Reply to Comments on 'On Far-Field Quantum States in Optical Communication'

Carl W. Helstrom

The nature of the conversion of a pure nonclassical transmitted quantum state into a mixed classical state at a remote receiver is discussed under assmnptions appropriate to a free-space optical communication system, with particular reference to a correspondence^{1}containing misconceptions about a paper of the author's [1].

Laura M. Morato

Fu‐Guo Deng, Gui Lu Long

We reply to the preceding comment which focused on whether there exists a quantum privacy amplification technique for purifying the unknown single-photon states transmitted. In this Reply, we will show that quantum privacy amplification is principally possible, and a specific scheme for direct communication protocol based on single photons has been constructed and will be published elsewhere. Then the secure direct quantum communication is secure against the attack strategy in the preceeding comment by using quantum privacy amplification directly.

Konrad Banaszek

C. Bendjaballah, Osamu Hirota, Serge Reynaud

Dario Ferraro, Michele Campisi, Gian Marcello Andolina +2 more

In this short communication we reply to the comment by Xu and Li (arXiv:2411.04132) on our first work on Dicke quantum batteries (Phys. Rev. Lett. 120, 117702 (2018)).