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A maximum entangled atomic system consists of 2-two level atoms interacts locally with their own dissipative cavity, is discussed. We show that, the amount of the survival entanglement of the atomic system decays as the detuning parameter increases or the coupling constant decreases. A theoretical teleportation is suggest to teleport a state of one cavity initially prepared in a superposition coherent state to the second cavity is discussed, by using the atomic system as a channel. It is shown that, the efficiency of the suggested teleportation may be improved by increasing the detuning parameter or decreasing the coupling constant between the atomic systems and the cavities.

In this paper, we study the Big Data security based on quantum information theory. In fact, we discuss the opportunities offered by quantum Key distribution (QKD) protocols and quantum algorithms to increase the security level of Big data. In this respect, we used the BB84 protocol to transfer the sent qubits via a quantum channel and Grover’s algorithm to search in NoSql databases in quantum environment. In order to analyze the effectiveness of quantum information theory on big data, we compare the obtained results with those of classical approaches

The Markovianity/non-Markovianity of two different systems are discussed by means of the quantum speed limit time and quantum Fisher information. The first system is described by a central mass particle interacts locally with its surrounding particles, while the second and third models consist of a single qubit interacts with a non-detuning Lorentzian cavity and with a thermal reservoir, respectively. For the first model, the large distance between the central particle and the surrounding particles is guaranty for a fixed quantum speed limit, while the driving time plays the central role on the fixed behavior of the quantum speed limit time. Due to the stable behavior of the quantum speed limit time and the quantum Fisher information, the exchange information between the systems and their surrounding is limited. The distance between the central mass particle and its surrounding particle plays the main role on predicating the Markovianity/non-Markovianity. For the second system the driving time is an important parameter that control on the Markovianity/non-Markovianity behavior. Finally the third model proves that non-Markovianity dynamic may increase the speed and the sensitivity of the open system.

We present a secure direct communication scheme via atomic external degrees of freedom. The scheme consists of transmitting the secret message by superposition of atomic center-of-mass momentum states, quantum bit, via atomic scattering in the Bragg regime and Raman-Nath regime, respectively. The information can be coded/decoded during the transmission, without basis reconciliation, privacy amplification, and end of the communication. The security of information against any eavesdropper is ensured by the interference pattern.