Atmospheric effects on satellite-to-ground quantum key distribution using coherent states

TL;DR

This paper investigates the feasibility of satellite-to-ground continuous variable quantum key distribution using coherent states, employing numerical atmospheric turbulence simulations validated against experimental data to estimate secure key rates.

Contribution

It introduces a validated numerical simulation approach for atmospheric effects on satellite-to-ground CV-QKD, improving upon existing analytical models and assessing practical key rate limits.

Findings

Numerical simulations align well with experimental data.

Useful key rates are achievable at certain zenith angles.

The approach advances the assessment of real-world satellite CV-QKD feasibility.

Abstract

Satellite-based quantum cryptography has already been demonstrated using discrete variable technology. Nonetheless, there is great interest in using weak coherent pulses to perform quantum key distribution (QKD) in the continuous variable (CV) paradigm. In this work, we study the feasibility of performing coherent-state CV-QKD via the satellite-to-ground channel. We use numerical methods to simulate atmospheric turbulence and compare the results with ground-based experimental data so as to confirm the validity of our approach. We find the results obtained from the numerical simulations agree well with the experimental data and represent an improvement over the state-of-the-art analytical models. Using the simulation results we then derive QKD key rates and find that useful non-zero key rates can be found over a limited range of zenith angles. Determination of QKD key rates using experimentally validated simulations of low-zenith-angle atmospheric channels represents an important step towards proving the feasibility of real-world satellite-to-Earth CV-QKD.