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2024-11-22 2:19

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Conference: Bucharest University Faculty of Physics 2021 Meeting

Section: Theoretical Physics and Applied Mathematics

Title:

Secure quantum teleportation using Gaussian resource states

Authors:

Marina CUZMINSCHI (1,2), Alexei ZUBAREV (3), Aurelian ISAR (1,2)

^*
Affiliation:

1) Horia Hulubei National Institute of Physics and Nuclear Engineering, Romania

2) Faculty of Physics, University of Bucharest, Romania

3) National Institute for Laser, Plasma and Radiation Physics, Romania

E-mail

marina.cuzminschi@gmail.com

Keywords:

Gaussian state, Quantum teleportation, entanglenment, steering

Abstract:

We describe the Markovian dynamics of the fidelity of quantum teleportation and entanglement in a system consisting of two coupled bosonic modes in contact with a thermal environment. The study is done in the framework of the theory of open systems based on completely positive quantum dynamical semigroups. We use the logarithmic negativity as the measure of entanglement in the system. As the initial state is chosen an entangled thermal or vacuum two mode Gaussian state. This state is taken as a resource for the teleportation of a coherent state. Employing the covariance matrix formalism we study the evolution in time of the fidelity of teleportation and of the logarithmic negativity, and their dependence on the temperature of the thermal bath, squeezing between the modes, coupling between the modes, frequencies of the two modes and the average number of thermal photons of the two bosonic modes [1,2]. We find that the squeezed vacuum state is the most beneficial as a resource of teleportation, due to the fact that the fidelity of teleportation decreases with the average number of thermal photons of the two modes. Optimal values of the squeezing and coupling parameters for the teleportation of a pure coherent state are determined. We show that the considered system assures values of fidelity of teleportation larger than the classical limit 1/2, and in some determined cases this fidelity has values even larger than 2/3, necessary for secure teleportation. Another necessary condition for secure teleportation is the two-ways steering, steering being a stronger correlation than entanglement. In the limit of large times, for definite values of coupling between the modes and for low temperatures of the reservoir, the states remain entangled, which is a crucial condition for the realization of the quantum teleportation protocol[3].

References:

[1] Zubarev, Alexei, Marina Cuzminschi, and Aurelian Isar. "Optimal fidelity of teleportation using two-mode gaussian states in a thermal bath as a resource." Romanian Journal of Physics 64 (2019): 108.

[2] Cuzminschi, Marina, Alexei Zubarev, and Aurelian Isar. "Quantum fidelity of two-mode gaussian states in a thermal reservoir." PROCEEDINGS OF THE ROMANIAN ACADEMY SERIES A-MATHEMATICS PHYSICS TECHNICAL SCIENCES INFORMATION SCIENCE 20.3 (2019): 251-258.

[3] Cuzminschi, Marina, and Alexei Zubarev. "Chaotic behavior of a stack of intrinsic Josephson junctions at the transition to branching for overcritical currents." Chinese Journal of Physics 71 (2021): 634-642.

Acknowledgement:

A. Zubarev acknowledges financial support from the Projects 16N/08.02.2019 and EURATOM WPJET1 C. A. Isar acknowledges the financial support received from the Romanian Ministry of Education and Research, through the Project PN 19 06 01 01/2019.