66 research outputs found
On Gauge Equivalence of Tachyon Solutions in Cubic Neveu-Schwarz String Field Theory
Simple analytic solution to cubic Neveu-Schwarz String Field Theory including
the sector is presented. This solution is an analog of the
Erler-Schnabl solution for bosonic case and one of the authors solution for the
pure case. Gauge transformations of the new solution to others known
solutions for the string tachyon condensation are constructed explicitly.
This gauge equivalence manifestly supports the early observed fact that these
solutions have the same value of the action density.Comment: 8 pages, LaTe
Descent Relations and Oscillator Level Truncation Method
We reexamine the oscillator level truncation method in the bosonic String
Field Theory (SFT) by calculation the descent relation =Z_3<V_2|. For
the ghost sector we use the fermionic vertices in the standard oscillator
basis. We propose two new schemes for calculations. In the first one we assume
that the insertion satisfies the overlap equation for the vertices and in the
second one we use the direct calculations. In both schemes we get the correct
structures of the exponent and pre-exponent of the vertex <V_2|, but we find
out different normalization factors Z_3.Comment: 21 pages, 10 figures, Late
Twist Symmetry and Classical Solutions in Open String Field Theory
We construct classical solutions of open string field theory which are not
invariant under ordinary twist operation. From detailed analysis of the moduli
space of the solutions, it turns out that our solutions become nontrivial at
boundaries of the moduli space. The cohomology of the modified BRST operator
and the CSFT potential evaluated by the level truncation method strongly
support the fact that our nontrivial solutions correspond to the closed string
vacuum. We show that the nontrivial solutions are equivalent to the twist even
solution which was found by Takahashi and Tanimoto, and twist invariance of
open string field theory remains after the shift of the classical backgrounds.Comment: 19 pages, 2 figures; v2: errors fixe
Comments on regularization of identity based solutions in string field theory
We analyze the consistency of the recently proposed regularization of an
identity based solution in open bosonic string field theory. We show that the
equation of motion is satisfied when it is contracted with the regularized
solution itself. Additionally, we propose a similar regularization of an
identity based solution in the modified cubic superstring field theory.Comment: 24 pages, two subsections added, two references adde
Non-minimally Coupled Cosmological Models with the Higgs-like Potentials and Negative Cosmological Constant
We study dynamics of non-minimally coupled scalar field cosmological models
with Higgs-like potentials and a negative cosmological constant. In these
models the inflationary stage of the Universe evolution changes into a
quasi-cyclic stage of the Universe evolution with oscillation behaviour of the
Hubble parameter from positive to negative values. Depending on the initial
conditions the Hubble parameter can perform either one or several cycles before
to become negative forever.Comment: 22 pages, 6 figures, v4:Section 2 expanded, references added,
accepted for publication in Class. Quant. Gra
Superstring field theory equivalence: Ramond sector
We prove that the finite gauge transformation of the Ramond sector of the
modified cubic superstring field theory is ill-defined due to collisions of
picture changing operators.
Despite this problem we study to what extent could a bijective classical
correspondence between this theory and the (presumably consistent)
non-polynomial theory exist. We find that the classical equivalence between
these two theories can almost be extended to the Ramond sector: We construct
mappings between the string fields (NS and Ramond, including Chan-Paton factors
and the various GSO sectors) of the two theories that send solutions to
solutions in a way that respects the linearized gauge symmetries in both sides
and keeps the action of the solutions invariant. The perturbative spectrum
around equivalent solutions is also isomorphic.
The problem with the cubic theory implies that the correspondence of the
linearized gauge symmetries cannot be extended to a correspondence of the
finite gauge symmetries. Hence, our equivalence is only formal, since it
relates a consistent theory to an inconsistent one. Nonetheless, we believe
that the fact that the equivalence formally works suggests that a consistent
modification of the cubic theory exists. We construct a theory that can be
considered as a first step towards a consistent RNS cubic theory.Comment: v1: 24 pages. v2: 27 pages, significant modifications of the
presentation, new section, typos corrected, references adde
Solutions from boundary condition changing operators in open string field theory
We construct analytic solutions of open string field theory using boundary
condition changing (bcc) operators. We focus on bcc operators with vanishing
conformal weight such as those for regular marginal deformations of the
background. For any Fock space state phi, the component string field
of the solution Psi exhibits a remarkable factorization property: it is given
by the matter three-point function of phi with a pair of bcc operators,
multiplied by a universal function that only depends on the conformal weight of
phi. This universal function is given by a simple integral expression that can
be computed once and for all. The three-point functions with bcc operators are
thus the only needed physical input of the particular open string background
described by the solution. We illustrate our solution with the example of the
rolling tachyon profile, for which we prove convergence analytically. The form
of our solution, which involves bcc operators instead of explicit insertions of
the marginal operator, can be a natural starting point for the construction of
analytic solutions for arbitrary backgrounds.Comment: 21 pages, 1 figure, LaTeX2e; v2: minor changes, version published in
JHE
Statefinder Parameters for Interacting Phantom Energy with Dark Matter
We apply in this paper the statefinder parameters to the interacting phantom
energy with dark matter. There are two kinds of scaling solutions in this
model. It is found that the evolving trajectories of these two scaling
solutions in the statefinder parameter plane are quite different, and that are
also different from the statefinder diagnostic of other dark energy models.Comment: 9 pages, 12 figures, some references are added, some words are
modifie
On the non-Abelian Stokes theorem for SU(2) gauge fields
We derive a version of non-Abelian Stokes theorem for SU(2) gauge fields in
which neither additional integration nor surface ordering are required. The
path ordering is eliminated by introducing the instantaneous color orientation
of the flux. We also derive the non-Abelian Stokes theorem on the lattice and
discuss various terms contributing to the trace of the Wilson loop.Comment: Latex2e, 0+14 pages, 3 figure
Relevant Deformations in Open String Field Theory: a Simple Solution for Lumps
We propose a remarkably simple solution of cubic open string field theory
which describes inhomogeneous tachyon condensation. The solution is in
one-to-one correspondence with the IR fixed point of the RG-flow generated in
the two--dimensional world-sheet theory by integrating a relevant operator with
mild enough OPE on the boundary. It is shown how the closed string overlap
correctly captures the shift in the closed string one point function between
the UV and the IR limits of the flow. Examples of lumps in non-compact and
compact transverse directions are given.Comment: 45 pages. v2: typos and minor improvements. v3: submitted to jhe
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