Kounis Syndrome Associated With Selective Anaphylaxis to Cefazolin.

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Neutral heavy lepton production at next high energy e+e−e^+e^- linear colliders

The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process $e^+e^- \longrightarrow {\nu} e^{\pm} W^{\mp}$ is calculated including on-shell and off-shell heavy neutrino effects. We present a detailed study of cross sections and distributions that shows a clear separation between the signal and standard model contributions, even after including hadronization effects.Comment: 4 pages including 15 figures, 1 table. RevTex. Accepted in Physical Review

High magnetic field induced charge density wave states in a quasi-one dimensional organic conductor

We have measured the high field magnetoresistence and magnetization of quasi-one- dimensional (Q1D) organic conductor (Per)2Pt(mnt)2 (where Per = perylene and mnt = maleonitriledithiolate), which has a charge density wave (CDW) ground state at zero magnetic field below 8 K. We find that the CDW ground state is suppressed with moderate magnetic fields of order 20 T, as expected from a mean field theory treatment of Pauli effects[W. Dieterich and P. Fulde, Z. Physik 265, 239 - 243 (1973)]. At higher magnetic fields, a new, density wave state with sub-phases is observed in the range 20 to 50 T, which is reminiscent of the cascade of field induced, quantized, spin density wave phases (FISDW) observed in the Bechgaard salts. The new density wave state, which we tenatively identify as a field induced charge density wave state (FICDW), is re-entrant to a low resistance state at even higher fields, of order 50 T and above. Unlike the FISDW ground state, the FICDW state is only weakly orbital, and appears for all directions of magnetic field. Our findings are substantiated by electrical resistivity, magnetization, thermoelectric, and Hall measurements. We discuss our results in light of theoretical work involving magnetic field dependent Q1D CDW ground states in high magnetic fields [D. Zanchi, A. Bjelis, and G. Montambaux, Phys. Rev. B 53, (1996)1240; A. Lebed, JETP Lett. 78,138(2003)].Comment: 16 pages, 5 figure

Decoherence of Semiclassical Wigner Functions

The Lindblad equation governs general markovian evolution of the density operator in an open quantum system. An expression for the rate of change of the Wigner function as a sum of integrals is one of the forms of the Weyl representation for this equation. The semiclassical description of the Wigner function in terms of chords, each with its classically defined amplitude and phase, is thus inserted in the integrals, which leads to an explicit differential equation for the Wigner function. All the Lindblad operators are assumed to be represented by smooth phase space functions corresponding to classical variables. In the case that these are real, representing hermitian operators, the semiclassical Lindblad equation can be integrated. There results a simple extension of the unitary evolution of the semiclassical Wigner function, which does not affect the phase of each chord contribution, while dampening its amplitude. This decreases exponentially, as governed by the time integral of the square difference of the Lindblad functions along the classical trajectories of both tips of each chord. The decay of the amplitudes is shown to imply diffusion in energy for initial states that are nearly pure. Projecting the Wigner function onto an orthogonal position or momentum basis, the dampening of long chords emerges as the exponential decay of off-diagonal elements of the density matrix.Comment: 23 pg, 2 fi

Spin-glass behaviour on random lattices

The ground-state phase diagram of an Ising spin-glass model on a random graph with an arbitrary fraction $w$ of ferromagnetic interactions is analysed in the presence of an external field. Using the replica method, and performing an analysis of stability of the replica-symmetric solution, it is shown that $w=1/2$, correponding to an unbiased spin glass, is a singular point in the phase diagram, separating a region with a spin-glass phase ($w<1/2$) from a region with spin-glass, ferromagnetic, mixed, and paramagnetic phases ($w>1/2$)

Duality between quantum and classical dynamics for integrable billiards

We establish a duality between the quantum wave vector spectrum and the eigenmodes of the classical Liouvillian dynamics for integrable billiards. Signatures of the classical eigenmodes appear as peaks in the correlation function of the quantum wave vector spectrum. A semiclassical derivation and numerical calculations are presented in support of the results. These classical eigenmodes can be observed in physical experiments through the auto-correlation of the transmission coefficient of waves in quantum billiards. Exact classical trace formulas of the resolvent are derived for the rectangle, equilateral triangle, and circle billiards. We also establish a correspondence between the classical periodic orbit length spectrum and the quantum spectrum for integrable polygonal billiards.Comment: 12 pages, 4 figure