Quantum discord in photon added Glauber coherent states of GHZ{\rm GHZ}-type

We investigate the influence of photon excitations on quantum correlations in tripartite Glauber coherent states of Greenberger-Horne-Zeilinger type. The pairwise correlations are measured by means of the entropy-based quantum discord. We also analyze the monogamy property of quantum discord in this class of tripartite states in terms of the strength of Glauber coherent states and the photon excitation order.Comment: 20 page

Pairwise quantum and classical correlations in multi-qubits states via linear relative entropy

The pairwise correlations in a multi-qubit state are quantified through a linear variant of relative entropy. In particular, we derive the explicit expressions of total, quantum and classical bipartite correlations. Two different bi-partioning schemes are considered. We discuss the derivation of closest product, quantum-classical and quantum-classical product states. We also investigate the additivity relation between the various pairwise correlations existing in pure and mixed states. As illustration, some special cases are examined.Comment: 19 pages, To appear in International Journal of Quantum Informatio

A simple analytical expression of quantum Fisher and Skew information and their dynamics under decoherence channels

In statistical estimation theory, it has been shown previously that the Wigner-Yanase skew information is bounded by the quantum Fisher information associated with the phase parameter. Besides, the quantum Cram\'er-Rao inequality is expressed in terms of skew information. Since these two fundamental quantities are based on the concept of quantum uncertainty, we derive here their analytical formulas for arbitrary two-qubit $X$-states using the same analytical procedures. A comparison of these two informational quantifiers for two quasi-Werner states composed of two bipartite superposed coherent states is examined. Moreover, we investigated the decoherence effects on such quantities generated by the phase damping, depolarization and amplitude damping channels. We showed that decoherence strongly influences the initial quantum criteria and these quantities exhibit similar dynamic behaviors. This current work is characterized by the fact that these two concepts play the same role and capture similar properties in quantum estimation protocols

Study of the chemical inhibition of the scaling of large Agadir water

The distribution mains of drinking water of Large Agadir are the seat of chemical scaling. This phenomenon is due primarily to the precipitation of calcium carbonate. The effectiveness of two chemical inhibitors containing phosphorus was quantified on underground water samples of the area of Agadir. The effective concentrations of these two inhibitors were given