486 research outputs found
Cornering the unphysical vertex
In the classical pure spinor worldsheet theory of AdS5xS5 there are some
vertex operators which do not correspond to any physical excitations. We study
their flat space limit. We find that the BRST operator of the worldsheet theory
in flat space-time can be nontrivially deformed without deforming the
worldsheet action. Some of these deformations describe the linear dilaton
background. But the deformation corresponding to the nonphysical vertex differs
from the linear dilaton in not being worldsheet parity even. The nonphysically
deformed worldsheet theory has nonzero beta-function at one loop. This means
that the classical Type IIB SUGRA backgrounds are not completely characterized
by requiring the BRST symmetry of the classical worldsheet theory; it is also
necessary to require the vanishing of the one-loop beta-function.Comment: LaTeX 40pp; v2: explained the relation to the linear dilaton
background (Section 6), changes in Introduction and Abstrac
The One-loop Open Superstring Massless Five-point Amplitude with the Non-Minimal Pure Spinor Formalism
We compute the massless five-point amplitude of open superstrings using the
non-minimal pure spinor formalism and obtain a simple kinematic factor in pure
spinor superspace, which can be viewed as the natural extension of the
kinematic factor of the massless four-point amplitude. It encodes bosonic and
fermionic external states in supersymmetric form and reduces to existing
bosonic amplitudes when expanded in components, therefore proving their
equivalence. We also show how to compute the kinematic structures involving
fermionic states.Comment: 38 pages, harvmac TeX, v2: fix typo in (4.2) and add referenc
Integrability of Type II Superstrings on Ramond-Ramond Backgrounds in Various Dimensions
We consider type II superstrings on AdS backgrounds with Ramond-Ramond flux
in various dimensions. We realize the backgrounds as supercosets and analyze
explicitly two classes of models: non-critical superstrings on AdS_{2d} and
critical superstrings on AdS_p\times S^p\times CY. We work both in the
Green--Schwarz and in the pure spinor formalisms. We construct a one-parameter
family of flat currents (a Lax connection) leading to an infinite number of
conserved non-local charges, which imply the classical integrability of both
sigma-models. In the pure spinor formulation, we use the BRST symmetry to prove
the quantum integrability of the sigma-model. We discuss how classical
\kappa-symmetry implies one-loop conformal invariance. We consider the addition
of space-filling D-branes to the pure spinor formalism.Comment: LaTeX2e, 56 pages, 1 figure, JHEP style; v2: references added, typos
fixed in some equations; v3: typos fixed to match the published versio
Non-Critical Pure Spinor Superstrings
We construct non-critical pure spinor superstrings in two, four and six
dimensions. We find explicitly the map between the RNS variables and the pure
spinor ones in the linear dilaton background. The RNS variables map onto a
patch of the pure spinor space and the holomorphic top form on the pure spinor
space is an essential ingredient of the mapping. A basic feature of the map is
the requirement of doubling the superspace, which we analyze in detail. We
study the structure of the non-critical pure spinor space, which is different
from the ten-dimensional one, and its quantum anomalies. We compute the pure
spinor lowest lying BRST cohomology and find an agreement with the RNS spectra.
The analysis is generalized to curved backgrounds and we construct as an
example the non-critical pure spinor type IIA superstring on AdS_4 with RR
4-form flux.Comment: LaTeX2e, 76 pages, no figures, JHEP style; v2: references and
acknowledgments added, typos corrected; v3: typos corrected and minor changes
to match published versio
Hybrid Formalism, Supersymmetry Reduction, and Ramond-Ramond Fluxes
The supersymmetric hybrid formalism for Type II strings is used to study
partial supersymmetry breaking in four and three dimensions. We use worldsheet
techniques to derive effects of internal Ramond-Ramond fluxes such as torsions,
superpotentials and warping.Comment: Harvmac. No figure
Superstrings and Topological Strings at Large N
We embed the large N Chern-Simons/topological string duality in ordinary
superstrings. This corresponds to a large duality between generalized gauge
systems with N=1 supersymmetry in 4 dimensions and superstrings propagating on
non-compact Calabi-Yau manifolds with certain fluxes turned on. We also show
that in a particular limit of the N=1 gauge theory system, certain
superpotential terms in the N=1 system (including deformations if spacetime is
non-commutative) are captured to all orders in 1/N by the amplitudes of
non-critical bosonic strings propagating on a circle with self-dual radius. We
also consider D-brane/anti-D-brane system wrapped over vanishing cycles of
compact Calabi-Yau manifolds and argue that at large they induce a shift in
the background to a topologically distinct Calabi-Yau, which we identify as the
ground state system of the Brane/anti-Brane system.Comment: 30 pages, some minor clarifications adde
Pasti-Sorokin-Tonin Actions in the Presence of Sources
Pasti, Sorokin and Tonin have recently constructed manifestly
Lorentz-invariant actions for self-dual field strengths and for Maxwell fields
with manifest electromagnetic duality. Using the method of Deser, Gomberoff,
Henneaux and Teitelboim, we generalize these actions in the presence of
sources.Comment: 6 pages, LaTe
Vertex Operators for Closed Superstrings
We construct an iterative procedure to compute the vertex operators of the
closed superstring in the covariant formalism given a solution of IIA/IIB
supergravity. The manifest supersymmetry allows us to construct vertex
operators for any generic background in presence of Ramond-Ramond (RR) fields.
We extend the procedure to all massive states of open and closed superstrings
and we identify two new nilpotent charges which are used to impose the gauge
fixing on the physical states. We solve iteratively the equations of the vertex
for linear x-dependent RR field strengths. This vertex plays a role in studying
non-constant C-deformations of superspace. Finally, we construct an action for
the free massless sector of closed strings, and we propose a form for the
kinetic term for closed string field theory in the pure spinor formalism.Comment: TeX, harvmac, amssym.tex, 41 pp; references adde
Decoupling of unphysical states in the minimal pure spinor formalism I
This is the first of a series of two papers where decoupling of unphysical
states in the minimal pure spinor formalism is investigated. The multi-loop
amplitude prescription for the minimal pure spinor superstring formulated in
hep-th/0406055 involves the insertion of picture changing operators in the path
integral. These operators are BRST closed in a distributional sense and depend
on a number of constant tensors. One can trace the origin of these insertions
to gauge fixing, so the amplitudes are formally independent of the constant
tensors. We show however by explicit tree-level and one-loop computations that
the picture changing operators are not BRST closed inside correlators and the
amplitudes do depend on these constant tensors. This is due to the fact that
the gauge fixing condition implicit in the existing minimal amplitude
prescription is singular and this can lead to Lorentz violation and
non-decoupling of BRST exact states. As discussed in hep-th/0406055, a
manifestly Lorentz invariant prescription can be obtained by integrating over
the constant tensors and in the sequel to this paper, it is shown that when one
includes these integrations unphysical states do decouple to all orders despite
the fact that the PCO's are not BRST closed inside correlators.Comment: 77 pages (51 pages + appendices), added hyperref
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