metwally
Keyword(s):  
Mutual Information ◽  
Quantum Cryptography ◽  
Fisher Information ◽  
Quantum Fisher Information ◽  
Upper Bounds ◽  
Noisy Channel ◽  
Information Displays ◽  
Charge Qubits ◽  
Gradual Decay

The Quantum Fisher information (QFI) of a two charged qubits system that interacts locally with a dephasing channel is quantified with respect to the charged qubits’ and the channel’s parameters. The behavior of Fisher information displays different phenomena as; the sudden changes (increasing/decreasing); the gradual decay and freezing of the QFI. It is shown that the QFI of the dephasing parameter decays gradually and vanishes completely as one increases the initial energies of the qubits and their mutual energy. The possibility of estimating the charged qubits’ energies may be maximized at smaller values of the initial dephasing’s parameter. The estimation degree of the mutual information reaches its upper bounds by increasing the initial energies. It is depicted that, by controlling the qubits’ and the channel’s parameters, the QFI may be frozen. We expect that this result may be interesting in the context of quantum encoding and quantum cryptography.

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