Additivity of quantum communication channel is discussed in terms of Poisson process to show it is additive in probability. Poisson process is shown to be responsible for entanglement which is a rare event.
From Permutation Symmetry to Communication Bounds and Additivity
Perimeter Institute for Theoretical Physics(Perimeter理论物理研究所);University of Waterloo(滑铁卢大学);Institute for Quantum Computing, University of Waterloo(滑铁卢大学量子计算研究所)
Communication rates over quantum channels can be boosted by entanglement, via superadditivity phenomena or entanglement assistance. Superadditivity refers to the capacity improvement from entangling inputs across multiple channel uses. Nevertheless, when unlimited entanglement assistance is available, the entanglement between channel uses becomes unnecessary -- the entanglement-assisted (EA) capacity of a single-sender and single-receiver channel is additive. We generalize the additivity of EA capacity to general multiple-access channels (MACs) for the total communication rate. Furthermore, fo…
We argue that one of the following statements must be true: (a) extensive violations of quantum information theory's additivity conjectures exist or (b) there exists a set of `disentangled' black hole microstates that can account for the entire Bekenstein-Hawking entropy, up to at most a subleading $O(1)$ correction. Possibility (a) would be a significant result in quantum communication theory, demonstrating that entanglement can enhance the ability to transmit information much more than has currently been established. Option (b) would provide new insight into the microphysics of black holes. …
Machine learning techniques are increasingly being used in fundamental research to solve various challenging problems. Here we explore one such technique to address an important problem in quantum communication scenario. While transferring quantum information through a noisy quantum channel, the utility of the channel is characterized by its quantum capacity. Quantum channels, however, display an intriguing property called super-additivity of coherent information. This makes the calculation of quantum capacity a hard computational problem involving optimization over an exponentially increasing…
Additivity violation of minimum output entropy, which shows non-classical properties in quantum communication, had been proved in most cases for random quantum channels defined by Haar-distributed unitary matrices. In this paper, we investigate random completely positive maps made of Gaussian Unitary Ensembles and Ginibre Ensembles regarding this matter. Using semi-circular systems and circular systems of free probability, we not only show the multiplicativity violation of maximum output norms in the asymptotic regimes but also prove the additivity violation via Haagerup inequality for a new c…
有没有一个有意义的量子通信对应物?我们认为,在接收器和环境之间对称分布量子信息的量子侧信道是纠缠蒸馏和量子纠错中公共量子通信概念的一个很好的候选者。这种联系部分是由[Brandão and Oppenheim,arXiv:1004.3328]激发的,其中发现如果发送方希望使用共享量子态作为密钥通过不安全的量子信道向接收方传递秘密消息,则不安全的量子信道仅用于模拟量子侧信道,并且总是可以由其替换而不改变最佳速率。在这里,我们进一步表明,在完全类似于公共经典通信的作用,由一个辅助方通道使相等的可压缩纠缠,最近引入的相互独立性,和后者的推广,量化的程度,其中一方可以执行量子隐私放大。对称侧信道和密切相关的擦除信道最近被用来提供量子信道容量的超激活的例子。我们的研究结果提供了新的见解,这种非加性的信道容量及其与量子隐私的关系。特别是,我们表明,单副本超激活协议与擦除通道,其中包括所有的例子,非加性的量子容量发现的日期,可以被理解为相互独立到可压缩纠缠的转换。
On super additivity of Fisher information in fully Gaussian metrology
Basque Center for Applied Mathematics (BCAM)(巴斯克应用数学中心);University of the Basque Country UPV/EHU(巴斯克大学);Vienna Center for Quantum Science and Technology (VCQ)(维也纳量子科学与技术中心);TU Wien(维也纳工业大学);IKERBASQUE, Basque Foundation for Science(伊卡巴斯基克,巴斯克科学基金会)
Experimental observation of entropic-singularity-induced nonadditive quantum communication in a qutrit platypus channel
University of Science and Technology of China(中国科学技术大学);CAS Center for Excellence in Quantum Information and Quantum Physics(中国科学院量子信息与量子物理前沿卓越中心);Hefei National Laboratory(合肥国家实验室)
Quantum communication is an important branch of quantum information science, promising unconditional security to classical communication and providing the building block of a future large-scale quantum network. Noise in realistic quantum communication channels imposes fundamental limits on the communication rates of various quantum communication tasks. It is therefore crucial to identify or bound the quantum capacities of a quantum channel. Here, we consider Gaussian channels that model energy loss and thermal noise errors in realistic optical and microwave communication channels and study the…
量子不和谐的积极性被证明是等价的强次加性的冯-努曼熵。这导致了量子信息理论的母协议[A.阿贝耶辛哈岛Devetak,P. Hayden,and A. Winter,Proc. R. Soc. A 465,2537,(2009)]和量子不和谐。我们利用这一点表明,量子不和谐是一个衡量一致性的母亲协议的性能。由于母亲协议是一个统一的一类重要的问题(那些是二分的,单向的和无记忆的),我们表明量子不和谐是在这些协议的一致性的措施。我们的工作推广了早先根据量子态合并[V. Madhok和A. Datta,Phys.Rev.A83,032323,(2011)]。
International Centre for Theory of Quantum Technologies, University of Gdańsk(格但斯克大学量子技术理论国际中心);Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas(坎皮纳斯州立大学格列布·瓦塔金物理研究所);Division of Quantum Optics and Information, Institute of Theoretical Physics and Astrophysics, Faculty of Mathematics, Physics and Informatics, University of Gdańsk(格但斯克大学数学、物理与信息学院理论物理与天体物理研究所量子光学与信息分部)