Random quantum channels I: graphical calculus and the Bell state phenomenon

This paper is the first of a series where we study quantum channels from the random matrix point of view. We develop a graphical tool that allows us to compute the expected moments of the output of a random quantum channel. As an application, we study variations of random matrix models introduced by Hayden \cite{hayden}, and show that their eigenvalues converge almost surely. In particular we obtain for some models sharp improvements on the value of the largest eigenvalue, and this is shown in a further work to have new applications to minimal output entropy inequalities.Comment: Several typos were correcte

Inventory and Assessment of Cultural Resources Above the 1,551.5-Foot Contour Line, Stacy Reservoir Recreation Areas, Concho, Coleman, and Runnels Counties, Texas

In August and September 1986, personnel from Prewitt and Associates, Inc. conducted an inventory and assessment of cultural resources in five recreational area tracts above the conservation pool elevation of the proposed Stacy Reservoir in Concho, Coleman. and Runnels counties, Texas. These investigations were sponsored by the Colorado River Municipal Water District in compliance with federal requirements for a construction permit from the Corps of Engineers. Approximately 1,690 acres were surveyed. and five previously unrecorded sites were discovered and documented. Cairn feature sites 41CC213 and 41CC237 are deemed potentially significant and should be preserved or investigated to determine their significance if preservation cannot be assured. In the course of the survey. 16 previously recorded sites were encountered and. in the case of 5 of these sites. adjustments were made in their boundaries. Concurrent with the survey. 11 localities and 34 sites within the previously surveyed conservation pool area were revisited. A preliminary examination of the geologic context of these sites was conducted which resulted in recognition of important geoarcheological data potential for sites in the alluviated valleys of the project area

Nonlinearity of vacuum reggeons and exclusive diffractive production of vector mesons at HERA

The processes of exclusive photo- and electroproduction of vector mesons $\rho^0$(770), $\phi$(1020) and $J/\psi$(3096) at collision energies $30 GeV<W<300 GeV$ and transferred momenta squared $0<-t<2 GeV^2$ are considered in the framework of a phenomenological Regge-eikonal scheme with nonlinear Regge trajectories in which their QCD asymptotic behavior is taken into account explicitly. By comparison of available experimental data from ZEUS and H1 Collaborations with the model predictions it is demonstrated that corresponding angular distributions and integrated cross-sections in the above-mentioned kinematical range can be quantitatively described with use of two $C$-even vacuum Regge trajectories. These are the "soft" pomeron dominating the high energy reactions without a hard scale and the "hard" pomeron giving an essential contribution to photo- and electroproduction of heavy vector mesons and deeply virtual electroproduction of light vector mesons.Comment: 25 pages, 12 figure

Multiplexed Memory-Insensitive Quantum Repeaters

Long-distance quantum communication via distant pairs of entangled quantum bits (qubits) is the first step towards more secure message transmission and distributed quantum computing. To date, the most promising proposals require quantum repeaters to mitigate the exponential decrease in communication rate due to optical fiber losses. However, these are exquisitely sensitive to the lifetimes of their memory elements. We propose a multiplexing of quantum nodes that should enable the construction of quantum networks that are largely insensitive to the coherence times of the quantum memory elements.Comment: 5 pages, 4 figures. Accepted for publication in PR

Gravireggeons and transplanckian scattering in models with one extra dimension

The inelastic scattering of the brane fields induced by $t$-channel gravireggeons exchanges in the RS model with a small curvature $\kappa$ is considered, and the imaginary part of the eikonal is analytically calculated. It is demonstrated that the results can be obtained from the corresponding formulae previously derived in the ADD model with one extra dimension of the size $R_c$ by formal replacement $R_c \to (\pi \kappa)^{-1}$. The inelastic cross section for the scattering of ultra-high neutrino off the nucleon is numerically estimated for the case $\kappa \ll \bar{M}_5 \sim 1$ TeV, where $\bar{M}_5$ is a reduced Planck scale in five warped dimensions.Comment: 17 pages, LaTeX2e, 3 eps figure

A concept for a fuel efficient flight planning aid for general aviation

A core equation for estimation of fuel burn from path profile data was developed. This equation was used as a necessary ingredient in a dynamic program to define a fuel efficient flight path. The resultant algorithm is oriented toward use by general aviation. The pilot provides a description of the desired ground track, standard aircraft parameters, and weather at selected waypoints. The algorithm then derives the fuel efficient altitudes and velocities at the waypoints

Cosmological models with flat spatial geometry

The imposition of symmetries or special geometric properties on submanifolds is less restrictive than to impose them in the full space-time. Starting from this idea, in this paper we study irrotational dust cosmological models in which the geometry of the hypersurfaces generated by the fluid velocity is flat, which supposes a relaxation of the restrictions imposed by the Cosmological Principle. The method of study combines covariant and tetrad methods that exploits the geometrical and physical properties of these models. This procedure will allow us to determine all the space-times within this class as well as to study their properties. Some important consequences and applications of this study are also discussed.Comment: 12 pages, LaTeX2e, IOP style. To appear in Classical and Quantum Gravit

Surface pressure data for a supersonic-cruise airplane configuration at Mach numbers of 2.30, 2.96, 3.30

The tabulated results of surface pressure tests conducted on the wing and fuselage of an airplane model in the Langley Unitary Plan wind tunnel are presented without analysis. The model tested was that of a supersonic-cruise airplane with a highly swept arrow-wing planform, two engine nacelles mounted beneath the wing, and outboard vertical tails. Data were obtained at Mach numbers of 2.30, 2.96, and 3.30 for angles of attack from -4 deg to 12 deg. The Reynolds number for these tests was 6,560,000 per meter