Fundamentals of Quantum Communication through Atmospheric Channels
Final Report Abstract
Elliptic-beam model. The description of atmospheric quantum channels is based on the idea of a step-by-step inclusion of different atmospheric effects into the theory, such as beam wandering and beam deformation. For this purpose we have developed the elliptic-beam model. Additionally to beam wandering, this model incorporates fluctuations of the beam-spot radius and random deformations of the beam profile into an elliptic form. Beam-wandering, beam broadening, and beam deformation result in a fluctuating transmittance through the receiver aperture. The elliptic-beam model can be applied for the consistent description of quantum and classical light propagation in the regimes of weak-to-moderate and strong turbulence. The proposed methodology allows one to analyze many propagation scenarios. Model of quantum atmospheric links based on the law of total probability. The elliptic-beam approximation is a reasonable one for short atmospheric quantum channels. However, the application of the elliptic-beam model may fail for long-distance quantum channels. Indeed, in such cases the transmitted beam profile shows quite complex structures due to speckles and beam brake-ups. To deal with such complex situations, have introduced a model based on the law of total probability. This model is based on the observation that one can separate beam wandering effects from the effects induced by the diffraction in the atmosphere. In our method, beam wandering is separated from beam broadening and deformation effects. We have used the law of total probability from Bayesian statistical analysis to derive the long-distance transmission statistics of light based on these ideas. Satellite-mediated quantum atmospheric links. So far we have developed methods to characterize horizontal communication links under weak-tomoderate and strong turbulence conditions. In such cases, the turbulence is considered to be homogeneous and isotropic. However, global quantum communication is possible by using orbiting satellites as the sources, the receivers, or the transmitters of quantum information. If one or both communication parties are situated on the Earth’ surface, the satellite-mediated communication utilizes the elevated or vertical quantum links. In this case, the turbulent atmosphere cannot be considered as a spatially and temporally homogeneous and isotropic medium. Indeed, the Earth’ atmosphere has a complex stratified structure. Each layer of the atmosphere has a different vertical thickness and turbulence strength. Its complex dynamics is governed by day-time and seasonal variations of meteorological conditions. As presently no detailed theory of satellite-based communication channels exists, we have analized such scenarios in some detail.
Publications
- Atmospheric Quantum Channels with Weak and Strong Turbulence, Phys. Rev. Lett. 117, 090501 (2016)
D. Vasylyev, A.A. Semenov, and W. Vogel
(See online at https://doi.org/10.1103/PhysRevLett.117.090501) - Bell nonlocality in the turbulent atmosphere, Phys. Rev. A 94, 053801 (2016)
M. O. Gumberidze, A. A. Semenov, D. Vasylyev, and W. Vogel
(See online at https://doi.org/10.1103/PhysRevA.94.053801) - Free-space quantum links under diverse weather conditions, Phys. Rev. A 96, 043856 (2017)
D. Vasylyev, A. A. Semenov, W. Vogel, K. Günthner, A. Thurn, Ö. Bayraktar, and Ch. Marquardt
(See online at https://doi.org/10.1103/PhysRevA.96.043856) - Characterization of free-space quantum channels, Proc. SPIE 107710 107710V-1 (2018)
D. Vasylyev, A. A. Semenov, and W. Vogel
(See online at https://doi.org/10.1117/12.2320037) - Nonclassicality and Bell nonlocality in atmospheric links, Proc. SPIE 107710 107710Z-1 (2018)
A. A. Semenov; M. Bohmann; D. Vasylyev; W. Vogel
(See online at https://doi.org/10.1117/12.2319475) - Theory of atmospheric quantum channels based on the law of total probability, Phys. Rev. A 97, 063852 (2018)
D. Vasylyev, W. Vogel, and A. A. Semenov
(See online at https://doi.org/10.1103/PhysRevA.97.063852)
