501 research outputs found
Wedge states in string field theory
The wedge states form an important subalgebra in the string field theory. We
review and further investigate their various properties. We find in particular
a novel expression for the wedge states, which allows to understand their star
products purely algebraically. The method allows also for treating the matter
and ghost sectors separately. It turns out, that wedge states with different
matter and ghost parts violate the associativity of the algebra. We introduce
and study also wedge states with insertions of local operators and show how
they are useful for obtaining exact results about convergence of level
truncation calculations. These results help to clarify the issue of anomalies
related to the identity and some exterior derivations in the string field
algebra.Comment: 40 pages, 9 figures, v3: section 3.3 rewritten, few other
corrections, set in JHEP styl
Exact Solutions of Open Bosonic String Field Theory
In this paper we present two solutions of open bosonic string field theory
defined on D0-brane background that correspond to the change of the D0-brane
position in the transverse space.Comment: 18 page
Some exact computations on the twisted butterfly state in string field theory
The twisted butterfly state solves the equation of motion of vacuum string
field theory in the singular limit. The finiteness of the energy density of the
solution is an important issue, but possible conformal anomaly resulting from
the twisting has prevented us from addressing this problem. We present a
description of the twisted regulated butterfly state in terms of a conformal
field theory with a vanishing central charge which consists of the ordinary bc
ghosts and a matter system with c=26. Various quantities relevant to vacuum
string field theory are computed exactly using this description. We find that
the energy density of the solution can be finite in the limit, but the
finiteness depends on the subleading structure of vacuum string field theory.
We further argue, contrary to our previous expectation, that contributions from
subleading terms in the kinetic term to the energy density can be of the same
order as the contribution from the leading term which consists of the midpoint
ghost insertion.Comment: 36 pages, no figures, LaTeX2e; v2: minor corrections; v3: typos
corrected, published in JHEP; v4: a minor typo in (C.12) correcte
Marginal Deformations In the Open Bosonic String Field Theory for N D0-branes
In this short note we give an example of the exact solution of the open
bosonic string field theory defined on the background of coincided
D0-branes. This solution leads to the change of the original background to the
background where D0-branes are localised in general positions.Comment: 14 page
Exact Solutions in SFT and Marginal Deformation in BCFT
In this note we will study solution of open bosonic string field theory based
on action of operators from chiral algebra of boundary conformal field theory
on identity element of string field theory star algebra. We will demonstrate
that the string field theory action for fluctuation fields around this
classical solution can be mapped to the string field theory action defined
through the new boundary conformal field theory that arises from the original
one through the marginal deformation inserted on the world-sheet boundary.Comment: 15 pages, references adde
Rolling Tachyon Solution in Vacuum String Field Theory
We construct a time-dependent solution in vacuum string field theory and
investigate whether the solution can be regarded as a rolling tachyon solution.
First, compactifying one space direction on a circle of radius R, we construct
a space-dependent solution given as an infinite number of *-products of a
string field with center-of-mass momentum dependence of the form e^{-b p^2/4}.
Our time-dependent solution is obtained by an inverse Wick rotation of the
compactified space direction. We focus on one particular component field of the
solution, which takes the form of the partition function of a Coulomb system on
a circle with temperature R^2. Analyzing this component field both analytically
and numerically using Monte Carlo simulation, we find that the parameter b in
the solution must be set equal to zero for the solution to approach a finite
value in the large time limit x^0\to\infty. We also explore the possibility
that the self-dual radius R=\sqrt{\alpha'} is a phase transition point of our
Coulomb system.Comment: 39 pages, 17 figures, v3: references adde
On Continuous Moyal Product Structure in String Field Theory
We consider a diagonalization of Witten's star product for a ghost system of
arbitrary background charge and Grassmann parity. To this end we use a
bosonized formulation of such systems and a spectral analysis of Neumann
matrices. We further identify a continuous Moyal product structure for a
combined ghosts+matter system. The normalization of multiplication kernel is
discussed.Comment: 18+7 pages, 1 figure, typos correction
Towards Vacuum Superstring Field Theory: The Supersliver
We extend some aspects of vacuum string field theory to superstring field
theory in Berkovits' formulation, and we study the star algebra in the
fermionic matter sector. After clarifying the structure of the interaction
vertex in the operator formalism of Gross and Jevicki, we provide an algebraic
construction of the supersliver state in terms of infinite-dimensional
matrices. This state is an idempotent string field and solves the matter part
of the equation of motion of superstring field theory with a pure ghost BRST
operator. We determine the spectrum of eigenvalues and eigenvectors of the
infinite-dimensional matrices of Neumann coefficients in the fermionic matter
sector. We then analyze coherent states based on the supersliver and use them
in order to construct higher-rank projector solutions, as well as to construct
closed subalgebras of the star algebra in the fermionic matter sector. Finally,
we show that the geometric supersliver is a solution to the superstring field
theory equations of motion, including the (super)ghost sector, with the
canonical choice of vacuum BRST operator recently proposed by Gaiotto,
Rastelli, Sen and Zwiebach.Comment: 45 pages, JHEP styl
Construction of the Vacuum String Field Theory on a non-BPS Brane
In the framework of the Sen conjectures a construction of vacuum superstring
field theory on a non-BPS brane is discussed. A distinguished feature of this
theory is a presence of a ghost kinetic operator mixing GSO+/- sectors. A
candidate for such kinetic operator with zero cohomology is discussed.Comment: expression for the pure ghost kinetic operator corrected, Comments
added; 21 pages, 1 figure, LaTeX 2
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