65 research outputs found
Exact Rolling Tachyon in Noncommutative Field Theory
We study the exact rolling tachyon solutions in DBI type noncommutative field
theory with a constant open string metric and noncommutative parameter on an
unstable D-brane. Functional shapes of the obtained solutions span all
possible homogeneous rolling tachyon configurations; that is, they are
hyperbolic-cosine, hyperbolic-sine, and exponential under runaway NC
tachyon potential. Even if general DBI type NC electric field is turned on,
only a constant electric field satisfies the equations of motion, and again,
exact rolling tachyon solutions are obtained.Comment: 13 pages, minor correction
Deformation of the ABJM Theory
In this paper we analyse the ABJM theory on deformed spacetime. We show that
this theory reduces to a deformed super-Yang-Mills theory when one of the
scalar superfields is given a non-vanishing vacuum expectation value. Our
analyse is done in N=1 superspace formulism.Comment: 10 pages, 0 figures, accepted for publication in EP
Evolution of Tachyon Kink with Electric Field
We investigate the decay of an inhomogeneous D1-brane wrapped on a with
an electric field. The model that we consider consists of an array of tachyon
kink and anti-kink with a constant electric flux. Beginning with an initially
static configuration, we numerically evolve the tachyon field with some
perturbations under a fixed boundary condition at diametrically opposite points
on the circle . When the electric flux is smaller than the critical value,
the tachyon kink becomes unstable; the tachyon field rolls down the potential,
and the lower dimensional D0- and -brane become thin, which
resembles the caustic formation known for this type of the system in the
literature. For the supercritical values of the electric flux, the tachyon kink
remains stable.Comment: 27 pages, 8 figures, some changes, one reference added, version to
appear in JHE
Harmonic Superspace Gaugeon Formalism for the ABJM Theory
In this paper we will analyse the ABJM theory in harmonic superspace. The
harmonic superspace variables will be parameterized by the coset
and thus will have manifest supersymmetry. We will study the
quantum gauge transformations and the BRST transformations of this theory in
gaugeon formalism. We will use this BRST symmetry to project out the physical
sub-space from the total Hilbert space. We will also show that the evolution of
the -matrix is unitary for this ABJM theory in harmonic
superspace.Comment: 11, pages, 0 figures, accepted for publication in Mod. Phys. Lett.
Tachyon Kinks in Boundary String Field Theory
We study tachyon kinks with and without electromagnetic fields in the context
of boundary string field theory. For the case of pure tachyon only an array of
kink-antikink is obtained. In the presence of electromagnetic coupling, all
possible static codimension-one soliton solutions such as array of
kink-antikink, single topological BPS kink, bounce, half kink, as well as
nonBPS topological kink are found, and their properties including the
interpretation as branes are analyzed in detail. Spectrum of the obtained kinks
coincides with that of Dirac-Born-Infeld type effective theory.Comment: LaTex, 29 pages, 17 Figure
Tachyon Tube and Supertube
We search for tubular solutions in unstable D3-brane. With critical electric
field E=1, solutions representing supertubes, which are supersymmetric bound
states of fundamental strings, D0-branes, and a cylindrical D2-brane, are found
and shown to exhibit BPS-like property. We also point out that boosting such a
{\it tachyon tube} solution generates string flux winding around the tube,
resulting in helical electric fluxes on the D2-brane. We also discuss issues
related to fundamental string, absence of magnetic monopole, and finally more
tachyon tubes with noncritical electric field.Comment: 21 pages, 3 figure
Electromagnetic String Fluid in Rolling Tachyon
We study Born-Infeld type effective action for unstable D3-brane system
including a tachyon and an Abelian gauge field, and find the rolling tachyon
with constant electric and magnetic fields as the most general homogeneous
solution. Tachyonic vacua are characterized by magnitudes of the electric and
magnetic fields and the angle between them. Analysis of small fluctuations in
this background shows that the obtained configuration may be interpreted as a
fluid consisting of string-like objects carrying electric and magnetic fields.
They are stretched along one direction and the rolling tachyon move in a
perpendicular direction to the strings. Direction of the propagating waves
coincides with that of strings with velocity equal to electric field.Comment: LaTeX, 18 pages, 1 figure, minor correction
Tachyon Vacuum Solution in Open String Field Theory with Constant B Field
We show that Schnabl's tachyon vacuum solution is an exact solution of the
equation of motion of Witten's open bosonic string field theory in the
background of constant antisymmetric two-form field. The action computed at the
vacuum solution is given by the Dirac-Born-Infeld factor multiplied to that
without the antisymmetric tensor field.Comment: 8 page
Interaction between M2-branes and Bulk Form Fields
We construct the interaction terms between the world-volume fields of
multiple M2-branes and the 3- and 6-form fields in the context of ABJM theory
with U()U() gauge symmetry. A consistency check is made in the
simplest case of a single M2-brane, i.e, our construction matches the known
effective action of M2-brane coupled to antisymmetric 3-form field. We show
that when dimensionally reduced, our couplings coincide with the effective
action of D2-branes coupled to R-R 3- and 5-form fields in type IIA string
theory. We also comment on the relation between a coupling with a specific
6-form field configuration and the supersymmetry preserving mass deformation in
ABJM theory.Comment: 30 pages, version to appear in JHE
Tachyon Kinks on Unstable Dp-branes
In the context of tachyon effective theory coupled to Born-Infeld
electromagnetic fields, we obtain all possible singularity-free static flat
configurations of codimension one on unstable Dp-branes. Computed tension and
string charge density suggest that the obtained kinks are D(p-1) or
D(p-1)F1-branes.Comment: 22pages, LaTeX2e, 7figure
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