Publikationer från tidigare år
One-loop tests of supersymmetric gauge theories on spheres
Authors: Joseph A. Minahan and Usman Naseer
Preprint number: UUITP-08/17
We show that a recently conjectured form for perturbative supersymmetric partition functions on spheres of general dimension d is consistent with the flat space limit of 6-dimensional N = 1 super Yang-Mills. We also show that the partition functions for N = 1 8- and 9-dimensional theories are consistent with their known flat space limits.
Explicit Formulae for Yang-Mills-Einstein Amplitudes from the Double Copy
Authors: Marco Chiodaroli, Murat Gunaydin, Henrik Johansson and Radu Roiban
Preprint number: UUITP-07/17
Using the double-copy construction of Yang-Mills-Einstein theories formulated
in our earlier work, we obtain compact presentations for single-trace
Yang-Mills-Einstein tree amplitudes with up to five external gravitons and an
arbitrary number of gluons. These are written as linear combinations of
color-orderd Yang-Mills trees, where the coefficients are given by
color/kinematics-satisfying numerators in a Yang-Mills+\phi^3 theory.
Quantum String Test of Nonconformal Holography
Authors: Xinyi Chen-Lin, Daniel Medina-Rincon and Konstantin Zarembo
Preprint number: UUITP-06/17
We compute Luscher corrections to the effective string tension in the
Pilch-Warner background, holographically dual to N = 2* supersymmetric
Yang-Mills theory. The same quantity can be calculated directly
from field theory by solving the localization matrix model at large-N.
We find complete agreement between the field-theory predictions and
explicit string-theory calculation at strong coupling.
Elliptic Genera of 2d (0,2) Gauge Theories from Brane Brick Models
Authors: Sebastian Franco, Dongwook Ghim, Sangmin Lee, Rak-Kyeong Seong
Preprint Number: UUITP-05/17
We compute the elliptic genus of abelian 2d (0,2) gauge theories corresponding to brane brick models. These theories are worldvolume theories on a single D1-brane probing a toric Calabi-Yau 4-fold singularity. We identify a match with the elliptic genus of the non-linear sigma model on the same Calabi-Yau background, which is computed using a new localization formula. The matching implies that the quantum effects do not drastically alter the correspondence between the geometry and the 2d (0,2) gauge theory. In theories whose matter sector suffers from abelian gauge anomaly, we propose an ansatz for an anomaly cancelling term in the integral formula for the elliptic genus. We provide an example in which two brane brick models related to each other by Gadde-Gukov-Putrov triality give the same elliptic genus.
Integrability in Sigma-Models
Author: K. Zarembo
Preprint Number: UUITP-04/17
Abstract: These lecture notes cover the following topics: (1) Homogeneous spaces, (2) Classical integrability of principal chiral field and semi-symmetric cosets, (3) Topological terms in sigma-models, (4) Backround-field method and beta-function, (5) S-matrix bootstrap in the $O(N)$ model, (6) Supersymmetric cosets.
Connecting Fisher information to bulk entanglement in holography
Authors: Souvik Banerjee, Johanna Erdmenger, Debajyoti Sarkar
Abstract: In the context of relating AdS/CFT to quantum information theory, we propose a holographic dual of Fisher information metric for mixed states in the boundary field theory. This amounts to a holographic measure for the distance between two mixed quantum states. For a spherical subregion in the boundary we show that this is related to a particularly regularized volume enclosed by the Ryu-Takayanagi surface. We further argue that the quantum correction to the proposed Fisher information metric is related to the quantum correction to the boundary entanglement entropy. We discuss consequences of this connection.
Semi-holography illustrated with bi-holography
Authors : Souvik Banerjee, Nava Gaddam, Ayan Mukhopadhyay
Preprint number : UUITP-02/17
Abstract : Semi-holography has been proposed as an effective nonperturbative framework which can combine perturbative and nonperturbative effects consistently for theories like QCD. It is postulated that the strongly coupled nonperturbative sector has a holographic dual in the form of a classical gravity theory in the large N limit, and the perturbative fields determine the gravitational boundary conditions. In this work, we pursue a fundamental derivation of this framework particularly showing how perturbative physics by itself can determine the holographic dual of the infrared, and also the interactions between the perturbative and the holographic sectors. We firstly demonstrate that the interactions between the two sectors can be constrained through the existence of a conserved local energy-momentum tensor for the full system up to hard-soft coupling constants. As an illustration, we set up a bi-holographic toy theory where both the UV and IR sectors are strongly coupled and holographic with distinct classical gravity duals. In this construction, the requirement that an appropriate gluing can cure the singularities (geodetic incompletenesses) of the respective geometries leads us to determine the parameters of the IR theory and the hard-soft couplings in terms of those of the UV theory. The high energy scale behaviour of the hard-soft couplings are state-independent but their runnings turn out to be state-dependent. We discuss how our approach can be adapted to the construction of the semi-holographic framework for QCD.
Gravity Amplitudes as Generalized Double Copies
Authors: Zvi Bern, John Joseph Carrasco, Wei-Ming Chen, Henrik Johansson, Radu Roiban
Preprint Number: UUITP-01/17
Whenever a gauge-theory integrand can be arranged into a form where the BCJ duality between color and kinematics is manifest, a corresponding gravity integrand can be obtained directly via the double copy procedure. However, finding such representations at loop level can be challenging. Here we show that we can instead start from generic gauge-theory integrands, where the duality is not manifest, and apply a modified double-copy procedure that incorporates a set of contact terms generated by violations of dual Jacobi identities. We illustrate this with three-, four- and five-loop examples in N = 8 supergravity.
Elliptic modular double and 4d partition functions
Authors: Rebecca Lodin, Fabrizio Nieri, Maxim Zabzine
Preprint number: UUITP-09/17
We consider 4d supersymmetric (special) unitary quiver gauge theories on compact manifolds which are fibrations over . We show that their partition functions are correlators of vertex operators and screening charges of the modular double version of elliptic algebras. We also consider a generating function of BPS surface defects supported on and show that it can be identified with a particular coherent state in the Fock module over the elliptic Heisenberg algebra.
Quadrality for Supersymmetric Matrix Models
Authors: Sebastian Franco, Sangmin Lee, Rak-Kyeong Seong, Cumrun Vafa
Preprint Number: UUITP-36/16 (arXiv:1612.06859)
We introduce a new duality for N=1 supersymmetric gauged matrix models. This 0d duality is an order 4 symmetry, namely an equivalence between four different theories, hence we call it Quadrality. Our proposal is motivated by mirror symmetry, but is not restricted to theories with a D-brane realization and holds for general N=1 matrix models. We present various checks of the proposal, including the matching of: global symmetries, anomalies, deformations and the chiral ring. We also consider quivers and the corresponding quadrality networks. Finally, we initiate the study of matrix models that arise on the worldvolume of D(-1)-branes probing toric Calabi-Yau 5-folds.
Super-Laplacians and their symmetries
Authors: P.S. Howe and U. Lindström
Preprint number: UUITP-35/16
A super-Laplacian is a set of differential operators in superspace whose highest-dimensional component is given by the spacetime Laplacian. Symmetries of super-Laplacians are given by linear differential operators of arbitrary finite degree and are determined by superconformal Killing tensors. We investigate these operators and their symmetries in flat superspaces. The differential operators form an algebra which can be identified in many cases with the tensor algebra of the relevant superconformal Lie algebra modulo a certain ideal.
Holography, Brane Intersections and Six-dimensional SCFTs
Authors: Nikolay Bobev, Giuseppe Dibitetto, Fridrik Freyr Gautason, Brecht Truijen
Preprint Number: UUITP-34/16
We study supersymmetric intersections of NS5-, D6- and D8-branes in type IIA string theory. We focus on the supergravity description of this system and identify a "near horizon" limit in which we recover the recently classified supersymmetric seven--dimensional AdS solutions of massive type IIA supergravity. Using a consistent truncation to seven-dimensional gauged supergravity we construct a universal supersymmetric deformation of these AdS vacua. In the holographic dual six-dimensional (1,0) superconformal field theory this deformation describes a universal RG flow on the tensor branch of the vacuum moduli space, triggered by a vacuum expectation value for a protected scalar operator of dimension four.
Double Field Theory at SL(2) angles
Authors: Franz Ciceri, Giuseppe Dibitetto, Jose Juan Fernandez-Melgarejo, Adolfo Guarino
Preprint Number: UUITP-33/16
An extended field theory is presented that captures the full SL(2)xO(6,6+n) duality group of four-dimensional half-maximal supergravities. The theory has section constraints whose two inequivalent solutions correspond to minimal D=10 supergravity and chiral half-maximal D=6 supergravity, respectively coupled to vector and tensor multiplets. The relation with O(6,6+n) heterotic double field theory is thoroughly discussed. Non-Abelian interactions as well as background fluxes are captured by a deformation of the generalised diffeomorphisms. Finally, making use of the SL(2) duality structure, it is shown how to generate gaugings with non-trivial de Roo-Wagemans angles via generalised Scherk-Schwarz ansatze. Such gaugings allow for moduli stabilisation including the SL(2) dilaton.
Azurite: An algebraic geometry based package for finding bases of loop integrals
Authors: Alessandro Georgoudis, Kasper J. Larsen and Yang Zhang
Preprint Number: UUITP-32/16
For any given Feynman graph, the set of integrals with all possible powers of the propagators spans a vector space of finite dimension. We introduce the package Azurite (A ZURich-bred method for finding master InTEgrals), which efficiently finds a basis of this vector space. It constructs the needed integration-by-parts (IBP) identities on a set of generalized-unitarity cuts. It is based on syzygy computations and analyses of the symmetries of the involved Feynman diagrams and is powered by the computer algebra systems Singular and Mathematica. It can moreover analytically calculate the part of the IBP identities that is supported on the cuts.
Intersecting surface defects and instanton partition functions
Authors: Yiwen Pan, Wolfger Peelaers
Preprint number: UUITP-31/16
We analyze intersecting surface defects inserted in interacting four-dimensional N = 2 super- symmetric quantum field theories. We employ the realization of a class of such systems as the infrared fixed points of renormalization group flows from larger theories, triggered by perturbed Seiberg-Witten monopole-like configurations, to compute their partition functions. These results are cast into the form of a partition function of 4d/2d/0d coupled systems. Our computations provide concrete expressions for the instanton partition function in the presence of intersecting defects and we study the corresponding ADHM model.
N=2 supersymmetric gauge theory on connected sums of S2×S2
Authors: Guido Festuccia, Jian Qiu, Jacob Winding, Zabzine Maxim
Preprint number: UUITP-30/16
We construct 4D N=2 theories on an infinite family of 4D toric manifolds with the topology of connected sums of S2×S2. These theories are constructed through the dimensional reduction along a non-trivial U(1)-fiber of 5D theories on toric Sasaki-Einstein manifolds. We discuss the conditions under which such reductions can be carried out and give a partial classification result of the resulting 4D manifolds. We calculate the partition functions of these 4D theories and they involve both instanton and anti-instanton contributions, thus generalizing Pestun's famous result on S4.
ADE Spectral Networks and Decoupling Limits of Surface Defects
Authors: Pietro Longhi and Chan Y. Park
Preprint number: UUITP-29/16
We study vacua and BPS spectra of canonical surface defects of class S theories in different decoupling limits using ADE spectral networks. In some regions of the IR moduli spaces of these 2d-4d systems, the mixing between 2d and 4d BPS states is suppressed, and the spectrum of 2d-4d BPS states becomes that of a 2d N=(2,2) theory. For some decoupling limits, we identify the 2d theories describing the surface defects with nonlinear sigma models and coset models that have been previously studied. We also study certain cases where the decoupling limit of a surface defect exhibits a set of vacua and a BPS spectrum that appear to be entirely new. A detailed analysis of these spectra and their wall-crossing behavior is performed.
Wall-Crossing Invariants from Spectral Networks
Authors Pietro Longhi
Preprint Number UUITP-28/16
A new construction of BPS monodromies for 4d N=2 theories of class S is introduced. A novel feature of this construction is its manifest invariance under Kontsevich-Soibelman wall crossing, in the sense that no information on the 4d BPS spectrum is employed. The BPS monodromy is encoded by topological data of a finite graph, embedded into the UV curve C of the theory. The graph arises from a degenerate limit of spectral networks, constructed at maximal intersections of walls of marginal stability in the Coulomb branch of the gauge theory. The topology of the graph, together with a notion of framing, encode equations that determine the monodromy. We develop an algorithmic technique for solving the equations, and compute the monodromy in several examples. The graph manifestly encodes the symmetries of the monodromy, providing some support for conjectural relations to specializations of the superconformal index. For A1-type theories, the graphs encoding the monodromy are "dessins d'enfants" on C, the corresponding Strebel differentials coincide with the quadratic differentials that characterize the Seiberg-Witten curve.
The fate of stringy AdS vacua and the WGC
Authors: Ulf Danielsson and Giuseppe Dibitetto
Preprint number: UUITP-27/16
The authors of arXiv:1610.01533 have recently proposed a stronger version of the weak gravity conjecture (WGC), based on which they concluded that all those non-supersymmetric AdS vacua that can be embedded within a constistent theory of quantum gravity necessarily develop instabilities. In this paper we further elaborate on this proposal by arguing that the aforementioned instabilities have a perturbative nature and arise from the crucial interplay between the closed and the open string sectors of the theory.
Symmetric Wilson Loops beyond leading order
Authors: Xinyi Chen-Lin
Preprint number: UUITP-26/16
We study the circular Wilson loop in the symmetric representation of U(N) in N = 4 super-Yang-Mills (SYM). In the large N limit, we computed the exponentially-suppressed corrections for strong coupling, which suggests non-perturbative physics in the dual holographic theory. We also computed the next-to-leading order term in 1/N, and the result matches with the exact result from the k-fundamental representation.
Intersecting Surface Defects and Two -Dimensional CFT
Authors: Jaume Gomis, Bruno Le Floch, Yiwen Pan, Wolfger Peelaers
Preprint number: UUITP-25/16
We initiate the study of intersecting surface operators/defects in four-dimensional quantum field theories (QFTs). We characterize these defects by coupled 4d/2d/0d theories constructed by coupling the degrees of freedom localized at a point and on intersecting surfaces in spacetime to each other and to the four-dimensional QFT. We construct supersymmetric intersecting surface defects preserving just two supercharges in N = 2 gauge theories. These defects are amenable to exact analysis by localization of the partition function of the underlying 4d/2d/0d QFT. We identify the 4d/2d/0d QFTs describing intersecting surface operators in N = 2 gauge theories realized by intersecting M2-branes ending on N M5-branes wrapping a Riemann surface. We conjecture and provide evidence for an explicit equivalence between the squashed four-sphere partition function of these intersecting defects and correlation functions in Liouville/Toda CFT with the insertion of arbitrary degenerate vertex operators, which are labeled by two highest weights of SU(N).
The thermodynamic Bethe ansatz in a gauge theory
Author: Joseph A. Minahan
Preprint number: UUITP-24/16
In this viewpoint I discuss the paper by Bombardelli, Fioravanti and Tateo.
Multiple elliptic gamma functions associated to cones
Preprint number: UUITP-23/16
We define generalizations of the multiple elliptic gamma functions and the multiple sine functions, associated to good rational cones.
We explain how good cones are related to collections of SL_r(Z) elements and prove that the generalized multiple sine and multiple elliptic gamma functions enjoy infinite product representations and modular properties determined by the cone.
This generalizes the modular properties of the elliptic gamma function studied by Felder and Varchenko, and the results about the usual multiple sine and elliptic gamma functions found by Narukawa.
Introduction to localization in quantum field theory
Authors: Vasily Pestun and Maxim Zabzine
Preprint Number: UUITP-22/16
This is the introductory chapter to the volume. We review the main idea of the localization technique and its brief history both in geometry and in QFT. We discuss localization in diverse dimensions and give an overview of the major applications of the localization calculations for supersymmetric theories. We explain the focus of the present volume.
Background constraints in the infinite tension limit of the heterotic string
Authors: Thales Azevedo and Rennan Lipinski Jusinskas
Preprint Number: UUITP-21/16
In this work we investigate the classical constraints imposed on the supergravity and super Yang-Mills backgrounds in the α′ → 0 limit of the heterotic string using the pure spinor formalism. Guided by the recently observed sectorization of the model, we show that all the ten-dimensional constraints are elegantly obtained from the single condition of nilpotency of the BRST charge.
Torsional Newton-Cartan Geometry from the Noether Procedure
Authors: Guido Festuccia, Dennis Hansen, Jelle Hartong and Niels A. Obers
Preprint Number: UUITP-20/16
We apply the Noether procedure for gauging space-time symmetries to theories with Galilean symmetries, analyzing both massless and massive (Bargmann) realizations. It is shown that at the linearized level the Noether procedure gives rise to (linearized) torsional Newton-Cartan geometry. In the case of Bargmann theories the Newton-Cartan form M couples to the conserved mass current. We show that even in the case of theories with massless Galilean symmetries it is necessary to introduce the form M and that it couples to a topological current. Further, we show that the Noether procedure naturally gives rise to a distinguished affine (Christoffel type) connection that is linear in M and torsionful. As an application of these techniques we study the coupling of Galilean electrodynamics to TNC geometry at the linearized level.
Symmetries and Couplings of Non-Relativistic Electrodynamics
Authors: Guido Festuccia, Dennis Hansen, Jelle Hartong and Niels A. Obers
Preprint Number: UUITP-19/16
We examine three versions of non-relativistic electrodynamics, known as the electric and magnetic limit theories of Maxwell's equations and Galilean electrodynamics (GED) which is the off-shell non-relativistic limit of Maxwell plus a free scalar field. For each of these three cases we study the couplings to non-relativistic dynamical charged matter (point particles and charged complex scalars). The GED theory contains besides the electric and magnetic potentials a so-called mass potential making the mass parameter a local function. The electric and magnetic limit theories can be coupled to twistless torsional Newton-Cartan geometry while GED can be coupled to an arbitrary torsional Newton-Cartan background. The global symmetries of the electric and magnetic limit theories on flat space consist in any dimension of the infinite dimensional Galilean conformal algebra and a U(1) current algebra. For the on-shell GED theory this symmetry is reduced but still infinite dimensional, while off-shell only the Galilei algebra plus two dilatations remain. Hence one can scale time and space independently, allowing Lifshitz scale symmetries for any value of the critical exponent z.
Hodge Numbers for All CICY Quotients
Authors: Andrei Constantin, James Gray and Andre Lukas
Preprint Number: UUITP-18/16
We present a general method for computing Hodge numbers for Calabi-Yau manifolds realised as discrete quotients of complete intersections in products of projective spaces. The method relies on the computation of equivariant cohomologies and is illustrated for several explicit examples. In this way, we compute the Hodge numbers for all discrete quotients obtained in Braun's classification arXiv:1003.3235.
Matrix models for 5d super Yang-Mills
Authors: Joseph A. Minahan
Preprint Number: UUITP-17/16
In this contribution to the review on localization in gauge theories we investigate the matrix models derived from localizing N=1 super Yang-Mills on S^5. We consider the large-N limit and attempt to solve the matrix model by a saddle-point approximation. In general it is not possible to find an analytic solution, but at the weak and the strong limits of the 't Hooft coupling there are dramatic simplifications that allows us to extract most of the interesting information. At weak coupling we show that the matrix model is close to the Gaussian matrix model and that the free-energy scales as N^2. At strong coupling we show that if the theory contains one adjoint hypermultiplet then the free-energy scales as N^3. We also find the expectation value of a supersymmetric Wilson loop that wraps the equator. We demonstrate how to extract the effective couplings and reproduce results of Seiberg. Finally, we compare to results for the six-dimensional (2,0) theory derived using the AdS/CFT correspondence. We show that by choosing the hypermultiplet mass such that the supersymmetry is enhanced to N=2, the Wilson loop result matches the analogous calculation using AdS/CFT. The free-energies differ by a rational fraction.
Superintegrability of Geodesic Motion on the Sausage Model
Authors: Gleb Arutyunov, Martin Heinze and Daniel Medina-Rincon
Preprint number: UUITP-16/16
Reduction of the η-deformed sigma model on AdS5×S5 to the two-dimensional squashed sphere (S2)η can be viewed as a special case of the Fateev sausage model where the coupling constant ν is imaginary. We show that geodesic motion in this model is described by a certain superintegrable mechanical system with four-dimensional phase space. This is done by means of explicitly constructing three integrals of motion which satisfy the sl(2) Poisson algebra relations, albeit being non-polynomial in momenta. Further, we find a canonical transformation which transforms the Hamiltonian of this mechanical system to the one describing the geodesic motion on the usual two-sphere. By inverting this transformation we map geodesics on this auxiliary two-sphere back to the sausage model. This paper is a tribute to the memory of Prof. Petr Kulish.
Infinitesimal moduli of G2 holonomy manifolds with instanton bundles
Authors: X. de la Ossa, M. Larfors, and E. Svanes
Preprint number: UUITP-15/16
We describe the infinitesimal moduli space of pairs (Y,V) where Y is a manifold with G2 holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical G2 cohomology developed by Reyes-Carrion and Fernandez and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli H^1(Y,End(V)) plus the moduli of the G2 structure preserving the instanton condition. The latter piece is contained in H^1(Y,TY), and is given by the kernel of a map which generalises the concept of the Atiyah map for holomorphic bundles on complex manifolds to the case at hand. In fact, the map is given in terms of the curvature of the bundle and maps H^1(Y,TY) into H^2(Y,End(V)), and moreover can be used to define a cohomology on an extension bundle of TY by End(V). We comment further on the resemblance with the holomorphic Atiyah algebroid and connect the story to physics, in particular to heterotic compactifications on (Y,V) when α′=0.
All (4,1): Sigma Models with (4,p) Off-Shell Supersymmetry
Författare: Chris Hull and Ulf Lindström,
Off-shell (4, p) supermultiplets in 2-dimensions are constructed for p = 0, 1, 2, 4. These are used to construct sigma models whose target spaces are hyperka ̈hler with torsion. The off- shell supersymmetry implies the three complex structures are simultaneously integrable and allows us to construct actions using extended extended superspace and projective superspace, giving an explicit construction of the target space geometries.
Integrability of the \eta-deformed Neumann-Rosochatius model
Authors: Gleb Arutyunov, Martin Heinze, Daniel Medina-Rincon
Preprint Number: UUITP-13/16
An integrable deformation of the well-known Neumann-Rosochatius system is studied by considering generalised bosonic spinning solutions on the \eta-deformed AdS_5 x S^5 background. For this integrable model we construct a 4x4 Lax representation and a set of integrals of motion that ensures its Liouville integrability. These integrals of motion correspond to the deformed analogues of the Neumann-Rosochatius integrals and generalise the previously found integrals for the \eta-deformed Neumann and AdS_5 x S^5_\eta geodesic systems. Finally, we briefly comment on consistent truncations of this model.
Yukawa Unification in Heterotic String TheoryAuthors: Evgeny I. Buchbinder, Andrei Constantin, James Gray, Andre LukasPreprint Number: UUITP-12/16
We analyze Yukawa unification in the the context of E8×E8 heterotic Calabi-Yau models which rely on breaking to a GUT theory via a non-flat gauge bundle and subsequent Wilson line breaking to the standard model. Our focus is on underlying GUT theories with gauge group SU(5) or SO(10). We provide a detailed analysis of the fact that, in contrast to traditional field theory GUTs, the underlying GUT symmetry of these models does not enforce Yukawa unification. Using this formalism, we present various scenarios where Yukawa unification can occur as a consequence of additional symmetries. These additional symmetries arise naturally in some heterotic constructions and we present an explicit heterotic line bundle model which realizes one of these scenarios.
Universal isolation in the AdS landscapeAuthors: Ulf H. Danielsson, Giuseppe Dibitetto and Sergio C. VargasPreprint Number: UUITP-11/16
We study the universal conditions for quantum non-perturbative stability against bubble nucleation for pertubatively stable AdS vacua based on positive energy theorems. We also compare our analysis with the pre-existing ones in the literature carried out within the thin-wall approximation. The aforementioned criterion is then tested in two explicit examples describing massive type IIA string theory compactified on S3 and S3 x S3, respectively. The AdS landscape of both classes of compactifications is known to consist of a set of isolated points.
The main result is that all critical points respecting the Breitenlohner-Freedaman (BF) bound also turn out be stable at a non-perturbative level. Finally, we speculate on the possible universal features that may be extracted from the above specific examples.
q-Virasoro modular double and 3d partition functionsAuthors: Anton Nedelin, Fabrizio Nieri and Maxim ZabzinePreprint Number: UUITP-10/16
We study partition functions of 3d N = 2 U(N) gauge theories on compact manifolds which are S1 fibrations over S2. We show that the partition functions are free field correlators of vertex operators and screening charges of the q-Virasoro modular double, which we define. The inclusion of supersymmetric Wilson loops in arbitrary representations allows us to show that the generating functions of Wilson loop vacuum expectation values satisfy two SL(2,Z)-related commuting sets of q-Virasoro constraints. We generalize our construction to special types of 3d N = 2 unitary quiver gauge theories and as an example we give the free boson realization of the ABJ(M) model.
Review of localization for 5D supersymmetric gauge theoriesAuthors: Jian Qiu and Maxim ZabzinePreprint Number: UUITP-09/16
We give a pedagogical review of the localization of supersymmetric gauge theory on 5D toric Sasaki-Einstein manifolds. We construct the cohomological complex resulting from supersymmetry and consider its natural toric deformations with all equivariant parameters turned on. We also give detailed discussion on how the Sasaki-Einstein geometry permeates every aspect of the calculation, from Killing spinor, vanishing theorems to the index theorems.
Localization and AdS/CFT CorrespondenceAuthors: K. ZaremboPreprint Number: UUITP-08/16
An interplay between localization and holography is reviewed with the emphasis on the AdS_5/CFT_4 correspondence.
Exploring the BTZ bulk with boundary conformal blocksAuthors: Bruno Carneiro da Cunha and Monica GuicaPreprint Number: UUITP-07/16
We point out a simple relation between the bulk field at an arbitrary radial position and the boundary OPE, by placing some old work by Ferrara, Gatto, Grillo and Parisi in the AdS/CFT context. This gives us, in principle, a prescription for extracting the classical bulk field from the boundary conformal block, and also clarifies why the latter is computed by a geodesic Witten diagram. We apply this prescription to the BTZ black hole - viewed as a pure state created by the insertion of a heavy operator in the boundary CFT_2 - and use it to relate a classical field in the bulk to a heavy-light Virasoro conformal block in the boundary. In particular, we obtain a relation between the radial bulk position and the conformal ratios in the boundary CFT. We use this to show that the singular points of the radial bulk equation occur when the dual boundary operators approach each other and that the associated bulk monodromies map to monodromies of the (appropriately transformed) conformal block, thus providing a CFT interpretation of the radial monodromy.
Calabi-Yau Threefolds With Small Hodge NumbersAuthors: Philip Candelas, Andrei Constantin and Challenger MishraPreprint Number: UUITP-06/16
We present a master list of Calabi-Yau threefolds, known to us, with small Hodge numbers, which we understand to be those manifolds with height (h1,1+h2,1)≤24. With the completion of a project to compute the Hodge numbers of all free quotients of complete intersection Calabi-Yau threefolds by Candelas et. al., many new points have been added to the tip of the Hodge plot, updating the reviews by Davies and Candelas. In view of this and other recent constructions of Calabi-Yau threefolds with small height we have produced an updated list.
A new 6d fixed point from holography
Authors: Fabio Apruzzi, Giuseppe Dibitetto and Luigi Tizzano
Preprint Number: UUITP-05/16
We propose a stringy construction giving rise to a class of interacting and non-supersymmetric CFT's in six dimensions. Such theories may be obtained as an IR conformal fixed point of an RG flow ending up in a (1, 0) theory in the UV. We provide the due holographic evidence in the context of massive type IIA on AdS7 x M3, where M3 is topologically an S3. In particular, in this paper we present a 10d flow solution which may be interpreted as a non-BPS bound state of NS5, D6 and anti-D6 branes. Moreover, by adopting its 7d effective desciption, we are able to holographically compute the free energy and the operator spectrum in the novel IR conformal fixed point.
The Vector-like Twin HiggsAuthors: Nathaniel Craig, Simon Knapen, Pietro Longhi, Matthew StrasslerPreprint Number: UUITP-04/16
We present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.
ADE Spectral NetworksAuthors: Pietro Longhi and Chan Y. ParkPreprint number: UUITP-03/16
We introduce a new perspective and a generalization of spectral networks for 4d N=2 theories of class S associated to Lie algebras g = A_n, D_n, E_6, and E_7. Spectral networks directly compute the BPS spectra of 2d theories on surface defects coupled to the 4d theories. A Lie algebraic interpretation of these spectra emerges naturally from our construction, leading to a new description of 2d-4d wall-crossing phenomena. Our construction also provides an efficient framework for the study of BPS spectra of the 4d theories. In addition, we consider novel types of surface defects associated with minuscule representations of g.
Level Crossing in Random Matrices: I. Random perturbation of a fixed matrixAuthors: B. Shapiro and K. ZaremboPreprint number: UUITP-02/16
The force awakens - the 750 GeV diphoton excess at the LHC from a varying electromagnetic couplingAuthors: Ulf Danielsson, Rikard Enberg, Gunnar Ingelman and Tanumoy MandalPreprint number: UUITP-01/16
We show that the recent 750 GeV diphoton excess observed at the LHC may be explained by the production of a scalar of the type involved in Bekenstein's framework for varying-alpha theories, with the difference that the scalar in our model has a large mass. The model has only two free parameters, the mass of the scalar and the scale of this new physics, which are fixed by the LHC excess to 750 GeV and 3-4 TeV, respectively. We discuss collider and cosmology aspects of the model, and give predictions for future LHC searches. In particular, the scalar is dominantly produced by quark-antiquark fusion in association with a photon or a fermion pair. In addition, it can be produced in the s-channel in photon-photon fusion. Its dominating decay is to diphotons, but it also has a large three-body decay to a fermion pair and a photon, which provides an interesting search channel with a dilepton-photon resonance at 750 GeV. We also comment on the possibility that the new physics is related to extra dimensions or string theory.