arXiv subjects
Publications and source records attributed to Seok Kim.
We calculate and study the general superconformal index for the 6d U(N) (2,0) theory with four chemical potentials, from the indices of gauge theories on CP^2 x R. Our index agrees with the large N supergravity index on AdS_7 x S^4 at low energies, and also yields the negative 'Casimir energy' with an N^3 scaling which was recently calculated from a QFT on S^5. Our approach also suggests a systematic study of the (1,0) superconformal indices.
We use the 5-sphere partition functions of supersymmetric Yang-Mills theories to explore the (2,0) superconformal theory on S^5 x S^1. The 5d theories can be regarded as Scherk-Schwarz reductions of the 6d theory along the circle. In a special limit, the perturbative partition function takes the form of the Chern-Simons partition function on S^3. With a simple non-perturbative completion, it becomes a 6d index which captures the degeneracy of a sector of BPS states as well as the index version of the vacuum Casimir energy. The Casimir energy exhibits the N^3 scaling at large N. The large N index for U(N) gauge group also completely agrees with the supergravity index on AdS_7 x S^4.
We calculate the partition functions of supersymmetric gauge theories on S^5, which acquire non-perturbative contributions from instanton loops wrapping its Hopf fiber. The instantons on the CP^2 base equivariantly localize to 3 fixed points of SU(3) Cartans. Using our results, we study the index of the 6d (2,0) theory. We first study the partition functions of maximal SYM with AD(E) gauge groups, which agree with the gravity dual indices on AdS_7 in the large N limits. We also show that the most general partition function of the Abelian theory agrees with the index for a free 6d tensor supermultiplet. We explain possible ambiguities in our 5d approach, role of maximal SUSY, and the Wilson loops on S^5 dual to M2-brane Wilson surfaces in AdS_7.
We study a supersymmetric partition function of topological vortices in 3d N=4,3 gauge theories on R^2 x S^1, and use it to explore Seiberg-like dualities with Fayet-Iliopoulos deformations. We provide a detailed support of these dualities and also clarify the roles of vortices. The N=4 partition function confirms the proposed Seiberg duality and suggests nontrivial extensions, presumably at novel IR fixed points with enhanced symmetries. The N=3 theories with nonzero Chern-Simons term also have non-topological vortices in the partially broken phases, which are essential for the Seiberg duality invariance of the spectrum. We use our partition function to confirm some properties of non-topological vortices via Seiberg duality in a simple case.
We investigate the superconformal index and the partition function for the chiral-like Chern-Simons-matter theory proposed for M2-branes probing the cones over $M^{3,2}$ and find perfect agreements with the gravity index and the gravitational free energy.
Instantons and W-bosons in 5d maximally supersymmetric Yang-Mills theory arise from a circle compactification of the 6d (2,0) theory as Kaluza-Klein modes and winding self-dual strings, respectively. We study an index which counts BPS instantons with electric charges in Coulomb and symmetric phases. We first prove the existence of unique threshold bound state of (noncommutative) U(1) instantons for any instanton number, and also show that charged instantons in the Coulomb phase correctly give the degeneracy of SU(2) self-dual strings. By studying SU(N) self-dual strings in the Coulomb phase, we find novel momentum-carrying degrees on the worldsheet. The total number of these degrees equals the anomaly coefficient of SU(N) (2,0) theory. We finally show that our index can be used to study the symmetric phase of this theory, and provide an interpretation as the superconformal index of the sigma model on instanton moduli space.
We study an M-theory solution for the holographic flow of AdS4 times Sasaki-Einstein 7-manifolds with skew-whiffing, perturbed by a mass operator. The infrared solution contains the 5 dimensional Schrodinger geometry after considering the gravity dual of the standard non-relativistic limit of relativistic field theories. The mass deformation of the field theory is discussed in detail for the case with 7 manifold being a round sphere.
We investigate the superconformal indices for the Chern-Simons-matter theories proposed for M2-branes probing the cones over N^{010}/Z_k, Q^{111}, M^{32} with N=2,3 supersymmetries and compare them with the corresponding dual gravity indices. For N^{010}, we find perfect agreements. In addition, for N^{010}/Z_k, we also find an agreement with the gravity index including the contributions from two types of D6-branes wrapping RP^3. For Q^{111}, we find that the model obtained by adding fundamental flavors to the N=6 theory has the right structure to be the correct model. For M^{32}, we find the matching with the gravity index modulo contributions from peculiar saddle points.
We find and study the gravity duals of the supersymmetric vacua of N=6 mass-deformed Chern-Simons-matter theory for M2-branes. The classical solution extends that of Lin, Lunin and Maldacena by introducing a Z_k quotient and discrete torsions. The gravity vacua perfectly map to the recently identified supersymmetric field theory vacua. We calculate the masses of BPS charged particles in the weakly coupled field theory, which agree with the classical open membrane analysis when both calculations are reliable. We also comment on how non-relativistic conformal symmetry is realized in our gravity duals in a non-geometric way.
We calculate the superconformal index for N=6 Chern-Simons-matter theory with gauge group U(N) X U(N) at arbitrary allowed value of the Chern-Simons level k. The calculation is based on localization of the path integral for the index. Our index counts supersymmetric gauge invariant operators containing inclusions of magnetic monopole operators, where latter operators create magnetic fluxes on 2-sphere. Through analytic and numerical calculations in various sectors, we show that our result perfectly agrees with the index over supersymmetric gravitons in AdS_4 X S^7/Z_k in the large N limit. Monopole operators in nontrivial representations of U(N) X U(N) play important roles. We also comment on possible applications of our methods to other superconformal Chern-Simons theories.
We construct classical solutions for magnetic monopole operators in N=6 superconformal Chern-Simons-matter theories. In particular, we explicitly find solutions with unequal magnetic flux contents in the two U(N) gauge groups, whose existence has been known only indirectly. We also study the ground state degeneracies of the U(2) x U(2) monopoles by quantizing the moduli of the solution.
We calculate the superconformal Witten index for the Chern-Simons-matter theory which was proposed to describe multiple M2-branes on $C^2 X C^2/Z_k$. We consider a variant of this model, which exhibits explicit N=3 supersymmetry and has the advantage of not having an exotic branch of the moduli space. At $k=1$, we compare the index with that from the proposed gravity dual and find a disagreement.
We count the supersymmetric vacua of mass-deformed N=6 U(N)xU(N) Chern-Simons-matter theory by calculating the Witten index. When the Chern-Simons level k is 1, our result perfectly agrees with that from the gravity dual, given by partitions of N. For general k, our index generalizes partitions of N, including additional degrees. We also comment on non-relativistic superconformal theories constructed from this model.
We study local operators of U(N)xU(N) N=6 Chern-Simons-matter theory including a class of magnetic monopole operators. To take into account the interaction of monopoles and basic fields for large Chern-Simons level k, we consider the appropriate perturbation theory in 1/k which reliably describes small excitations around protected chiral operators. We also compute the superconformal index with some simple monopole operators and show that it agrees with the recent result obtained from localization. For this agreement, it is crucial that excitations of gauge fields and some matter scalars mix, which is described classically by odd dimensional self-duality like equations.
We construct consistent Kaluza--Klein reductions of D=11 supergravity to four dimensions using an arbitrary seven-dimensional Sasaki--Einstein manifold. At the level of bosonic fields, we extend the known reduction, which leads to minimal N=2 gauged supergravity, to also include a multiplet of massive fields, containing the breathing mode of the Sasaki--Einstein space, and still consistent with N=2 supersymmetry. In the context of flux compactifications, the Sasaki--Einstein reductions are generalizations of type IIA SU(3)-structure reductions which include both metric and form-field flux and lead to a massive universal tensor multiplet. We carry out a similar analysis for an arbitrary weak G_2 manifold leading to an N=1 supergravity with massive fields. The straightforward extension of our results to the case of the seven-sphere would imply that there is a four-dimensional Lagrangian with N=8 supersymmetry containing both massless and massive spin two fields. We use our results to construct solutions of M-theory with non-relativistic conformal symmetry.
We consider the BPS dyonic instantons in the 5-dim supersymmetric Yang-Mills Chern-Simons theories. Its field theoretic structures and the moduli space dynamics in term of the ADHM data have been explored in detail. We find that the field theoretic Chern-Simons term leads to an effective magnetic field on instanton moduli space.
We formulate the problem of counting 1/16 BPS states of N = 4 Yang Mills theory as the enumeration of the local cohomology of an operator acting on holomorphic fields on C^2. We study aspects of the enumeration of this cohomology at finite N, especially for operators constructed only out of products of covariant derivatives of scalar fields, and compare our results to the states obtained from the quantization of giant gravitons and dual giants. We physically interpret the holomorphic fields that enter our conditions for supersymmetry semi-classically by deriving a set of Bogomolnyi equations for 1/16-BPS bosonic field configurations in N = 4 Yang Mills theory on R^4 with reality properties and boundary conditions appropriate to radial quantization. An arbitrary solution to these equations in the free theory is parameterized by holomorphic data on C^2 and lifts to a nearby solution of the interacting Bogomolnyi equations only when the constraints equivalent to Q cohomology are obeyed.
We study the dynamics of a single M2-brane probing toric Calabi-Yau four-fold singularity in the context of the recently proposed M-theory crystal model of AdS4/CFT3 dual pairs. We obtain an effective abelian gauge theory in which the charges of the matter fields are given by the intersection numbers between loops and faces in the crystal. We argue that the probe theory captures certain aspects of the CFT3 even though the true M2-brane CFT is unlikely to be a usual gauge theory. In particular, the moduli space of vacua of the gauge theory coincides precisely with the Calabi-Yau singularity. Toric duality, partial resolution, and a possibility of new RG flows are also discussed.