Steganographic entanglement sharing
Phys. Rev. A 112, 022604 – Published 5 August, 2025
DOI: https://doi.org/10.1103/kxpv-46v3
Abstract
In a previous work [Avritzer and Brun, Phys. Rev. A 109, 032401 (2024)] we discussed a theoretical grounding for classical steganography using quantum Fock and coherent states in an optical channel, building on previous work by Wu et al. [Opt. Express 14, 3738 (2006); Opt. Express 21, 2065 (2013)]. In that work, we discussed protocols that disguise communications to mimic the thermal state of a harmonic oscillator. In this work we extend this to transmission of quantum information and demonstrate the utility of steganographic entanglement sharing in practical contexts like nonclassical state teleportation. We show that non-Gaussian entangled resources can be transmitted covertly while mimicking a Gaussian thermal state and still retain sufficient entanglement to violate a qubit Bell inequality, even with an eavesdropper present. We also examine the performance of other quantum protocols that utilize entanglement, such as dense coding and teleportation of unentangled but nonclassical states, to determine the effectiveness of the steganographic entanglement sharing under a variety of active and passive eavesdropper conditions.
