arXiv subjects

Daniel Krefl

Publications and source records attributed to Daniel Krefl.

28 records · Page 2Linked to original sources

arXiv2010

Extended Holomorphic Anomaly in Gauge Theory

The partition function of an N=2 gauge theory in the Omega-background satisfies, for generic value of the parameter beta=-eps_1/eps_2, the, in general extended, but otherwise beta-independent, holomorphic anomaly equation of special geometry. Modularity together with the (beta-dependent) gap structure at the various singular loci in the moduli space completely fixes the holomorphic ambiguity, also when the extension is non-trivial. In some cases, the theory at the orbifold radius, corresponding to beta=2, can be identified with an "orientifold" of the theory at beta=1. The various connections give hints for embedding the structure into the topological string.

hep-th↗

arXiv2010

Wall Crossing Phenomenology of Orientifolds

We initiate the study of wall crossing phenomena in orientifolds of local toric Calabi-Yau 3-folds from a topological string perspective. For this purpose, we define a notion of real Donaldson-Thomas partition function at the large volume, orbifold and non-commutative point in Kaehler moduli space. As a byproduct, we refine the constant map contribution to the partition function of the real topological string on a local toric background. We conjecture the general relation between the real large volume and real non-commutative/orbifold Donaldson-Thomas partition function of orientifolds of local toric Calabi-Yau 3-folds without compact divisors. The conjectured relation is confirmed at hand of the conifold and local A_n singularity, for which we explicitly derive the real non-commutative/orbifold Donaldson-Thomas partition function combinatorially.

hep-th↗

arXiv2009

The Real Topological Vertex at Work

We develop the real vertex formalism for the computation of the topological string partition function with D-branes and O-planes at the fixed point locus of an anti-holomorphic involution acting non-trivially on the toric diagram of any local toric Calabi-Yau manifold. Our results cover in particular the real vertex with non-trivial fixed leg. We give a careful derivation of the relevant ingredients using duality with Chern-Simons theory on orbifolds. We show that the real vertex can also be interpreted in terms of a statistical model of symmetric crystal melting. Using this latter connection, we also assess the constant map contribution in Calabi-Yau orientifold models. We find that there are no perturbative contributions beyond one-loop, but a non-trivial sum over non-perturbative sectors, which we compare with the non-perturbative contribution to the closed string expansion.

hep-th↗

arXiv2009

The Real Topological String on a local Calabi-Yau

We study the topological string on local P2 with O-plane and D-brane at its real locus, using three complementary techniques. In the A-model, we refine localization on the moduli space of maps with respect to the torus action preserved by the anti-holomorphic involution. This leads to a computation of open and unoriented Gromov-Witten invariants that can be applied to any toric Calabi-Yau with involution. We then show that the full topological string amplitudes can be reproduced within the topological vertex formalism. We obtain the real topological vertex with trivial fixed leg. Finally, we verify that the same results derive in the B-model from the extended holomorphic anomaly equation, together with appropriate boundary conditions. The expansion at the conifold exhibits a gap structure that belongs to a so far unidentified universality class.

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arXiv2008

A gauge theory analog of some "stringy" D-instantons

We argue that one can see a specific class of "stringy" D-instantons in the underlying 4D gauge theory as the UV completion of an ordinary gauge instanton of a completely broken gauge group corresponding to the "empty" cycle the D-instanton is located on. In this sense, the D-instanton induced non-perturbative superpotential can be qualitatively inferred directly from pure field-theory considerations.

hep-th↗

arXiv2008

Real Mirror Symmetry for One-parameter Hypersurfaces

We study open string mirror symmetry for one-parameter Calabi-Yau hypersurfaces in weighted projective space. We identify mirror pairs of D-brane configurations, derive the corresponding inhomogeneous Picard-Fuchs equations, and solve for the domainwall tensions as analytic functions over moduli space. Our calculations exemplify several features that had not been seen in previous work on the quintic or local Calabi-Yau manifolds. We comment on the calculation of loop amplitudes.

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arXiv2008

Brane Tilings for Orientifolds

We give an elementary introduction to the recent derivation of the effective low-energy gauge theories of D3-branes probing orientifolds of toric Calabi-Yau 3-fold singularities via brane tiling techniques.

hep-th↗

arXiv2007

Dimers and Orientifolds

We introduce new techniques based on brane tilings to investigate D3-branes probing orientifolds of toric Calabi-Yau singularities. With these new tools, one can write down many orientifold models and derive the resulting low-energy gauge theories living on the D-branes. Using the set of ideas in this paper one recovers essentially all orientifolded theories known so far. Furthermore, new orientifolds of non-orbifold toric singularities are obtained. The possible applications of the tools presented in this paper are diverse. One particular application is the construction of models which feature dynamical supersymmetry breaking as well as the computation of D-instanton induced superpotential terms.

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arXiv2006

Gaugino Condensates and D-terms from D7-branes

We investigate, at the microscopic level, the compatibility between D-term potentials from world-volume fluxes on D7-branes and non-perturbative superpotentials arising from gaugino condensation on a different stack of D7-branes. This is motivated by attempts to construct metastable de Sitter vacua in type IIB string theory via D-term uplifts. We find a condition under which the Kaehler modulus, T, of a Calabi-Yau 4-cycle gets charged under the anomalous U(1) on the branes with flux. If in addition this 4-cycle is wrapped by a stack of D7-branes on which gaugino condensation takes place, the question of U(1)-gauge invariance of the (T-dependent) non-perturbative superpotential arises. In this case an index theorem guarantees that strings, stretching between the two stacks, yield additional charged chiral fields which also appear in the superpotential from gaugino condensation. We check that the charges work out to make this superpotential gauge invariant, and we argue that the mechanism survives the inclusion of higher curvature corrections to the D7-brane action.

hep-th↗

arXiv2006

On supersymmetric Minkowski vacua in IIB orientifolds

Supersymmetric Minkowski vacua in IIB orientifold compactifications based on orbifolds with background fluxes and non-perturbative superpotentials are investigated. Especially, microscopic requirements and difficulties to obtain such vacua are discussed. We show that orbifold models with one and two complex structure moduli and supersymmetric 2-form flux can be successfully stabilized to such vacua. By taking additional gaugino condensation on fixed space-time filling D3-branes into account also models without complex structure can be consistently stabilized to Minkowski vacua.

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