A Fundamental Inequality for Lower-bounding the Error Probability for Classical and Quantum Multiple Access Channels and Its Applications

In the study of the capacity problem for multiple access channels (MACs), a lower bound on the error probability obtained by Han plays a crucial role in the converse parts of several kinds of channel coding theorems in the information-spectrum framework. Recently, Yagi and Oohama showed a tighter bound than the Han bound by means of Polyanskiy's converse. In this paper, we give a new bound which generalizes and strengthens the Yagi-Oohama bound, and demonstrate that the bound plays a fundamental role in deriving extensions of several known bounds. In particular, the Yagi-Oohama bound is generalized to two different directions; i.e, to general input distributions and to general encoders. In addition we extend these bounds to the quantum MACs and apply them to the converse problems for several information-spectrum settings.Comment: under submissio

A Simple Optimum-Time FSSP Algorithm for Multi-Dimensional Cellular Automata

The firing squad synchronization problem (FSSP) on cellular automata has been studied extensively for more than forty years, and a rich variety of synchronization algorithms have been proposed for not only one-dimensional arrays but two-dimensional arrays. In the present paper, we propose a simple recursive-halving based optimum-time synchronization algorithm that can synchronize any rectangle arrays of size m*n with a general at one corner in m+n+max(m, n)-3 steps. The algorithm is a natural expansion of the well-known FSSP algorithm proposed by Balzer [1967], Gerken [1987], and Waksman [1966] and it can be easily expanded to three-dimensional arrays, even to multi-dimensional arrays with a general at any position of the array.Comment: In Proceedings AUTOMATA&JAC 2012, arXiv:1208.249

A Design Study of A Magnetron Injection Gun for A Gyrotron Oscillator

A magnetron injection gun has been designed for an X-band gyrotron oscillator. The design is based on two-dimensional numerical analyses of the equi-potential surfaces and the electron trajectories. The gun can produce a helical beam of electrons with large perpendicular velocities to the magnetic field. The positional velocity spread of the emitting electrons remains within 12% just before injection into an open resonator. The variation of the velocities along the trajectory is studied and compared with that predicted by the adiabatic approximation. The approximation may yield an appreciable deviation due to the neglect of the inward drift of electrons. Typical parameters of the designed electron gun are presented

Quark recombination model for polarizations in inclusive hyperon productions at high energy

We investigate the transverse polarization of hyperons produced by the photon induced reactions using the quark recombination model. This model reproduces polarizations of hadrons produced by the hadron-hadron collisions and accounts for the origin of the empirical rule by DeGrand and Miettinen. We find significant polarizations in the hyperon photoproduction by applying this model to the \gamma N \ra \Lam $(\Sigma^{0}) + X$ reaction.Comment: Latex, 6 page with 6 figures, to be published in proceedings of APCTP Workshop on "Strangeness Nuclear Physics", Feb. 19-22, Seoul, Kore

D6 Family Symmetry and Cold Dark Matter at LHC

We consider a non-supersymmetric extension of the standard model with a family symmetry based on D6 Z2 Z2, where one of Z2's is exactly conserved. This Z2 forbids the tree-level neutrino masses and simultaneously ensures the stability of cold dark matter candidates. From the assumption that cold dark matter is fermionic we can single out the D6 singlet right-handed neutrino as the best cold dark mater candidate. We find that an inert charged Higgs with a mass between 300 and 750 GeV decays mostly into an electron (or a positron) with a large missing energy, where the missing energy is carried away by the cold dark matter candidate. This will be a clean signal at LHC.Comment: 20 pages, 7 figure