arXiv subjects

Beatriz Gato-Rivera

Publications and source records attributed to Beatriz Gato-Rivera.

32 records · Page 2Linked to original sources

arXiv1999

Transmutations between Singular and Subsingular Vectors of the N=2 Superconformal Algebras

We present subsingular vectors of the N=2 superconformal algebras other than the ones which become singular in chiral Verma modules, reported recently by Gato-Rivera and Rosado. We show that two large classes of singular vectors of the Topological algebra become subsingular vectors of the Antiperiodic NS algebra under the topological untwistings. These classes consist of BRST- invariant singular vectors with relative charges $q=-2,-1$ and zero conformal weight, and no-label singular vectors with $q=0,-1$. In turn the resulting NS subsingular vectors are transformed by the spectral flows into subsingular and singular vectors of the Periodic R algebra. We write down these singular and subsingular vectors starting from the topological singular vectors at levels 1 and 2.

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arXiv1999

A Note concerning Subsingular Vectors and Embedding Diagrams of the N=2 Superconformal Algebras

Subsingular vectors of the N=2 superconformal algebras were discovered, and examples given, in 1996. Shortly afterwards Semikhatov and Tipunin claimed to have obtained a complete classification of the N=2 subsingular vectors in the paper `The Structure of Verma Modules over the N=2 Superconformal algebra', hep-th/9704111, published in CMP 195 (1998) 129. Surprisingly, the only explicit examples of N=2 subsingular vectors known at that time did not fit into their classification. All the results presented in that paper, including the classification of subsingular vectors, were based on the following assumptions: i) The authors claimed that there are only two different types of submodules in N=2 Verma modules, overlooking from the very beginning indecomposable `no-label' singular vectors, that had been discovered a few months before, and clearly do not fit into their two types of submodules, and ii) The authors claimed to have constructed `non-conventional' singular vectors with the property of generating the two types of submodules maximally, i.e. with no subsingular vectors left outside. In this note we prove that both assumptions are incorrect. These facts also affect profoundly the results presented in several other publications, especially the papers: `On the Equivalence of Affine sl(2) and N=2 ....', by Semikhatov, hep-th/9702074, `Embedding Diagrams of N=2 Verma Modules ....', by Semikhatov and Sirota, hep-th/9712102, and `All Singular Vectors of the N=2 ....', by Semikhatov and Tipunin, hep-th/9604176 (last revised version in September 98).

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arXiv1999

Singular dimensions of the N=2 superconformal algebras II: the twisted N=2 algebra

We introduce a suitable adapted ordering for the twisted N=2 superconformal algebra (i.e. with mixed boundary conditions for the fermionic fields). We show that the ordering kernels for complete Verma modules have two elements and the ordering kernels for G-closed Verma modules just one. Therefore, spaces of singular vectors may be two-dimensional for complete Verma modules whilst for G-closed Verma modules they can only be one-dimensional. We give all singular vectors for the levels 1/2, 1, and 3/2 for both complete Verma modules and G-closed Verma modules. We also give explicit examples of degenerate cases with two-dimensional singular vector spaces in complete Verma modules. General expressions are conjectured for the relevant terms of all (primitive) singular vectors, i.e. for the coefficients with respect to the ordering kernel. These expressions allow to identify all degenerate cases as well as all G-closed singular vectors. They also lead to the discovery of subsingular vectors for the twisted N=2 superconformal algebra. Explicit examples of these subsingular vectors are given for the levels 1/2, 1, and 3/2. Finally, the multiplication rules for singular vector operators are derived using the ordering kernel coefficients. This sets the basis for the analysis of the twisted N=2 embedding diagrams.

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arXiv1998

Singular dimensions of the N=2 superconformal algebras. I

Verma modules of superconfomal algebras can have singular vector spaces with dimensions greater than 1. Following a method developed for the Virasoro algebra by Kent, we introduce the concept of adapted orderings on superconformal algebras. We prove several general results on the ordering kernels associated to the adapted orderings and show that the size of an ordering kernel implies an upper limit for the dimension of a singular vector space. We apply this method to the topological N=2 algebra and obtain the maximal dimensions of the singular vector spaces in the topological Verma modules: 0, 1, 2 or 3 depending on the type of Verma module and the type of singular vector. As a consequence we prove the conjecture of Gato-Rivera and Rosado on the possible existing types of topological singular vectors (4 in chiral Verma modules and 29 in complete Verma modules). Interestingly, we have found two-dimensional spaces of singular vectors at level 1. Finally, by using the topological twists and the spectral flows, we also obtain the maximal dimensions of the singular vector spaces for the Neveu-Schwarz N=2 algebra (0, 1 or 2) and for the Ramond N=2 algebra (0, 1, 2 or 3).

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arXiv1998

Construction Formulae for Singular Vectors of the Topological N=2 Superconformal Algebra

The Topological N=2 Superconformal algebra has 29 different types of singular vectors (in complete Verma modules) distinguished by the relative U(1) charge and the BRST-invariance properties of the vector and of the primary on which it is built. Whereas one of these types only exists at level zero, the remaining 28 types exist for general levels and can be constructed already at level 1. In this paper we write down one-to-one mappings between 16 of these types of topological singular vectors and the singular vectors of the Antiperiodic NS algebra. As a result one obtains construction formulae for these 16 types of topological singular vectors using the construction formulae for the NS singular vectors due to Doerrzapf.

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arXiv1997

Families of Singular and Subsingular Vectors of the Topological N=2 Superconformal Algebra

We analyze several issues concerning the singular vectors of the Topological N=2 Superconformal algebra. First we investigate which types of singular vectors exist, regarding the relative U(1) charge and the BRST-invariance properties, finding four different types in chiral Verma modules and twenty-nine different types in complete Verma modules. Then we study the family structure of the singular vectors, every member of a family being mapped to any other member by a chain of simple transformations involving the spectral flows. The families of singular vectors in chiral Verma modules follow a unique pattern (four vectors) and contain subsingular vectors. We write down these families until level 3, identifying the subsingular vectors. The families of singular vectors in complete Verma modules follow infinitely many different patterns, grouped roughly in five main kinds. We present a particularly interesting thirty-eight-member family at levels 3, 4, 5, and 6, as well as the complete set of singular vectors at level 1 (twenty-eight different types). Finally we analyze the Dörrzapf conditions leading to two linearly independent singular vectors of the same type, at the same level in the same Verma module, and we write down four examples of those pairs of singular vectors, which belong to the same thirty-eight-member family.

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arXiv1997

Chiral Determinant Formulae and Subsingular Vectors for the N=2 Superconformal Algebras

We derive conjectures for the N=2 "chiral" determinant formulae of the Topological algebra, the Antiperiodic NS algebra, and the Periodic R algebra, corresponding to incomplete Verma modules built on chiral topological primaries, chiral and antichiral NS primaries, and Ramond ground states, respectively. Our method is based on the analysis of the singular vectors in chiral Verma modules and their spectral flow symmetries, together with some computer exploration and some consistency checks. In addition, and as a consequence, we uncover the existence of subsingular vectors in these algebras, giving examples (subsingular vectors are non-highest-weight null vectors which are not descendants of any highest-weight singular vectors).

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arXiv1997

The Even and the Odd Spectral Flows on the N=2 Superconformal Algebras

There are two different spectral flows on the N=2 superconformal algebras (four in the case of the Topological algebra). The usual spectral flow, first considered by Schwimmer and Seiberg, is an even transformation, whereas the spectral flow previously considered by the author and Rosado is an odd transformation. We show that the even spectral flow is generated by the odd spectral flow, and therefore only the latter is fundamental. We also analyze thoroughly the four ``topological'' spectral flows, writing two of them here for the first time. Whereas the even and the odd spectral flows have quasi-mirrored properties acting on the Antiperiodic or the Periodic algebras, the topological even and odd spectral flows have drastically different properties acting on the Topological algebra. The other two topological spectral flows have mixed even and odd properties. We show that the even and the even-odd topological spectral flows are generated by the odd and the odd-even topological spectral flows, and therefore only the latter are fundamental.

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arXiv1996

Interpretation of the Determinant Formulae for the Chiral Representations of the N=2 Superconformal Algebra

We show that the N=2 determinant formulae of the Aperiodic NS algebra and the Periodic R algebra can be applied directly to incomplete Verma modules built on chiral primary states and on Ramond ground states, respectively, provided one modifies the interpretation of the zeroes in an appropriate way. That is, the zeroes of the determinat formulae account for the highest weight singular states built on chiral primaries and on Ramond ground states, but the identification of the levels and relative U(1) charges of the singular states is different than for complete Verma modules. In particular, half of the zeroes of the quadratic vanishing surfaces $f^A_{r,s}=0$ and $f^P_{r,s}=0$ correspond to uncharged singular states, and the other half correspond to charged singular states. We derive the spectrum of singular states built on chiral primaries, including the singular states of the Twisted Topological algebra, and the spectrum of singular states built on the Ramond ground states. We also uncover the existence of non-highest weight singular states which are not secondary of any highest weight singular state.

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arXiv1995

The Other Spectral Flow

Recently we showed that the spectral flow acting on the N=2 twisted topological theories gives rise to a topological algebra automorphism. Here we point out that the untwisting of that automorphism leads to a spectral flow on the untwisted N=2 superconformal algebra which is different from the usual one. This "other" spectral flow does not interpolate between the chiral ring and the antichiral ring. In particular, it maps the chiral ring into the chiral ring and the antichiral ring into the antichiral ring. We discuss the similarities and differences between both spectral flows. We also analyze their action on null states.

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arXiv1995

Spectral Flows and Twisted Topological Theories

We analyze the action of the spectral flows on N=2 twisted topological theories. We show that they provide a useful mapping between the two twisted topological theories associated to a given N=2 superconformal theory. This mapping can also be viewed as a topological algebra automorphism. In particular null vectors are mapped into null vectors, considerably simplifying their computation. We give the level 2 results. Finally we discuss the spectral flow mapping in the case of the DDK and KM realizations of the topological algebra.

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arXiv1994

Topological Theories from Virasoro Constraints on the KP Hierarchy

A conformal field theory can be recovered, via the Kontsevich-Miwa transform, as a solution to the Virasoro constraints on the KP tau function. That theory, which we call KM CFT, consists of d \leq 1 matter plus a scalar and a dressing prescription: Δ= 0 for every primary field. By adding a spin-1 bc system the KM CFT provides a realization of the N=2 twisted topological algebra. The other twist of the corresponding untwisted N=2 superconformal theory is a DDK realization of the N=2 twisted topological algebra. Talk given by Beatriz Gato-Rivera at the "28th International Symposium on the Theory of Elementary Particles", Wendisch-Rietz (Germany), August 30 - September 3, 1994.

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arXiv1994

Topological Descendants: DDK and KM Realizations

The "minimal matter + scalar" system can be embedded into the twisted N=2 topological algebra in two ways: a la DDK or a la KM. Here we present some results concerning the topological descendants and their DDK and KM realizations. In particular, we prove four "no-ghost" theorems (two for null states) regarding the reduction of the topological descendants into secon- daries of the "minimal matter + scalar" conformal field theory. We write down the relevant expressions for the case of level 2 descendants.

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arXiv1994

Modular invariants and fusion rule automorphisms from Galois theory

We show that Galois theory of cyclotomic number fields provides a powerful tool to construct systematically integer-valued matrices commuting with the modular matrix S, as well as automorphisms of the fusion rules. Both of these prescriptions allow the construction of modular invariants and offer new insight in the structure of known exceptional invariants.

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