Dual Infrared Limits of 6D N=(2,0) Theory
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Physics Letters B 793 (2019) 297–302 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Dual infrared limits of 6d N = (2, 0) theory ∗ Olaf Lechtenfeld a,b, , Alexander D. Popov a a Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany b Riemann Center for Geometry and Physics, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany a r t i c l e i n f o a b s t r a c t 4 2 3 ˜ 1 Article history: Compactifying type AN−1 6d N =(2, 0) supersymmetric CFT on a product manifold M × = M × S × 1 1 ˜ 1 4 Received 19 November 2018 S × I either over S or over S leads to maximally supersymmetric 5d gauge theories on M × I or 3 2 1 ˜ 1 Accepted 25 February 2019 on M × , respectively. Choosing the radii of S and S inversely proportional to each other, these Available online 3 May 2019 5d gauge theories are dual to one another since their coupling constants e2 and e˜2 are proportional to Editor: M. Cveticˇ those radii respectively. We consider their non-Abelian but non-supersymmetric extensions, i.e. SU(N) 4 × I 3 × 2 4 ⊃ 3 = × 2 Yang–Mills theories on M and on M , where M M Rt T p with time t and a punctured 2 2-torus, and I ⊂ is an interval. In the first case, shrinking I to a point reduces to Yang–Mills theory 4 or to the Skyrme model on M , depending on the method chosen for the low-energy reduction. In the 3 second case, scaling down the metric on M and employing the adiabatic method, we derive in the 2 infrared limit a non-linear SU(N) sigma model with a baby-Skyrme-type term on , which can be reduced further to AN−1 Toda theory. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license 3 (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP . 1. Introduction and summary them. However, we are not aware of a geometric derivation of the AGT correspondence. The famous Alday-Gaiotto-Tachikawa (AGT) 2d-4d correspon- Recently, a derivation of the AGT correspondence via reduction 4 2 dence [1] relates Liouville field theory on a punctured Rie- of 6d CFT to M and was discussed in [6–9]. A relation between 2 mann surface and SU(2) super-Yang–Mills (SYM) theory on AN−1 6d CFT compactified on a circle and 5d SU(N) SYM was 4 a four-dimensional manifold M (see e.g. [2]for a nice review employed as well as further reduction to complex Chern-Simons 2 4 and references). This correspondence was quickly extended to theory on × I, where I ⊂ M is an interval. Then a generalized 2d AN−1 Toda field theory and 4d SU(N) SYM [3]. Since then version of the correspondence between 3d Chern-Simons theory various AGT-like correspondences between theories on n-and and 2d CFT was used, with the Nahm-pole boundary conditions (6 − n)-dimensional manifolds were investigated (see e.g. [4,5]) translating to the constraints reducing WZW models to Toda theo- for reviews and references). One way to interpret these correspon- ries [7–9]. N = dences is to start from 6d (2, 0) supersymmetric conformal In this paper we consider SU(N) Yang–Mills theories on man- − n × 6 n n 4 3 2 4 3 ˜ 1 field theory (CFT) on M M . The theory on M would appear ifolds M × I and M × , where M = M × S is Lorentzian − 6 n 2 ∼ 1 as a low-energy limit when M shrinks to a point, while the the- and = S × I is a two-sphere with two punctures. The two − 6 n n 3 ˜ 1 ory on M would emerge when M is scaled down to a point [2, manifolds agree in M × I but differ in the additional circle S = 1 4,5]. To be more precise, the AGT correspondence for n 4 relates versus S . The supersymmetric extensions of Abelian gauge the- 4 2 the partition function of 6d CFT of type A − on M × with N 1 ories on these two 5d manifolds originate from type AN−1 6d partition functions of theories on M4 and 2, which are all equal 4 2 1 N = (2, 0) supersymmetric CFT on M × , compactified on S or due to the conformal invariance of the 6d theory. The standard ˜ 1 ˜ S with radii R1 = εR0 or R1 = ε˜ R0, respectively [10–12]. Choos- way of establishing such correspondences consists of calculating −1 ing ε˜ = ε the two 5d theories become dual to each other, and n 6−n partition/correlation functions on M and M and to compare 2 2 their gauge coupling constants e or e˜ (in units of the reference scale R0) will be inversely proportional to one another, which is consistent with the arguments from [13]. In order to have non- * Corresponding author. 3 2 trivial vacuum solutions we take M = Rt × T with a temporal E-mail addresses: [email protected] (O. Lechtenfeld), p 2 [email protected] (A.D. Popov). direction Rt and a one-punctured 2-torus T p . https://doi.org/10.1016/j.physletb.2019.02.051 0370-2693/© 2019 The Authors. 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. 298 O. Lechtenfeld, A.D. Popov / Physics Letters B 793 (2019) 297–302 ˜ 4 For further low-energy limits we introduce two scales, R and R, Gauge fields on M × I. The gauge potential A (connection) and which determine the sizes of the two factors in the product man- the gauge field F (curvature) both take values in the Lie algebra 4 3 2 4 ifolds M × IR and M × , respectively. In the first case, via × I R˜ R˜ R su(N). On M ˜ R we have ˜ R (R, R) = (R0, εR0) and ε 1we shrink IR to a point. Depend- A = A aˆ + A ing on the choice of reduction – translational invariance along IR aˆ dx z dz and N ≥ (2.7) or adiabatic approach [14–18,4]– one obtains ( 2 extended) F = 1 F aˆ ∧ bˆ + F aˆ ∧ 4 2 aˆbˆ dx dx azˆ dx dz . Yang–Mills theory or the Skyrme model on the manifold M . In R0 ˜ For the generators I in the fundamental N × N representation the second case, taking (R, R) = (ε˜ R0, R0) and ε˜ 1we scale i 1 2 of SU(N) we use the normalization tr(Ii I j) =− δij for i, j = down the metric on Rt and T p . The adiabatic method [15–22]then 2 2 i i produces a non-linear sigma model with a baby-Skyrme-type term 1, ..., N − 1 and write A = A Ii and F = F Ii . 2 aˆbˆ aˆbˆ zz −2 on . Finally, we briefly discuss a reduction of this 2d SU(N) For the metric tensor (2.6)we have g = η and g = R . It R0 R R 2 sigma model to Toda field theory on . follows that R0 To summarize, we propose a geometric background for estab- ˆ ˆ ˆ ˆ ˆ − ˆ 4 Fab = Fab Faz = 2Faz lishing 4d-2d AGT correspondences between field theories on M R and R R . (2.8) and 2. We argue that these correspondences depend not only on The standard Yang–Mills action functional with this metric takes the topology of M4 and 2 but also on the method employed for the form deriving the low-energy effective field theories in the infrared (us- R ing symmetries, adiabatic limit, constraints etc.). =− 4 F Faˆbˆ + 2 F Fazˆ S5 d x dz tr aˆbˆ 2 azˆ , (2.9) 8e2 R 4 2. Two dual ways from 6d to 5d Yang–Mills theory M ×I 2 where e is the gauge coupling constant. It is known [13] that e 6d manifold. We consider the purported 6d Abelian N = (2, 0) 1 is proportional to the S compactification radius R1=εR0. A full CFT on the manifold supersymmetric extension of (2.9)can be found e.g. in [4]. 4 × 2 = 3 × ˜ 1 × 1 × I 3 = × 2 M M ˜ S ˜ S R R , where M ˜ Rt T p 3 2 R R1 1 R Reduction to M × . Alternatively, let us put R1 = R and shrink (2.1) S˜ 1 by taking ˜ is a temporal cylinder over a two-torus with size R and a punc- ˜ R1 = ε˜ R0 R0 with ε˜ 1 . (2.10) ˜ 1 1 ture p. The radii of the circles S and S and the length of the interval I are indicated. The metric on this space is taken as This reduction produces the 5d super-Maxwell theory on 2 a b 3 2 4 2 5 2 3 2 2 1 ds = η dx dx + (dx ) + (dx ) + (dx ) M ˜ × = Rt × T × S × IR (2.11) 6 ab R R p R ˜ 2 2 2 2 = R −(dt) + (dα) + (dβ) (2.2) with a metric ˜ 2 2 2 2 2 2 ¯ + R (dϕ) + R (dθ) + R (dz) , 2 ˜ 2 2 2 2 a¯ b 1 1 ds˜ = R −(dt) + (dα) + (dβ) + δ¯ ¯ dx dx R˜ ab (2.12) = ¯ where a, b 0, 1, 2, and all spatial coordinates in the second line with a¯, b ∈{4, 5} . range over [−π, π], with the Greek ones being periodic.