2,604 research outputs found

    On the area expectation values in area tensor Regge calculus in the Lorentzian domain

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    Wick rotation in area tensor Regge calculus is considered. The heuristical expectation is confirmed that the Lorentzian quantum measure on a spacelike area should coincide with the Euclidean measure at the same argument. The consequence is validity of probabilistic interpretation of the Lorentzian measure as well (on the real, i.e. spacelike areas).Comment: LaTeX, 7 pages, introduction and discussion given in more detail, references adde

    Unified Brane Gravity: Cosmological Dark Matter from Scale Dependent Newton Constant

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    We analyze, within the framework of unified brane gravity, the weak-field perturbations caused by the presence of matter on a 3-brane. Although deviating from the Randall-Sundrum approach, the masslessness of the graviton is still preserved. In particular, the four-dimensional Newton force law is recovered, but serendipitously, the corresponding Newton constant is shown to be necessarily lower than the one which governs FRW cosmology. This has the potential to puzzle out cosmological dark matter. A subsequent conjecture concerning galactic dark matter follows.Comment: 6 pages, to be published in Phys. Rev.

    Degeneracies when T=0 Two Body Interacting Matrix Elements are Set Equal to Zero : Talmi's method of calculating coefficients of fractional parentage to states forbidden by the Pauli principle

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    In a previous work we studied the effects of setting all two body T=0 matrix elements to zero in shell model calculations for 43^{43}Ti (43^{43}Sc) and 44^{44}Ti. The results for 44^{44}Ti were surprisingly good despite the severity of this approximation. In this approximation degeneracies arose in the T=1/2 I=(1/2)1({1/2})^-_1 and (13/2)1({13/2})^-_1 states in 43^{43}Sc and the T=1/2 I=(13/2)2I=({13/2})_2^-, (17/2)1({17/2})^-_1, and (19/2)1({19/2})_1^- in 43^{43}Sc. The T=0 32+3_2^+, 72+7_2^+, 91+9_1^+, and 101+10_1^+ states in 44^{44}Ti were degenerate as well. The degeneracies can be explained by certain 6j symbols and 9j symbols either vanishing or being equal as indeed they are. Previously we used Regge symmetries of 6j symbols to explain these degeneracies. In this work a simpler more physical method is used. This is Talmi's method of calculating coefficients of fractional parentage for identical particles to states which are forbidden by the Pauli principle. This is done for both one particle cfp to handle 6j symbols and two particle cfp to handle 9j symbols. The states can be classified by the dual quantum numbers (Jπ,JνJ_{\pi},J_{\nu})

    Interferon alpha suppresses alphaherpesvirus immediate early protein levels in sensory neurons, leading to the establishment of a latent infection

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    Alphaherpesviruses are a subfamily of the herpesviruses containing closely related human and animal pathogens, including human herpes simplex virus (HSV-1) and porcine pseudorabies virus (PRV)

    Quantum scale invariance on the lattice

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    We propose a scheme leading to a non-perturbative definition of lattice field theories which are scale-invariant on the quantum level. A key idea of the construction is the replacement of the lattice spacing by a propagating dynamical field -- the dilaton. We describe how to select non-perturbatively the phenomenologically viable theories where the scale invariance is broken spontaneously. Relation to gravity is also discussed.Comment: 5 page

    Indications for Criticality at Zero Curvature in a 4d Regge Model of Euclidean Quantum Gravity

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    We re-examine the approach to four-dimensional Euclidean quantum gravity based on the Regge calculus. A cut-off on the link lengths is introduced and consequently the gravitational coupling and the cosmological constant become independent parameters. We determine the zero curvature, =0 =0, line in the coupling constant plane by numerical simulations. When crossing this line we find a strong, probably first order, phase transition line with indications of a second order endpoint. Beyond the endpoint the transition through the =0 =0 line appears to be a crossover. Previous investigations, using the Regge or the Dynamical Triangulation approach, dealt with a limit in which the first order transition prevails.Comment: Contribution to the lattice 2003 Tsukuba symposiu

    Measure dependence of 2D simplicial quantum gravity

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    We study pure 2D Euclidean quantum gravity with R2R^2 interaction on spherical lattices, employing Regge's formulation. We attempt to measure the string susceptibility exponent γstr\gamma_{\rm str} by using a finite-size scaling Ansatz in the expectation value of R2R^2. To check on effects of the path integral measure we investigate two scale invariant measures, the "computer" measure dl/ldl/l and the Misner measure dl/Adl/\sqrt A.Comment: 3 pages, self unpacking uuencoded PostScript file, contribution to LATTICE9

    Oddballs and a Low Odderon Intercept

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    We report an odderon Regge trajectory emerging from a field theoretical Coulomb gauge QCD model for the odd signature JPC (P=C= -1) glueball states (oddballs). The trajectory intercept is clearly smaller than the pomeron and even the omega trajectory's intercept which provides an explanation for the nonobservation of the odderon in high energy scattering data. To further support this result we compare to glueball lattice data and also perform calculations with an alternative model based upon an exact Hamiltonian diagonalization for three constituent gluons.Comment: 4 pages, 2 figures, 1 tabl
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