Experimental Demonstration of Post-Selection based Continuous Variable Quantum Key Distribution in the Presence of Gaussian Noise

TL;DR

This paper demonstrates experimentally that a post-selection based continuous variable quantum key distribution protocol remains secure against Gaussian attacks even with excess Gaussian noise, supported by a new theoretical framework and quantitative key rate analysis.

Contribution

The paper introduces a theoretical framework for post-selection CV-QKD considering Gaussian noise and experimentally verifies its security against Gaussian attacks.

Findings

Post-selection scheme remains secure with excess Gaussian noise.

Derived explicit secret key rate expressions.

Experimental validation of security against Gaussian attacks.

Abstract

In realistic continuous variable quantum key distribution protocols, an eavesdropper may exploit the additional Gaussian noise generated during transmission to mask her presence. We present a theoretical framework for a post-selection based protocol which explicitly takes into account excess Gaussian noise. We derive a quantitative expression of the secret key rates based on the Levitin and Holevo bounds. We experimentally demonstrate that the post-selection based scheme is still secure against both individual and collective Gaussian attacks in the presence of this excess noise.