Covert Entanglement Generation over Bosonic Channels

We explore covert entanglement generation over the lossy thermal-noise bosonic channel, which is a quantum-mechanical model of many practical settings, including optical, microwave, and radio-frequency (RF) channels. Covert communication ensures that an adversary is unable to detect the presence of transmissions, which are concealed in channel noise. We show that a $\textit{square root law}$ (SRL) for covert entanglement generation similar to that for classical: $L_{\rm EG}\sqrt{n}$ entangled bits (ebits) can be generated covertly and reliably over $n$ uses of a bosonic channel. We report a single-letter expression for optimal $L_{\rm EG}$ as well as an achievable method. We additionally analyze the performance of covert entanglement generation using single- and dual-rail photonic qubits, which may be more practical for physical implementation.

@article{anderson2025_2506.09474,
  title={ Covert Entanglement Generation over Bosonic Channels },
  author={ Evan J. D. Anderson and Michael S. Bullock and Ohad Kimelfeld and Christopher K. Eyre and Filip Rozpędek and Uzi Pereg and Boulat A. Bash },
  journal={arXiv preprint arXiv:2506.09474},
  year={ 2025 }
}