We study non-BPS D-branes in the type II string vacua with chiral space-time SUSY constructed based on the asymmetric orbifolds of $\mbox{K3} \cong T^4/{\Bbb Z}_2$ as a succeeding work of arXiv:1704.05262[hep-th]. We especially focus on the fractional D-branes that contains the contributions from the twisted sector of the ${\Bbb Z}_2$ orbifolding. We show that the cylinder partition functions for these fractional branes do not vanish, as in the cases of ordinary non-BPS D-branes. This aspect is in a sharp contrast with the bulk-type branes studied in arXiv:1704.05262[hep-th]. We then discuss the extensions of models by including the discrete torsion depending on the spin structures, and investigate whether we obtain the vanishing self-overlaps associated to the fractional branes. The existence/absence of bose-fermi cancellations both in the closed and open string spectra as well as the massless spectra in the twisted sectors crucially depend on the discrete torsion. We find that some choices of the torsion indeed realize the vanishing self-overlaps for the fractional branes, with keeping the vanishing torus partition function intact.
The non-perturbative nilpotent exact BRST symmetry of the Gribov-Zwanziger action in the Landau gauge constructed in [ arXiv:1506.06995 [hep-th]] is generalized to the case of Euclidean Yang-Mills theories quantized in the maximal Abelian gauge. The resulting diagonal gluon propagator is evaluating in dimensions D=4,3,2. In D=4,3 a decoupling type behavior is found in the infrared region, while in D=2 a scaling type behavior emerges.
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.
We study a certain class of nonextremal D1D5 geometries and their ergoregion emission. Using a detailed CFT computation and the formalism developed in arXiv:0906.2015 [hep-th], we compute the full spectrum and rate of emission from the geometries and find exact agreement with the gravity answer. Previously, only part of the spectrum had been reproduced using a CFT description. We close with a discussion of the context and significance of the calculation.
One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various non-perturbative effects. These include gaugino condensation and instantonic contributions to the superpotential.
We modify a recently proposed heterotic model hep-th/0703210, giving three net-generations of standard model fermions, to get rid of an additional U(1) factor in the gauge group. The method employs a stable SU(5) bundle on a Calabi-Yau threefold admitting a free involution. The bundle has to be built as a deformation of the direct sum of a stable SU(4) bundle and the trivial line bundle.
The original paper (hep-th/9209020) contains an early example of gauge mediated supersymmetry breaking motivated by string model building. In this erratum we point out an important misprint in the abstract of the published version (Phys. Lett. B295 (1992) 219) which may confuse the reader. We also correct the computation of scalar masses and the numerical examples. Qualitative results remain the same.
The purpose of this paper is to introduce and study a q-analogue of the holonomic system of differential equations associated to the Belavin's classical r-matrix (elliptic r-matrix equations), or, equivalently, to define an elliptic deformation of the quantum Knizhnik-Zamolodchikov equations of Frenkel and Reshetikhin. In hep-th 9303018, it was shown that solutions of the elliptic r-matrix equations admit a representation as traces of products of intertwining operators between certain modules over affine sl(N). In this paper, this construction is generalized to quantum affine sl(N). The main object of study in the paper is a family of meromorphic matrix functions of n complex variables z_1,...,z_n and three additional parameters p,q,s -- (modified) traces of products of intertwiners between modules over quantum affine sl(N). They are a new class of transcendental functions which can be degenerated into many interesting special functions -- hypergeometric and q-hypergeometric functions, elliptic and modular functions, transcendental functions of an elliptic curve, vector-valued modular forms, solutions of the Bethe ansatz equations etc. The main result of the paper states that these functions satisfy two holonomic systems of difference equations -- the first one has shift parameter p and elliptic modulus s, and the second one has shift parameter s and elliptic modulus p. The paper also contains a short proof of the quantum KZ equations.
The probability distribution functions (PDFs) of the circulation of velocity in three-dimensional decaying isotropic turbulence are examined using the database of numerical simulation based on the spectral method. It is shown that the standard deviation increases nearly as A 2/3 where A is the area of the loop. The PDFs change from exponential to Gaussian as the size increases. The former agrees well with the prediction by Migdal (1993, hep-th/9303130), although the latter deviates from it. A modification is proposed to explain the Gaussian distribution with the A 2/3 dependence.
Recently, Ivanov and Volovich (hep-th/9912242) claimed that the perturbation of $h_{\mu\nu}$ with nonvanishing transverse components $h_{5\mu}$ is not localized on the brane because $h_{\mu\nu}$ depends on the fifth coordinate $z$ linearly. Consequently, it may indicate that the effective theory is unstable. However, we point out that such linear dependence on $z$ can be {\it gauged away}. Hence the solution does not belong to the physical one. Therefore, even if one includes $h_{5\mu}$, Randall and Sundrum's argument for the localized gravity on the brane remains correct.
As shown by Hashimoto and Itzhaki in hep-th/9911057, the perturbative degrees of freedom of a non-commutative Yang-Mills theory (NCYM) on a torus are quasi-local only in a finite energy range. Outside that range one may resort to a Morita equivalent (or T-dual) description appropriate for that energy. In this note, we study NCYM on a non-commutative torus with an irrational deformation parameter θ. In that case, an infinite tower of dual descriptions is generically needed in order to describe the UV regime. We construct a hierarchy of dual descriptions in terms of the continued fraction approximations of θ. We encounter different descriptions depending on the level of the irrationality of θ and the amount of non-locality tolerated. The behavior turns out to be isomorphic to that found for the phase structure of the four-dimensional Villain N lattice gauge theories, which we revisit as a warm-up. At large 't Hooft coupling, using the AdS/CFT correspondance, we find that there are domains of the radial coordinate U where no T-dual description makes the derivative expansion converge. The radial direction obtains multifractal characteristics near the boundary of AdS.
Abstract This is a summary of the work in the author's recent paper with this title written with Jerome Gauntlett, George Papadopoulos and Paul Townsend, hep-th/97022012. We showed how to construct hyper-Kahler 8-metrics in terms of arrangements of three-dimensional hyperplanes in six-dimensional euclidean space. The slopes of the planes define two relatively prime intgers (p,q). Under reduction to ten dimensions and T-duality we get a geometric picture of the action of SL(2, Z ) on the (NS ⊗ NS, qR ⊗ R) 5-branes of type IIB string theory. Configurations are exhibited with 3 16 ' th SUSY.
This is a reply to a recent comment (hep-th/9910158) by Park and Ho on a paper (hep-th/9812013) that describes a derivation of black hole entropy from horizon conformal field theory. The criticism of Park and Ho is partially correct - the original paper did not give the complete surface term in the Hamiltonian - but it does not affect the conclusions, which have been checked using a somewhat different, manifestly covariant formalism (gr-qc/9906126).
These notes describe how perturbative on-shell and off-shell string amplitudes can be computed using string field theory. Computational methods for approximating arbitrary amplitudes are discussed, and compared with standard world-sheet methods for computing on-shell amplitudes. These lecture notes are not self-contained; they contain the material from W. Taylor's TASI 2003 lectures not covered in the recently published ``TASI 2001'' notes {\tt hep-th/0311017} by Taylor and Zwiebach, and should be read as a supplement to those notes.