Numerical simulations of atmospheric quantum channels

TL;DR

This paper uses numerical simulations to analyze atmospheric quantum channels, comparing various models for transmittance distribution and introducing a new empirical Beta distribution model for better accuracy.

Contribution

It provides a comprehensive numerical approach to model atmospheric turbulence effects on quantum communication and introduces an empirical Beta distribution model for transmittance.

Findings

The applicability of analytical models depends on receiver aperture size.

The Beta distribution model fits a wide range of channel parameters.

Numerical simulations reveal scenarios where analytical models fail.

Abstract

Atmospheric turbulence is one of the lead disturbance factors for free-space quantum communication. The quantum states of light in such channels are affected by fluctuating losses characterized by the probability distribution of transmittance (PDT). We obtain the PDT for different horizontal links via numerical simulations of light transmission through the atmosphere. The results are compared with analytical models: the truncated log-normal distribution, the beam-wandering model, the elliptic-beam approximation, and the model based on the law of total probability. Their applicability is shown to be strongly dependent on the receiver aperture radius. We introduce an empirical model based on the Beta distribution, which is in good agreement with numerical simulations for a wide range of channel parameters. However, there are still scenarios where none of the above analytical models fits the numerically simulated data. The numerical simulation is then used to analyze the transmission of quadrature-squeezed light through free-space channels.