Browsing by Author "Tolla, Driba Demissie"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Bubbling AdS and Vacuum String Field Theory
    (2006-04-12T09:01:49Z) Bonora, Loriano; Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    We show that a family of 1/2--BPS states of $\N=4$ SYM is in correspondence with a family of classical solutions of VSFT with a $B$--field playing the role of the inverse Planck constant. We show this correspondence by relating the Wigner distributions of the $N$ fermion systems representing such states, to low energy space profiles of systems of VSFT D-branes. In this context the Pauli exclusion principle appears as a consequence of the VSFT projector equation. The family of 1/2--BPS states maps through coarse--graining to droplet LLM supergravity solutions. We discuss the possible meaning of the corresponding coarse graining in the VSFT side.
  • Thumbnail Image
    Item
    Fundamental strings in SFT
    (2005) Bonora, Loriano; Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    In this letter we show that vacuum string field theory contains exact solutions that can be interpreted as macroscopic fundamental strings. They are formed by a condensate of infinitely many completely space-localized solutions (D0-branes).
  • Thumbnail Image
    Item
    Ghost story. I. Wedge states in the oscillator formalism
    (2007-06-11T09:16:56Z) Bonora, Loriano; Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    This paper is primarily devoted to the ghost wedge states in string field theory formulated with the oscillator formalism. Our aim is to prove, using such formalism, that the wedge states can be expressed as |n> = exp[{2-n}/2 ({\cal L}_0+{\cal L}_0^\daggert)]|0>, separately in the matter and ghost sector. This relation is crucial for instance in the proof of Schnabl's solution. We start from the exponentials in the rhs and wish to prove that they take precisely the form of wedge states. As a guideline we first re-demonstrate this relation for the matter part. Then we turn to the ghosts. On the way we face the problem of `diagonalizing' infinite rectangular matrices. We manage to give a meaning to such an operation and to prove that the eigenvalues we obtain satisfy the recursion relations of the wedge states.
  • Thumbnail Image
    Item
    Light-cone Superstring Field Theory, pp-wave background and integrability properties
    (2005) Bonora, Loriano; Scherer Santos, Ricardo Jose; Sorin, Alexander S.; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    We show that the three strings vertex coefficients in light-cone open string field theory satisfy the Hirota equations for the ispersionless Toda lattice hierarchy. We show that Hirota equations allow us to calculate the correlators of an associated quantum system where the Neumann coefficients represent the two-point functions.
  • Thumbnail Image
    Item
    Lump solutions in SFT. Complements
    (SISSA, 2011-09-20) Bonora, Loriano; Giaccari, Stefano; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    Recently a possible violation of the equation of motion for the recently proposed lump solutions in open SFT has been pointed out in the literature. In this paper we argue that, when the issue is considered in the appropriate mathematical setting of distribution theory, no violations to the equation of motion occur.
  • Thumbnail Image
    Item
    Time-localized projectors in string field theory with e-field
    (2005-06-20T14:05:22Z) Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie; Physics; Elementary Particle Theory
    We extend the analysis of hep-th/0409063 to the case of a constant electric field turned on the worldvolume and on a transverse direction of a D-brane. We show that time localization is still obtained by inverting the discrete eigenvalues of the lump solution. The lifetime of the unstable soliton is shown to depend on two free parameters: the b-parameter and the value of the electric field. As a by-product, we construct the normalized diagonal basis of the star algebra in Bµν–field background.