Fortschritte der Physik

Cover image for Vol. 58 Issue 6

June 2010

Volume 58, Issue 6

Pages 503–600

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Original Papers
    1. Cover Picture: Fortschritte der Physik 6 / 2010

      Article first published online: 6 MAY 2010 | DOI: 10.1002/prop.201090002

      Thumbnail image of graphical abstract

      The cover page of 2010 shows an abstract picture of the so-called string landscape. It is known for some time that, although string theory seems to be unique in ten or eleven space-time dimensions, a vast number of solutions pops out upon compactification to lower dimensions, in particular to fours space-time dimensions.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Original Papers
    1. Contents: Fortschritte der Physik 6 / 2010 (pages 503–504)

      Article first published online: 6 MAY 2010 | DOI: 10.1002/prop.201010418

  3. Original Papers

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Original Papers
    1. Evaporation of microscopic black holes in string theory and the bound on species (pages 505–527)

      G. Dvali and D. Lüst

      Article first published online: 19 APR 2010 | DOI: 10.1002/prop.201000008

      The question how string compactifications with D-branes are consistent with the black hole bound arises in any theory with number of particle species to which the black holes can evaporate. For the Kaluza-Klein particles, both longitudinal and transversal to the D-branes, it is relatively easy to see that the black hole bound is saturated, and the geometric relations can be understood in the language of species-counting. The question of the black hole evaporation into the higher string states will be addressed and it is found, that the exponentially growing number of Regge states does not preclude the existence of semi-classical black holes of sub-stringy size.

    2. Black holes and large N species solution to the hierarchy problem (pages 528–536)

      G. Dvali

      Article first published online: 19 APR 2010 | DOI: 10.1002/prop.201000009

      Perturbative and non-perturbative arguments are provided showing that theories with large number of species of the quantum fields imply an inevitable hierarchy between the masses of the species and the Planck scale. Furthermore it is shown that the gravitationally-coupled N-species sector that solves the gauge hirearchy problem, should be probed by LHC.

    3. On the fermion spectrum of spontaneously generated fuzzy extra dimensions with fluxes (pages 537–552)

      A. Chatzistavrakidis, H. Steinacker and G. Zoupanos

      Article first published online: 13 APR 2010 | DOI: 10.1002/prop.201000018

      An investigation of vacua of four-dimensional SU(N) gauge theory with the same field content as the N = 4 supersymmetric Yang-Mills theory is presented. It is shown that the theory behaves at intermediate scales as Yang-Mills theory on M4 × S2L × S2R, where the extra dimensions are fuzzy spheres with magnetic fluxes. In particular the structure of the zero modes due to the fluxes leading to low-energy mirror models are determined.

    4. Noncommutative geometry as a framework for unification of all fundamental interactions including gravity. Part I. (pages 553–600)

      A.H. Chamseddine and A. Connes

      Article first published online: 28 APR 2010 | DOI: 10.1002/prop.201000069

      Examining the hypothesis that space-time is a product of a continuous four-dimensional manifold times a finite space a new tensorial notation to present the various constructs of noncommutative geometry is developed. In particular, this notation is used to determine the spectral data of the standard model. The particle spectrum with all of its symmetries is derived, almost uniquely, under the assumption of irreducibility and of dimension 6 modulo 8 for the finite space.The leading order terms in the spectral action are re-derived. The geometrical action yields unification of all fundamental interactions including gravity at very high energies. The following predictions emerge:

      (i) The number of fermions per family is 16.

      (ii) The symmetry group is U(1) 6times; SU(2) × SU(3).

      (iii) There are quarks and leptons in the correct representations.

      (iv) There is a doublet Higgs that breaks the electroweak symmetry to U(1).

      (v) Top quark mass of 170–175 GeV.

      (vi) There is a right-handed neutrino with a see-saw mechanism.

      The influence of higher order corrections to the predicted mass of the Higgs field, the nature of the noncommutative space at Planckian energies and the possible role of the fundamental group for the problem of generations are discussed.