2020/02/29 by Koji Yamaguchi, Aida Ahmadzadegan, Petar Simidzija +2
Computer Science · Mathematics · Physics and Astronomy · #Geology #Mathematical economics #Mathematics #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Superadditivity #gr-qc #hep-th #quant-ph
paper · pdf · doi:10.1103/physrevd.101.105009
published as Phys. Rev. D 101, 105009 (2020) · 22 pages, 49 figures. Typos have been fixed
arxiv created 2020/05/05 · openalex publication_date 2020/05/14 · arxiv updated 2020/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Given that any communication is communication through quantum fields, we study here the scenario where a sender, Alice, causes information-carrying disturbances in a quantum field. We track the exact spread of these disturbances in space and time by using the technique of quantum information capsules (QIC). We find that the channel capacity between Alice and a receiver, Bob, is enhanced by Bob placing detectors not only inside but in addition also outside the causal future of Alice's encoding operation. Intuitively, this type of superadditivity arises because the field outside the causal future of Alice is entangled with the field inside Alice's causal future. Hence, the quantum noise picked up by Bob's detectors outside Alice's causal future is correlated with the noise of Bob's detectors inside Alice's causal future. In effect, this correlation allows Bob to improve the signal-to-noise ratio of those of his detectors which are in the causal future of Alice. Further, we develop the multimode generalization of the QIC technique. This allows us to extend the analysis to the case where Alice operates multiple localized and optionally entangled emitters. We apply the new techniques to the case where Alice enhances the channel capacity by operating multiple emitters that are suitably lined up and pretimed to generate a quantum shockwave in the field.