Engineering Papers⌕ Search

Engineering topics

Song, Jaewon

Publications and source records attributed to Song, Jaewon.

14 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Infinitely many 4D N = 1 SCFTs with a = c

Here, we study a rich set of four-dimensional N = 1 superconformal field theories (SCFTs) with both central charges identical: a = c. We construct them via the diagonal N = 1 gauging of the flavor symmetry G of a collection of N = 2 Argyres–Douglas theories of type D p (G), with or without additional adjoint chiral multiplets. In this way, we construct infinitely many theories that flow to interacting SCFTs with a = c in the infrared. Lastly, we briefly highlight the features of the SCFTs without a = c that arise from generalizing this construction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Four-dimensional lens space index from two-dimensional chiral algebra

We study the supersymmetric partition function on S 1 × L (r, 1), or the lens space index of four-dimensional N = 2 superconformal field theories and their connection to two-dimensional chiral algebras. We primarily focus on free theories as well as ArgyresDouglas theories of type ( A 1 , A k ) and ( A 1 , D k ). We observe that in specific limits, the lens space index is reproduced in terms of the (refined) character of an appropriately twisted module of the associated two-dimensional chiral algebra or a generalized vertex operator algebra. In conclusion the particular twisted module is determined by the choice of discrete holonomies for the flavor symmetry in four-dimensions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Vertex operator algebras of Argyres-Douglas theories from M5-branes

We study aspects of the vertex operator algebra (VOA) corresponding to Argyres-Douglas (AD) theories engineered using the 6d N = ( 2 , &#xA0; 0 ) theory of type J on a punctured sphere. We denote the AD theories as (J b [k], Y), where J b [k] and Y represent an irregular and a regular singularity respectively. We restrict to the ‘minimal’ case where J b [k] has no associated mass parameters, and the theory does not admit any exactly marginal deformations. The VOA corresponding to the AD theory is conjectured to be the W-algebra W k 2 d ( J , &#xA0; Y &#xA0; ) , where k 2 d = &#x2212;<!-- - --> h + b b + k with h being the dual Coxeter number of J. We verify this conjecture by showing that the Schur index of the AD theory is identical to the vacuum character of the corresponding VOA, and the Hall-Littlewood index computes the Hilbert series of the Higgs branch. We also find that the Schur and Hall-Littlewood index for the AD theory can be written in a simple closed form for b = h. We also test the conjecture that the associated variety of such VOA is identical to the Higgs branch. The M5-brane construction of these theories and the corresponding TQFT structure of the index play a crucial role in our computations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Superconformal index, BPS monodromy and chiral algebras

We show that specializations of the 4d N = 2 superconformal index labeled by an integer N is given by Tr M N where M is the Kontsevich-Soibelman monodromy operator for BPS states on the Coulomb branch. We provide evidence that the states enumerated by these limits of the index lead to a family of 2d chiral algebras A N . This generalizes the recent results for the N = –1 case which corresponds to the Schur limit of the superconformal index. We show that this specialization of the index leads to the same integrand as that of the elliptic genus of compactification of the superconformal theory on S 2 × T 2 where we turn on 1/2 N units of U(1) r flux on S 2 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Macdonald index and chiral algebra

For any 4dN = 2 SCFT, there is a subsector described by a 2d chiral algebra. The vacuum character of the chiral algebra reproduces the Schur index of the corresponding 4d theory. The Macdonald index counts the same set of operators as the Schur index, but the former has one more fugacity than the latter. Here, we conjecture a prescription to obtain the Macdonald index from the chiral algebra. The vacuum module admits a filtration, from which we construct an associated graded vector space. From this grading, we conjecture a notion of refined character for the vacuum module of a chiral algebra, which reproduces the Macdonald index. We test this prescription for the Argyres-Douglas theories of type (A 1 , A 2n ) and (A 1 , D 2n+1 ) where the chiral algebras are given by Virasoro and $ˆ\atop{su}$(2) affine Kac-Moody algebra. When the chiral algebra has more than one family of generators, our prescription requires a knowledge of the generators from the 4d.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

New dualities and misleading anomaly matchings from outer-automorphism twists

We study four-dimensional N=1, 2 superconformal theories in class S obtained by compactifying the 6d N=(2, 0) theory on a Riemann surface C with outer-automorphism twist lines. From the pair-of-pants decompositions of C, we find various dual descriptions for the same theory having distinct gauge groups. We show that the various configurations of the twist line give rise to dual descriptions for the identical theory. We compute the ’t Hooft anomaly coefficients and the superconformal indices to test dualities. Surprisingly, we find that the class S theories with twist lines wrapping 1-cycles of C have the identical ’t Hooft anomalies as the ones without the twist line, whereas the superconformal indices differ. As a result, this provides a large set of examples where the anomaly matching is insufficient to test dualities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

$ \mathcal{N}=1 $ deformations and RG flows of $ \mathcal{N}=2 $ SCFTs

Here, we study certain $ \mathcal{N}=1 $ preserving deformations of four-dimensional $ \mathcal{N}=2 $ superconformal field theories (SCFTs) with non-abelian flavor symmetry. The deformation is described by adding an $ \mathcal{N}=1 $ chiral multiplet transforming in the adjoint representation of the flavor symmetry with a superpotential coupling, and giving a nilpotent vacuum expectation value to the chiral multiplet which breaks the flavor symmetry. This triggers a renormalization group flow to an infrared SCFT. Remarkably, we find classes of theories flow to enhanced $ \mathcal{N}=2 $ supersymmetric fixed points in the infrared under the deformation. They include generalized Argyres-Douglas theories and rank-one SCFTs with non-abelian flavor symmetries. Most notably, we find renormalization group flows from the deformed conformal SQCDs to the ( A 1 ,A n ) Argyres-Douglas theories. From these "Lagrangian descriptions," we compute the full superconformal indices of the ( A 1 ,A n ) theories and find agreements with the previous results. Furthermore, we study the cases, including the T N and R 0,N theories of class S and some of rank-one SCFTs, where the deformation gives genuine $ \mathcal{N}=1 $ fixed points.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

N = 1 Deformations and RG flows of N = 2 SCFTs, part II: non-principal deformations

We continue to investigate the N = 1 deformations of four-dimensional N = 2 superconformal field theories (SCFTs) labeled by a nilpotent element of the flavor symmetry [1]. This triggers a renormalization group (RG) flow to an N = 1 SCFT. We systematically analyze all possible deformations of this type for certain classes of N = 2 SCFTs: conformal SQCDs, generalized Argyres-Douglas theories and the E 6 SCFT. We find a number of examples where the amount of supersymmetry gets enhanced to N = 2 at the end point of the RG flow. Most notably, we find that the SU(N) and Sp(N) conformal SQCDs can be deformed to flow to the Argyres-Douglas (AD) theories of type (A 1 ,D 2 N-1 ) and (A 1 ,D 2 N ) respectively. This RG flow therefore allows us to compute the full superconformal index of the (A 1 ,D N ) class of AD theories. Moreover, we find an infrared duality between N = 1 theories where the fixed point is described by an N = 2 AD theory. We observe that the classes of examples that exhibit supersymmetry enhancement saturate certain bounds for the central charges implied by the associated two-dimensional chiral algebra.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

(0,4) dualities

We study a class of two-dimensional N = (0; 4) quiver gauge theories that flow to superconformal field theories. We find dualities for the superconformal field theories similar to the 4d N = 2 theories of class S, labelled by a Riemann surface C. The dual descriptions arise from various pair-of-pants decompositions, that involve an analog of the T N theory. Especially, we find the superconformal indices of such theories can be written in terms of a topological field theory on C. In conclusion, we interpret this class of SCFTs as the ones coming from compactifying 6d N = (2; 0) theory on CP 1 x C. Moreover, some new dualities of (0; 2) and (2; 2) theories are also discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Superconformal indices of generalized Argyres-Douglas theories from 2d TQFT

We present superconformal indices of 4d N = 2 class S theories with certain irregular punctures called type I k,N . This class of theories include generalized Argyres-Douglas theories of type (A k-1 , A N-1 ) and more. We conjecture the superconformal indices in certain simplifi ed limits based on the TQFT structure of the class S theories by writing an expression for the wave function corresponding to the puncture I k,N . We write the Schur limit of the wave function when k and N are coprime. When k = 2, we also conjecture a closed-form expression for the Hall-Littlewood index and the Macdonald index for odd N. From the index, we argue that certain short-multiplet which can appear in the OPE of the stress-energy tensor is absent in the (A 1 ,A 2n ) theory. In addition, we discuss the mixed Schur indices for the N = 1 class S theories with irregular punctures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Infinitely many $ \mathcal{N}=1 $ dualities from m + 1 - m = 1

We discuss two infinite classes of 4d supersymmetric theories, T N (m) and U$(m)\atop{N}$, labelled by an arbitrary non-negative integer, m. The T N (m) theory arises from the 6d, A N-1 type N=(2,0) theory reduced on a 3-punctured sphere, with normal bundle given by line bundles of degree (m + 1, -m); the m = 0 case is the N=2 supersymmetric T N theory. The novelty is the negative-degree line bundle. The U$(m)\atop{N}$ theories likewise arise from the 6d N=(2,0) theory on a 4-punctured sphere, and can be regarded as gluing together two (partially Higgsed) T N (m) theories. The T N (m) and U$(m)\atop{N}$ theories can be represented, in various duality frames, as quiver gauge theories, built from T N components via gauging and nilpotent Higgsing. We analyze the RG flow of the U($(m)\atop{N}$ theories, and find that, for all integer m > 0, they end up at the same IR SCFT as SU(N) SQCD with 2N flavors and quartic superpotential. The U$(m)\atop{N}$ theories can thus be regarded as an infinite set of UV completions, dual to SQCD with N f = 2N c . The U$(m)\atop{N}$ duals have different duality frame quiver representations, with 2m + 1 gauge nodes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Quiver tails and $\mathcal{N}=1 $ SCFTs from M5-branes

We study a class of four-dimensional N = 1 superconformal field theories obtained by wrapping M5-branes on a Riemann surface with punctures. We identify fourdimensional UV descriptions of the SCFTs corresponding to curves with a class of punctures. The quiver tails appearing in these UV descriptions differ significantly from their N = 2 counterpart. We find a new type of object that we call the ‘Fan’. We show how to construct new N = 1 superconformal theories using the Fan. Various dual descriptions for these SCFTs can be identified with different colored pair-of-pants decompositions. For example, we find an N = 1 analog of Argyres-Seiberg duality for the SU(N) SQCD with 2N flavors. Finally, we also compute anomaly coefficients and superconformal indices for these theories and show that they are invariant under dualities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗