Browsing by Author "Maccaferri, Carlo"
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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 TheoryWe 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.Item Chan-Paton factors and Higgsing from Vacuum String Field Theory(2005) Maccaferri, Carlo; Physics; Elementary Particle TheoryWe give a description of open strings stretched between N parallel D-branes in VSFT. We show how higgsing is generated as the branes are displaced: the shift in the mass formula for on-shell states stretched between different branes is due to a twist anomaly, a contribution localized at the midpoint.Item Fundamental strings in SFT(2005) Bonora, Loriano; Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie; Physics; Elementary Particle TheoryIn 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).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 TheoryThis 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.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 TheoryWe 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.Item Topics in String Field Theory(SISSA, 2003) Bonora, Loriano; Maccaferri, Carlo; Mamone, Davide; Salizzoni, Mario; Physics; Elementary Particle TheoryThis review of bosonic string field theory is concentrated on two main subjects. In the first part we revisit the construction of the three string vertex and rederive the relevant Neumann coefficients both for the matter and the ghost part following a conformal field theory approach. We use this formulation to solve the VSFT equation of motion for the ghost sector. This part of the paper is based on a new method which allows us to derive known results in a simpler way. In the second part we concentrate on the solution of the VSFT equation of motion for the matter part. We describe the construction of the three strings vertex in the presence of a background B field. We determine a large family of lump solutions, illustrate their interpretation as D-branes and study the low energy limit. We show that in this limit the lump solutions flow toward the so-called GMS solitons.Item Towards open-closed string duality: Closed Strings as Open String Fields(2006-10-04T10:55:15Z) Bonora, Loriano; Bouatta, N.; Maccaferri, Carlo; Physics; Elementary Particle TheoryWe establish a translation dictionary between open and closed strings, starting from open string field theory. Under this correspondence, (off-shell) level-matched closed string states are represented by star algebra projectors in open string field theory. Particular attention is paid to the zero mode sector, which is indispensable in order to generate closed string states with momentum. As an outcome of our identification, we show that boundary states, which in closed string theory represent D-branes, correspond to the identity string field in the open string side. It is to be remarked that closed string theory D-branes are thus given by an infinite superposition of star algebra projectors.