88 research outputs found
Membranes on Calibrations
M2-branes can blow up into BPS funnels that end on calibrated intersections
of M5-branes. In this quick note, we make the observation that the constraints
required for the consistency of these solutions are automatic in
Bagger-Lambert-Gustavsson (BLG) theory, thanks to the fundamental identity and
the supersymmetry of the calibration. We use this to explain how the previous
ad hoc fuzzy funnel constructions emerge in this picture, and make some
comments about the role of the 3-algebra trace form in the derivation.Comment: 9 pages, no figures; references added, minor change
Large BCFT moduli in open string field theory
We use the recently constructed solution for marginal deformations by one of
the authors, to analytically relate the BCFT modulus (lambda_BCFT) to the
coefficient of the boundary marginal field in the solution (lambda_SFT). We
explicitly find that the relation is not one to one and the same value of
lambda_SFT corresponds to a pair of different lambda_BCFT 's: a "small" one,
and a "large" one. The BCFT moduli space is fully covered, but the coefficient
of the marginal field in the solution is not a good global coordinate on such a
space.Comment: 14 pages, 3 figures. v2: minor notation improvements, version
published in JHE
String Field Theory Solution for Any Open String Background
We present an exact solution of open bosonic string field theory which can be
used to describe any time-independent open string background. The solution
generalizes an earlier construction of Kiermaier, Okawa, and Soler, and assumes
the existence of boundary condition changing operators with nonsingular OPEs
and vanishing conformal dimension. Our main observation is that boundary
condition changing operators of this kind can describe nearly any open string
background provided the background shift is accompanied by a timelike Wilson
line of sufficient strength. As an application we analyze the tachyon lump
describing the formation of a D-brane in the string field theory of a
D-brane, for generic compactification radius. This not only provides a proof
of Sen's second conjecture, but also gives explicit examples of higher energy
solutions, confirming analytically that string field theory can "reverse" the
direction of the worldsheet RG flow. We also find multiple D-brane solutions,
demonstrating that string field theory can add Chan-Paton factors and change
the rank of the gauge group. Finally, we show how the solution provides a
remarkably simple and nonperturbative proof of the background independence of
open bosonic string field theory.Comment: V2: 42 pages, 11 figures, typos correcte
Localization of effective actions in open superstring field theory: small Hilbert space
We consider the algebraic effective couplings for open superstring massless
modes in the framework of the theory in the small Hilbert space.
Focusing on quartic algebraic couplings, we reduce the effective action of the
theory to the Berkovits one where we have already shown that such
couplings are fully computed from contributions at the boundary of moduli
space, when the massless fields under consideration are appropriately charged
under an -symmetry. Here we offer a proof of localization
which is in the small Hilbert space. We also discuss the flat directions of the
obtained quartic potentials and give evidence for the existence of exactly
marginal deformations in the system in the framework of string field
theory.Comment: 34 pages, no figures. V2: Improved presentation, typos correcte
Localization of effective actions in open superstring field theory
We consider the construction of the algebraic part of D-branes tree-level
effective action from Berkovits open superstring field theory. Applying this
construction to the quartic potential of massless fields carrying a specific
worldsheet charge, we show that the full contribution to the potential
localizes at the boundary of moduli space, reducing to elementary two-point
functions. As examples of this general mechanism, we show how the Yang-Mills
quartic potential and the instanton effective action of a system
are reproducedComment: 30 pages (incl appendix). No figure
BCFT and OSFT moduli: an exact perturbative comparison
Starting from the pseudo- gauge solution for marginal
deformations in OSFT, we analytically compute the relation between the
perturbative deformation parameter in the solution and the BCFT
marginal parameter , up to fifth order, by evaluating the Ellwood
invariants. We observe that the microscopic reason why and
are different is that the OSFT propagator renormalizes contact term
divergences differently from the contour deformation used in BCFTComment: 26+5 pages, 10 figures V2: minor improvements, published versio
M2-brane Flows and the Chern-Simons Level
The Chern-Simons level k of ABJM gauge theory captures the orbifolding in the
dual geometry. This suggests that if we move the membranes away from the tip of
the orbifold to a smooth point, it should trigger an RG flow that changes the
level to k=1 in the IR. We construct an explicit supergravity solution that is
dual to this shift from generic k to k=1. In the gauge theory side, we present
arguments for why this shift is plausible at the end of the RG flow. We also
consider a resolution of the orbifold for the case k=4 (where explicit metrics
can be found), and construct the smooth supergravity solution that interpolates
between AdS4 X S7/Z4 and AdS4 X S7, corresponding to localized branes on the
blown up six cycle. In the gauge theory, we make some comments about the
dimension four operator dual to the resolution as well as the associated RG
flow.Comment: v4: figure with typo replaced, clarifications added. 35 p
String Field Theory
String Field Theory is a formulation of String Theory as a Quantum Field
Theory in target space. It allows to tame the infrared divergences of String
Theory and to approach its non-perturbative structure and background
independence. This article gives a concise overview on the subject and of some
of the main recent progresses.
Note: Review article for Oxford Research Encyclopedia of PhysicsComment: 33 pages, no figures. Invited contribution to Oxford Research
Encyclopedia of Physic
A simple solution for marginal deformations in open string field theory
We derive a new open string field theory solution for boundary marginal
deformations generated by chiral currents with singular self-OPE. The solution
is algebraically identical to the Kiermaier-Okawa-Soler solution and it is
gauge equivalent to the Takahashi-Tanimoto identity-based solution. It is
wedge-based and we can analytically evaluate the Ellwood invariant and the
action, reproducing the expected results from BCFT. By studying the isomorphism
between the states of the initial and final background a dual derivation of the
Ellwood invariant is also obtained.Comment: 34 pages, no figures V3: typos and minors, one ref. added, published
versio
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