3,523 research outputs found
Is the String Coupling Constant invariant under T-duality?
It is well known that under T-duality the sigma model dilaton (which is
normally thought to be related to the string coupling constant through the
simple formula ), undergoes an additive shift. On the
other hand, Kugo and Zwiebach, using a simplified form of string field theory,
claim that the string coupling constant does not change under the T-duality.
Obviously, what seems to happen is that two different coupling constants,
associated to different dilatons, are used. In this contribution we shall try
to clarify this, and related issues.Comment: LaTeX, 13 pag. Contributions to Santa Margherita and S. Petersburg
meeting
Background Independent Algebraic Structures in Closed String Field Theory
We construct a Batalin-Vilkovisky (BV) algebra on moduli spaces of Riemann
surfaces. This algebra is background independent in that it makes no reference
to a state space of a conformal field theory. Conformal theories define a
homomorphism of this algebra to the BV algebra of string functionals. The
construction begins with a graded-commutative free associative algebra \C
built from the vector space whose elements are orientable subspaces of moduli
spaces of punctured Riemann surfaces. The typical element here is a surface
with several connected components. The operation of sewing two
punctures with a full twist is shown to be an odd, second order derivation that
squares to zero. It follows that (\C, \Delta) is a Batalin-Vilkovisky
algebra. We introduce the odd operator , where
is the boundary operator. It is seen that , and that
consistent closed string vertices define a cohomology class of . This
cohomology class is used to construct a Lie algebra on a quotient space of
\C. This Lie algebra gives a manifestly background independent description of
a subalgebra of the closed string gauge algebra.Comment: phyzzx.tex, MIT-CTP-234
The Perturbative Spectrum of the Dressed Sliver
We analyze the fluctuations of the dressed sliver solution found in a
previous paper, hep-th/0311198, in the operator formulation of Vacuum String
Field Theory. We derive the tachyon wave function and then analyze the higher
level fluctuations. We show that the dressing is responsible for implementing
the transversality condition on the massless vector. In order to consistently
deal with the singular mode we introduce a string midpoint regulator and
we show that it is possible to accommodate all the open string states among the
solutions to the linearized equations of motion. We finally show how the
dressing can give rise to the correct ratio between the energy density of the
dressed sliver and the brane tension computed via the three-tachyons-coupling.Comment: 52 pages, v2: comment added in sec. 5, v3: one appendix added,
comments added in introduction and conclusion, to appear on PR
Boundary states as exact solutions of (vacuum) closed string field theory
We show that the boundary states are idempotent B*B=B with respect to the
star product of HIKKO type closed string field theory. Variations around the
boundary state correctly reproduce the open string spectrum with the gauge
symmetry. We explicitly demonstrate it for the tachyonic and massless vector
modes. The idempotency relation may be regarded as the equation of motion of
closed string field theory at a possible vacuum.Comment: 30 pages, 2 figures, v3:regularization improve
Prosomal-width-to-weight relationships in American horseshoe crabs (Limulus polyphemus): examining conversion factors used to estimate landings
Horseshoe crabs (Limulus polyphemus) are valued by many
stakeholders, including the commercial fishing industry, biomedical companies, and environmental interest groups. We designed a study to test the accuracy of the conversion factors that were used by NOAA Fisheries and state agencies to estimate horseshoe crab landings before mandatory
reporting that began in 1998. Our results indicate that the NOAA Fisheries conversion factor consistently overestimates the weight of male horseshoe crabs, particularly those from New England populations. Because of the inaccuracy of this and other conversion factors, states are now mandated to report the number (not biomass) and sex of landed horseshoe
crabs. However, accurate estimates of biomass are still necessary for use in prediction models that are being developed to better manage the horseshoe crab fishery. We recommend that managers use the conversion factors presented in this study to convert current landing data from numbers to biomass of harvested horseshoe crabs
for future assessments
Chan-Paton factors and Higgsing from Vacuum String Field Theory
We give a description of open strings stretched between N parallel D-branes
in VSFT. We show how higgsing is generated as the branes are displaced: the
shift in the mass formula for on-shell states stretched between different
branes is due to a twist anomaly, a contribution localized at the midpoint.Comment: 20 pages, JHEP clas
Nonnucleosynthetic Constraints on the Baryon Density and Other Cosmological Parameters
Because the baryon-to-photon ratio η_10 is in some doubt, we drop nucleosynthetic constraints on η_10 and fit the three cosmological parameters (h, Ω_M, η_10) to four observational constraints: Hubble parameter h_o = 0.70 ± 0.15, age of the universe t_0 =14^+7_-2 Gyr, cluster gas fraction f_o ⥠f_G h^3/2 = 0.060 ± 0.006, and effective shape parameter Î_o = 0.255 ± 0.017. Errors quoted are 1 Ï, and we assume Gaussian statistics. We experiment with a fifth constraint Ω_o = 0.2 ± 0.1 from clusters. We set the tilt parameter n = 1 and the gas enhancement factor Upsilon = 0.9. We consider cold dark matter models (open and Ω_M = 1) and flat ÎCDM models. We omit HCDM models (to which the Î_o constraint does not apply). We test goodness of fit and draw confidence regions by the ÎÏ^2 method. CDM models with Ω_M = 1 (SCDM models) are accepted only because the large error on h_o allows h 0.4. The combination of the four other constraints with Ωo approx 0.2 is rejected in CDM models with 98% confidence, suggesting that light may not trace mass. ÎCDM models give similar results. In all of these models, η_10 ~> 6 is favored strongly over η_10 ~< 2. This suggests that reports of low deuterium abundances on QSO lines of sight may be correct and that observational determinations of primordial ^4He may have systematic errors. Plausible variations on n and Upsilon in our models do not change the results much. If we drop or change the crucial Î_o constraint, lower values of Ω_M and η_10 are permitted. The constraint Î_o = 0.15 ± 0.04, derived recently from the IRAS redshift survey, favors Ω_M approx 0.3 and η_10 approx 5 but does not exclude η_10 approx 2
Winding Number in String Field Theory
Motivated by the similarity between cubic string field theory (CSFT) and the
Chern-Simons theory in three dimensions, we study the possibility of
interpreting N=(\pi^2/3)\int(U Q_B U^{-1})^3 as a kind of winding number in
CSFT taking quantized values. In particular, we focus on the expression of N as
the integration of a BRST-exact quantity, N=\int Q_B A, which vanishes
identically in naive treatments. For realizing non-trivial N, we need a
regularization for divergences from the zero eigenvalue of the operator K in
the KBc algebra. This regularization must at same time violate the
BRST-exactness of the integrand of N. By adopting the regularization of
shifting K by a positive infinitesimal, we obtain the desired value
N[(U_tv)^{\pm 1}]=\mp 1 for U_tv corresponding to the tachyon vacuum. However,
we find that N[(U_tv)^{\pm 2}] differs from \mp 2, the value expected from the
additive law of N. This result may be understood from the fact that \Psi=U Q_B
U^{-1} with U=(U_tv)^{\pm 2} does not satisfy the CSFT EOM in the strong sense
and hence is not truly a pure-gauge in our regularization.Comment: 20 pages, no figures; v2: references added, minor change
Stochastic Hamiltonian for Non-Critical String Field Theories from Double-Scaled Matrix Models
We present detailed discussions on the stochastic Hamiltonians for
non-critical string field theories on the basis of matrix models. Beginning
from the simplest case, we derive the explicit forms of the Hamiltonians
for the higher critical case (which corresponds to ) and for the
case , directly from the double-scaled matrix models. In particular, for
the two-matrix case, we do not put any restrictions on the spin configurations
of the string fields. The properties of the resulting infinite algebras of
Schwinger-Dyson operators associated with the Hamiltonians and the derivation
of the Virasoro and algebras therefrom are also investigated. Our results
suggest certain universal structure of the stochastic Hamiltonians, which might
be useful for an attempt towards a background independent string field theory.Comment: 70 pages, LaTeX, typographical errors are corrected, to be published
in Phys. Rev.
Time Dependent Solution in Cubic String Field Theory
We study time dependent solutions in cubic open string field theory which are
expected to describe the configuration of the rolling tachyon. We consider the
truncated system consisting of component fields of level zero and two, which
are expanded in terms of cosh n x^0 modes. For studying the large time behavior
of the solution we need to know the coefficients of all and, in particular,
large n modes. We examine numerically the coefficients of the n-th mode, and
find that it has the leading n-dependence of the form (-\beta)^n \lambda^{-n^2}
multiplied by a peculiar subleading part with peaks at
n=2^m=4,8,16,32,64,128,.... This behavior is also reproduced analytically by
solving simplified equations of motion of the tachyon system.Comment: 22 pages, 12 figures, LaTeX2e, v3:minor correction
- âŠ