118517951
The conformal manifold of Chern-Simons matter theories
We determine perturbatively the conformal manifold of $ \mathcal{N} = 2 $ Chern-Simons matter theories with the aim of checking in the three dimensional case the general prescription based on global symmetry breaking, recently introduced in [1–3]. We discuss in details few remarkable cases like the $ \mathcal{N} = 6 $ ABJM theory and its less supersymmetric generalizations with/without flavors. In all cases we find perfect agreement with the predictions of global symmetry breaking prescription. For unflavored theories the conformal manifold is a three dimensional compact surface. This feature is peculiar of three dimensions, as it has no direct analogue in four dimensional supersymmetric models.
119108513
The 1/2 BPS Wilson loop in ABJ(M) at two loops: the details
A bstractWe compute the expectation value of the 1/2 BPS circular Wilson loop operator in ABJ(M) theory at two loops in perturbation theory. Our result turns out to be in exact agreement with the weak coupling limit of the prediction coming from localization, including finite N contributions associated to non-planar diagrams. It also confirms the identification of the correct framing factor that connects framing-zero and framing one expressions, previously proposed. The evaluation of the 1/2 BPS operator is made technically difficult in comparison with other observables of ABJ(M) theory by the appearance of integrals involving the coupling between fermions and gauge fields, which are absent for instance in the 1/6 BPS case. We describe in detail how to analytically solve these integrals in dimensional regularization with dimensional reduction (DRED). By suitably performing the physical limit to three dimensions we clarify the role played by short distance divergences on the final result and the mechanism of their cancellation.
119117490
Nonplanarity through unitarity in the ABJM theory
We use unitarity techniques to compute the two-loop non-planar corrections to the Sudakov form factor and the four-point amplitude in ABJM theory. We start by reconstructing non-planar integrals from two-particle cuts in three dimensions. This causes ambiguities, due to the one-loop four-point amplitude being subleading in dimensional regularization. We provide a prescription to circumvent them and show that it leads to the correct results, as checked against the recent Feynman diagram computation. For the amplitude we point out an alternative basis of integrals, including a non-planar double-box with a numerator inspired by color-kinematics duality. We reproduce the result using a combination thereof with the coefficients fixed by generalized unitarity. For BLG theory we propose that this gives the form of the amplitude satisfying color-kinematics duality. Finally, we compute the complete two-loop amplitude of three-dimensional N = 8 SYM, and the corresponding four-point amplitude in N = 16 supergravity as a double copy.
54173371
One loop amplitudes in ABJM
A bstractFor three dimensional $ \mathcal{N} = 6 $ superconformal field theories we compute oneloop scattering amplitudes for any number of external particles. We focus on a particular subsector of $ \mathcal{N} = 2 $ invariant superamplitudes for which the ordinary perturbative evaluation becomes very easy. The result we obtain is in general non-vanishing. For six external particles our findings are sufficient for determining the complete expression of the $ \mathcal{N} = 6 $ superamplitude at this order. We discuss the symmetries of the result and its anomalous variation under superconformal generators.
123488833
Scattering amplitudes in three-dimensional superconformal field theory
Recent progress in computation of loop amplitudes in three-dimensional superconformal models is reviewed.
56038769
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis
A bstractWe study a family of circular BPS Wilson loops in $ \mathcal{N} $ = 6 super Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar and fermionic couplings depend on two deformation parameters and these operators can be considered as the ABJ(M) counterpart of the DGRT latitudes defined in $ \mathcal{N} $ = 4 SYM. We perform a complete two-loop analysis of their vacuum expectation value, discuss the appearance of framing-like phases and propose a general relation with cohomologically equivalent bosonic operators. We make an all-loop proposal for computing the Bremsstrahlung function associated to the 1/2-BPS cusp in terms of these generalized Wilson loops. When applied to our two-loop result it reproduces the known expression. Finally, we comment on the generalization of this proposal to the bosonic 1/6-BPS case.
119438273
Instantons and Supersymmetry
The role of instantons in describing non-perturbative aspects of globally supersymmetric gauge theories is reviewed. The cases of theories with N = 1, N = 2 and N = 4 supersymmetry are discussed. Special attention is devoted to the intriguing relation between instanton solutions in field theory and branes in string theory.
10399156
D-brane instantons on the T**6 / Z(3) orientifold
We give a detailed microscopic derivation of gauge and stringy instanton
generated superpotentials for gauge theories living on D3-branes at
Z_3-orientifold singularities. Gauge instantons are generated by D(-1)-branes
and lead to Affleck, Dine and Seiberg (ADS) like superpotentials in the
effective N=1 gauge theories with three generations of bifundamental and
anti/symmetric matter. Stringy instanton effects are generated by Euclidean
ED3-branes wrapping four-cycles on T^6/\Z_3. They give rise to Majorana masses
in one case and non-renormalizable superpotentials for the other cases. Finally
we determine the conditions under which ADS like superpotentials are generated
in N=1 gauge theories with adjoints, fundamentals, symmetric and antisymmetric
chiral matter.
16881657
(Unoriented) T-folds with few T's
We use the combined action of 2-chiral reflections (T-dualities) and shifts to build = 1,2 supersymmetric four-dimensional string compactifications with few moduli. In particular, we consider 24 asymmetric orbifolds of Type IIB on the maximal torus of SO(12) that mimic = 2 Calabi-Yau compactifications with small ``effective'' Hodge numbers starting from (h11,h21) = (1,1). We analyze possible unoriented projections, providing Type I examples with or without open strings. = 1 oriented asymmetric shift-orbifolds of Type IIB with few chiral multiplets are also presented.
17605666
Comments on orientifolds without vector structure
We revisit type I compactifications with a Spin(32)/Z2 gauge bundle that admits no vector structure. We elucidate the relation of this Z2 obstruction to discrete B- field flux and to 't Hooft flux and clarify some subtleties in the T-duality transformation to type IIA intersecting D-brane models. We reexamine the earliest 3-generation GUT model on magnetized D-branes and show its consistency when a discrete B-flux is switched on. We further generalize partially known results for toroidal models to type I compactifications without vector structure and their mirror dual type IIA orientifolds on genuine Calabi-Yau manifolds. We illustrate this by working out the example of the quintic in some detail.
14845820
Type I superstrings without D-branes
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