Quantum Information and Communication: From Foundations to Applications

Dear Colleagues,

Recent years have been characterized by a tremendous development of quantum information and communication, both in theory and experiment: quantum computers and, recently, quantum stimulators, cryptography, teleportation, and quantum random generators. It is now clear that this great project is essentially more complex than one would have expected at its initial stage and that its realization demands much more effort on the parts of both theoreticians and experimenters. This is a good time to examine and summarize the results, thus far, of various intensive studies and experimentations regarding, both, successes and difficulties. It is the moment to present expectations of the further developments of the field, to formulate further challenges and problems, and to point out any possible, hidden pitfalls for the future.

The quantum information revolution has significantly increased the interest in the foundations of quantum mechanics. This topic is no longer the business of only philosophers and historians of science, but it is now also largely unavoidable to practicing physicists, theoreticians, and even experimenters. While complemented by the more traditional philosophical analysis, foundational studies are now based, much more firmly, on complex theoretical models, advanced mathematics, and numerical simulations that are very closely related to experiments. The intensive development of quantum information and quantum technologies continually generates novel foundational problems. The problem of distinguishing classical and quantum randomness and justification of the use of quantum random generators, which before was merely a philosophic problem, plays a fundamental role in development of quantum technologies, is one example.

Recently, the mathematical formalism of quantum information theory and quantum probability has provided numerous applications outside of physics, in cognitive and social sciences, psychology, decision-making, economics, psychology, finances, and politics.  In such applications, quantum theory is treated operationally as representing contextual probabilistic behavior of systems of any kind. There are plenty of statistical data, collected in the aforementioned domains of science that do not match the laws of classical probability theory (Kolmogorov, 1933), but can be successfully described and modeled in the framework of quantum theory. Such an approach in the use of quantum formalism is certainly quantum-like, even if a system itself need not necessarily be described by quantum physics; it only exhibits some non-classical information-probabilistic features, and has been exhibited in recent decades, in some situations in quantum optics, which were initially thought to absolutely require quantum entanglement, but were understandable in the absence of it as well, with quantum mechanical formalism being the preferred formal framework in any case.

The aim of this Special Issue is to encourage scientists to present original and recent developments, as well as review papers, on quantum information and communications and the related problems of quantum foundations. Quantum information is treated widely enough to even cover applications of its formalism outside of the physics mentioned above.

One of the objectives of this issue is to promote cross-fertilization among scientists working in a wide range of areas of quantum information, communication and foundations, and theory and applications; for example, interrelation of quantum information theory and theory of open quantum systems, Bell’s inequality, its probabilistic structure and especially its role in theory of quantum random generators, statistical analysis of experimental data, foundations of quantum mechanics, entanglement, and quantum-like models in decision making. One question of especially high interest (in the light of recent experiments in labs of A. Zeilinger and P. Kwiat to close the detection efficiency loophole) is the analysis of the trade-off between entanglement and non-purity of states, leading to violations of the Eberhard and Clauser-Horne versions of Bell’s inequality.

Prof. Gregg Jaeger
Prof. Andrei Khrennikov
Guest Editors

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