Physics Letters B 800 (2020) 135101

Contents lists available at ScienceDirect

Physics Letters B

www.elsevier.com/locate/physletb

On quiver W-algebras and defects from gauge origami

Peter Koroteev

Department of Mathematics, University of California Berkeley, 970 Evans Hall #3840, University of California, Berkeley, CA 94720-3840, the United States of America a r t i c l e i n f o a b s t r a c t

Article history: In this note, using Nekrasov’s gauge origami framework, we study two different versions of the BPS/CFT Received 12 August 2019 correspondence – first, the standard AGT duality and, second, the quiver W algebra construction which Received in revised form 23 October 2019 has been developed recently by Kimura and Pestun. The gauge origami enables us to work with both Accepted 11 November 2019 dualities simultaneously and find exact matchings between the parameters. In our main example of an Available online 14 November 2019 A-type quiver gauge theory, we show that the corresponding quiver qW-algebra and its representations Editor: N. Lambert are closely related to a large-n limit of spherical gln double affine Hecke algebra whose modules are described by partition functions of a defect quiver theory. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.

1. Introduction n →∞ this constraint disappears and the one obtains a complete (q)Virasoro algebra. The BPS/CFT correspondence [24]is an intriguing duality which Therefore, for type A quiver gauge theories in five dimensions, relates counting of BPS states in gauge theories with extended su- the Kimura-Pestun duality provides a spectral dual (also fiber-base persymmetry in various dimensions with conformal field theories dual or S-dual) version of the BPS/CFT to the standard (q)AGT re- and their symmetries, i.e. (q)vertex operator algebras (VOA)s. The lation. This can be understood from studying the brane picture for most well-studied example is the Alday-Gaiotto-Tachikawa (AGT) the corresponding gauge theories. We decide to work with 5d the- correspondence [1] which conjectures equalities between Liouville ories since K-theoretic Nekrasov functions are better behaved un- (Toda) conformal blocks and Nekrasov partition functions of the der the above-mentioned duality. Also [18]is naturally formulated dual 4d N = 2gauge theories with eight supercharges. As an ex- in five dimensions. Thus on the CFT side of the correspondence we ample, the instanton partition function of pure SU(n) super Yang- are dealing with difference or qVOAs. Mills theory is equal to the conformal block of n-Toda CFT which This paper analyzes the relationship between the standard AGT has Wn algebra symmetry, therefore the symmetry algebra is di- approach for SU(n) gauge theory adjoint matter in the presence of rectly related to the number of colors of the gauge group. monodromy defects and the construction of Kimura and Pestun by A different version of the BPS/CFT correspondence can be found embedding both theories into a certain gauge origami construction in papers by Kimura and Pestun [18,19] which can naturally be by Nekrasov [23](see Sec. 2). We then shall consider both con- formulated in five dimensions for quiver gauge theories whose structions at large-n limit and find that the building blocks of qW quivers have shapes of Dynkin diagrams of root system . Accord- algebras and the stable limit of spherical gln double affine Hecke ing to their construction, which will be reviewed in Sec. 3.3, the algebra (DAHA) – the algebra that acts on the Hilbert space of ∗ symmetry of the dual CFT is then given by the W-algebra for the states of codimension two defects of N = 1 theory [15]can be 1 root system . Therefore, in the previous example of pure SU(n) identified up to a simple replacement of equivariant parameters in super Yang-Mills theory, which in quiver language is an A1 quiver the underlying origami picture. Both algebras are realized in terms with color label n, the dual CFT will have Virasoro (W2) symmetry. of oscillators of doubly-deformed Heisenberg algebra (3.2). In other words, the algebra depends on the rank of the quiver. The The approach to the BPS/CFT correspondence via large-n limit is dependence on ranks of individual gauge groups appears in Vira- not new – the mathematical proof of the AGT conjecture for A-type soro constraints at level n which need to be included. In the limit theories without fundamental matter [31]uses it abundantly. Later in [20,21] and then in [15]it was used to study large-n behavior of equivariant K-theory of quiver varieties which had an effective E-mail address: [email protected]. 1 The prescription of extracting W-algebra relations in [18]works beyond the root description in terms of equivariant K-theory of the Hilbert scheme systems. of points on C2. The elliptic Hall algebra, which will appear in https://doi.org/10.1016/j.physletb.2019.135101 0370-2693/© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3. 2 P. Koroteev / Physics Letters B 800 (2020) 135101

∨ where ρa ∈ and the sum is taken over the content of the Young tableau

c A,ω,α = aA,ω,α + a(i − 1) + b( j − 1). (2.3) The above is combined into a single character ⎛ ⎛ ⎞ N = ∗ Fig. 1. Left: 5d 1 (or A0) theory with three-dimensional full monodromy de- fect. Right: 5d A − quiver with U (M) gauge groups. ⎝ ⎝ + ∗ ⎠ n 1 = ¯ +   Tλ P A,ω T A,−ω N A,ω K B,ω+ω A∈6,ω∈∨ ω∈∨ B =A Sec. 3.1, acts on the latter space by means of Nakajima correspon- dences. ∗ − P − K K  , (2.4) Recently gauge origami and vertex operator algebras was stud- 4,ω ω A,ω B,ω ∈ ∨ ied systematically from the point of view of representation theory ω A