Showing papers on "Quantum channel published in 1985"
23 Aug 1985
TL;DR: It is proved that no technology whatsoever, as well as no amount of computing power, could break some of the authors' schemes, as long as some of the most fundamental principles of quantum physics hold true.
Abstract: Although written aboutfifteen years ago, Wiesner’s seminal paper, to which the origin of quantum cryptography must be traced back, did not appear in print until the spring of 1983 [W83]. The first published account of these ideas thus appeard in the proceedings of the second annual CRYPTO conference [BBBW83]. However, the concepts presented there were mostly of theoretical interest, because the technology involved in implementing them wouldhave been far beyond the reach of our current knowledge. In particular, single polarized photons had to be trapped, bounding back and forth between perfectly reflecting mirrors, and perfect efficiency in photon detection was required. To make up for this inconvenience, we could prove that no technology whatsoever, as well as no amount of computing power, could break some of our schemes, as long as some of the most fundamental principles of quantum physics hold true.
126 citations
TL;DR: In this article, the authors briefly review the mathematical formulation of quantum communication theory and construct a physical model of the optical fiber communication process in order to examine the qualitative properties of the communication channel.
Abstract: The communication of information by means of laser is an important technique. Therefore, it is necessary to construct a communication theory (quantum information theory) including quantum effects of laser action. Ohya, one of the authors, has studied the quantum communication channel and constructed a compound state for systematic formulation of the mutual information in quantum systems. In this paper, (1) we briefly review the mathematical formulation of quantum communication theory and (2) construct a physical model of the optical fiber communication process in order to examine the qualitative properties of the communication channel.
36 citations
2 citations
TL;DR: In this article, the problem of selection of preferred basis during passage from quantum to classical systems is treated with the help of a simple example of a 2-state system like the sugar molecule.
Abstract: The problem of selection of preferred basis during passage from quantum to classical systems is treated with the help of a simple example of a 2-state system like the sugar molecule. A simple principle leading to this selection is stated and demonstrated in case of the chosen example. The principle, stated simply is that the preferred basis is the one in which the system environment interaction hamiltonian is diagonal.