Unidimensional continuous-variable quantum key distribution using squeezed states

TL;DR

This paper explores using squeezed states in unidimensional continuous-variable quantum key distribution, showing how squeezing and antisqueezing affect security bounds and practicality in noisy, short-distance channels.

Contribution

It demonstrates that squeezing can expand physicality bounds and improve security in unidimensional CV-QKD, offering a practical approach for low-loss channels.

Findings

Squeezing expands the physicality bounds of the shared entangled state.

Antisqueezing noise limits eavesdropping in noisy channels.

The strategy is effective for short-distance, low-loss channels with direct reconciliation.

Abstract

The possibility of using squeezed states in the recently suggested unidimensional continuous-variable quantum key distribution based on a single quadrature modulation is addressed. It is shown that squeezing of the signal states expands the physicality bounds of the effective entangled state shared between the trusted parties due to the antisqueezing noise in the unmodulated quadrature. Modulation of the antisqueezed quadrature, on the other hand, effectively shrinks the physicality bounds due to the squeezing in the unmodulated quadrature and also provides noise on the reference side of the protocol, thus limiting the possibility of eavesdropping in noisy channels. This strategy is practical for low-loss (i.e., short-distance) channels, especially if direct reconciliation scheme is applied.