Non-perfect propagation of information to noisy environment with self-evolution
Piotr Mironowicz, Paweł Horodecki, Ryszard Horodecki
备注：
Significantly extended (notion of the indicator basis with further analysis added); version accepted in Special Issue of Entropy "Quantum Darwinism and Friends"
We study the non-perfect propagation of information to evolving low-dimensional environment that includes self-evolution as well as noisy initial states and analyze interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast structure formed during the interaction may exhibit non-monotonicity both in the speed of self-dynamics of the environment as well as its mixedness. The former effect is particularly strong, showing that -- considering part of the environment as a measurement apparatus -- an increase of the external magnetic field acting on the environment may turn the very vague measurement into close to ideal. The above effects suggest that quantum objectivity may appear after increasing the dynamics of the environment, although not with respect to the pointer basis, but some other one which we call generalized pointer or indicator basis. Furthermore, it seems also that when the objectivity is poor it may be improved, at least by some amount, by increasing thermal noise. We provide further evidence of that by analyzing the upper bounds on distance to the set of states representing perfect objectivity in the case of a higher number of qubits.
Superadditivity of Zero-Error Capacity in Noisy Classical and Perfect Quantum Channel Pairs
Indian Institute of Technology, Jodhpur（印度理工学院乔德普尔分校）；Department of Physics of Complex Systems, S. N. Bose National Center for Basic Sciences（S.N. 玻色基础科学国家中心复杂物理系）
Experimental demonstration of robust entanglement distribution over reciprocal noisy channels assisted by a counter-propagating classical reference light
Quantum Technology Lab, Dipartimento di Fisica Aldo Pontremoli , Università di Milano（米兰大学阿尔多·蓬特罗莫利物理系量子技术实验室）；Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia（摩德纳和雷焦艾米利亚大学物理、信息和数学科学系）；Centro S3, CNR-Istituto di Nanoscienze（CNR纳米科学研究所S3中心）；INFN, Sezione di Milano（意大利国家核物理研究所米兰分部）
IBM Quantum, IBM T. J. Watson Research Center（IBM量子，IBM托马斯·J·沃森研究中心）；IBM Almaden Research Center（IBM阿尔马登研究中心）；Google Quantum AI（谷歌量子人工智能）；CMC Microsystems（CMC微系统公司）
