Publikationer från tidigare år
PUBLIKATIONER 2017

BPS Graphs: From Spectral Networks to BPS Quivers
Authors: Maxime Gabella, Pietro Longhi, Chan Y. Park and Masahito Yamazaki
Preprint number: UUITP11/17
We define “BPS graphs” on punctured Riemann surfaces associated with A_{N−1} theories of class S. BPS graphs provide a bridge between two powerful frameworks for studying the spectrum of BPS states: spectral networks and BPS quivers. They arise from degenerate spectral networks at maximal intersections of walls of marginal stability on the Coulomb branch. While the BPS spectrum is illdefined at such intersections, a BPS graph captures a useful basis of elementary BPS states. The topology of a BPS graph encodes a BPS quiver, even for higherrank theories and for theories with certain partial punctures. BPS graphs lead to a geometric realization of the combinatorics of FockGoncharov Ntriangulations and generalize them in several ways.

Elliptic modular double and 4d partition functions
Authors: Rebecca Lodin, Fabrizio Nieri, Maxim Zabzine
Preprint number: UUITP09/17
We consider 4d supersymmetric (special) unitary G quiver gauge theories on compact manifolds which are T2 fibrations over S2. We show that their partition functions are correlators of vertex operators and screening charges of the modular double version of elliptic W(G) algebras. We also consider a generating function of BPS surface defects supported on T2 and show that it can be identified with a particular coherent state in the Fock module over the elliptic Heisenberg algebra.

Oneloop tests of supersymmetric gauge theories on spheres
Authors: Joseph A. Minahan and Usman Naseer
Preprint number: UUITP08/17
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 6dimensional N = 1 super YangMills. We also show that the partition functions for N = 1 8 and 9dimensional theories are consistent with their known flat space limits.

Explicit Formulae for YangMillsEinstein Amplitudes from the Double Copy
Authors: Marco Chiodaroli, Murat Gunaydin, Henrik Johansson and Radu Roiban
Preprint number: UUITP07/17
Using the doublecopy construction of YangMillsEinstein theories formulated
in our earlier work, we obtain compact presentations for singletrace
YangMillsEinstein tree amplitudes with up to five external gravitons and an
arbitrary number of gluons. These are written as linear combinations of
colororderd YangMills trees, where the coefficients are given by
color/kinematicssatisfying numerators in a YangMills+\phi^3 theory. 
Quantum String Test of Nonconformal Holography
Authors: Xinyi ChenLin, Daniel MedinaRincon and Konstantin Zarembo
Preprint number: UUITP06/17
We compute Luscher corrections to the effective string tension in the
PilchWarner background, holographically dual to N = 2* supersymmetric
YangMills theory. The same quantity can be calculated directly
from field theory by solving the localization matrix model at largeN.
We find complete agreement between the fieldtheory predictions and
explicit stringtheory calculation at strong coupling. 
Elliptic Genera of 2d (0,2) Gauge Theories from Brane Brick Models
Authors: Sebastian Franco, Dongwook Ghim, Sangmin Lee, RakKyeong Seong
Preprint Number: UUITP05/17
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 D1brane probing a toric CalabiYau 4fold singularity. We identify a match with the elliptic genus of the nonlinear sigma model on the same CalabiYau 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 GaddeGukovPutrov triality give the same elliptic genus.

Integrability in SigmaModels
Author: K. Zarembo
Preprint Number: UUITP04/17
Abstract: These lecture notes cover the following topics: (1) Homogeneous spaces, (2) Classical integrability of principal chiral field and semisymmetric cosets, (3) Topological terms in sigmamodels, (4) Backroundfield method and betafunction, (5) Smatrix bootstrap in the $O(N)$ model, (6) Supersymmetric cosets.

Connecting Fisher information to bulk entanglement in holography
Authors: Souvik Banerjee, Johanna Erdmenger, Debajyoti Sarkar
Preprint: UUITP03/17
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 RyuTakayanagi 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.

Semiholography illustrated with biholography
Authors : Souvik Banerjee, Nava Gaddam, Ayan Mukhopadhyay
Preprint number : UUITP02/17
Abstract : Semiholography 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 energymomentum tensor for the full system up to hardsoft coupling constants. As an illustration, we set up a biholographic 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 hardsoft couplings in terms of those of the UV theory. The high energy scale behaviour of the hardsoft couplings are stateindependent but their runnings turn out to be statedependent. We discuss how our approach can be adapted to the construction of the semiholographic framework for QCD.

Gravity Amplitudes as Generalized Double Copies
Authors: Zvi Bern, John Joseph Carrasco, WeiMing Chen, Henrik Johansson, Radu Roiban
Preprint Number: UUITP01/17
Whenever a gaugetheory 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 gaugetheory integrands, where the duality is not manifest, and apply a modified doublecopy procedure that incorporates a set of contact terms generated by violations of dual Jacobi identities. We illustrate this with three, four and fiveloop examples in N = 8 supergravity.
Publikationer 2016

Elliptic modular double and 4d partition functions
Authors: Rebecca Lodin, Fabrizio Nieri, Maxim Zabzine
Preprint number: UUITP09/17
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, RakKyeong Seong, Cumrun Vafa
Preprint Number: UUITP36/16 (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 Dbrane 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 CalabiYau 5folds.

SuperLaplacians and their symmetries
Authors: P.S. Howe and U. Lindström
Preprint number: UUITP35/16
A superLaplacian is a set of differential operators in superspace whose highestdimensional component is given by the spacetime Laplacian. Symmetries of superLaplacians 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 Sixdimensional SCFTs
Authors: Nikolay Bobev, Giuseppe Dibitetto, Fridrik Freyr Gautason, Brecht Truijen
Preprint Number: UUITP34/16
We study supersymmetric intersections of NS5, D6 and D8branes 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 sevendimensional AdS solutions of massive type IIA supergravity. Using a consistent truncation to sevendimensional gauged supergravity we construct a universal supersymmetric deformation of these AdS vacua. In the holographic dual sixdimensional (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 FernandezMelgarejo, Adolfo Guarino
Preprint Number: UUITP33/16
An extended field theory is presented that captures the full SL(2)xO(6,6+n) duality group of fourdimensional halfmaximal supergravities. The theory has section constraints whose two inequivalent solutions correspond to minimal D=10 supergravity and chiral halfmaximal D=6 supergravity, respectively coupled to vector and tensor multiplets. The relation with O(6,6+n) heterotic double field theory is thoroughly discussed. NonAbelian 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 nontrivial de RooWagemans angles via generalised ScherkSchwarz 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: UUITP32/16
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 ZURichbred method for finding master InTEgrals), which efficiently finds a basis of this vector space. It constructs the needed integrationbyparts (IBP) identities on a set of generalizedunitarity 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: UUITP31/16
We analyze intersecting surface defects inserted in interacting fourdimensional 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 SeibergWitten monopolelike 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: UUITP30/16
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 nontrivial U(1)fiber of 5D theories on toric SasakiEinstein 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 antiinstanton 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: UUITP29/16
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 2d4d systems, the mixing between 2d and 4d BPS states is suppressed, and the spectrum of 2d4d 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 wallcrossing behavior is performed.

WallCrossing Invariants from Spectral Networks
Authors Pietro Longhi
Preprint Number UUITP28/16
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 KontsevichSoibelman 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 A1type theories, the graphs encoding the monodromy are "dessins d'enfants" on C, the corresponding Strebel differentials coincide with the quadratic differentials that characterize the SeibergWitten curve.

The fate of stringy AdS vacua and the WGC
Authors: Ulf Danielsson and Giuseppe Dibitetto
Preprint number: UUITP27/16
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 nonsupersymmetric 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 ChenLin
Preprint number: UUITP26/16
We study the circular Wilson loop in the symmetric representation of U(N) in N = 4 superYangMills (SYM). In the large N limit, we computed the exponentiallysuppressed corrections for strong coupling, which suggests nonperturbative physics in the dual holographic theory. We also computed the nexttoleading order term in 1/N, and the result matches with the exact result from the kfundamental representation.

Intersecting Surface Defects and Two Dimensional CFT
Authors: Jaume Gomis, Bruno Le Floch, Yiwen Pan, Wolfger Peelaers
Preprint number: UUITP25/16
Abstract:
We initiate the study of intersecting surface operators/defects in fourdimensional 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 fourdimensional 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 M2branes ending on N M5branes wrapping a Riemann surface. We conjecture and provide evidence for an explicit equivalence between the squashed foursphere 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: UUITP24/16
In this viewpoint I discuss the paper by Bombardelli, Fioravanti and Tateo.

Multiple elliptic gamma functions associated to cones
Author:Jacob Winding
Preprint number: UUITP23/16
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: UUITP22/16
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: UUITP21/16
In this work we investigate the classical constraints imposed on the supergravity and super YangMills 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 tendimensional constraints are elegantly obtained from the single condition of nilpotency of the BRST charge.

Torsional NewtonCartan Geometry from the Noether Procedure
Authors: Guido Festuccia, Dennis Hansen, Jelle Hartong and Niels A. Obers
Preprint Number: UUITP20/16
We apply the Noether procedure for gauging spacetime 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 NewtonCartan geometry. In the case of Bargmann theories the NewtonCartan 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 NonRelativistic Electrodynamics
Authors: Guido Festuccia, Dennis Hansen, Jelle Hartong and Niels A. Obers
Preprint Number: UUITP19/16
We examine three versions of nonrelativistic electrodynamics, known as the electric and magnetic limit theories of Maxwell's equations and Galilean electrodynamics (GED) which is the offshell nonrelativistic limit of Maxwell plus a free scalar field. For each of these three cases we study the couplings to nonrelativistic dynamical charged matter (point particles and charged complex scalars). The GED theory contains besides the electric and magnetic potentials a socalled mass potential making the mass parameter a local function. The electric and magnetic limit theories can be coupled to twistless torsional NewtonCartan geometry while GED can be coupled to an arbitrary torsional NewtonCartan 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 onshell GED theory this symmetry is reduced but still infinite dimensional, while offshell 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: UUITP18/16
We present a general method for computing Hodge numbers for CalabiYau 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 YangMills
Authors: Joseph A. Minahan
Preprint Number: UUITP17/16
In this contribution to the review on localization in gauge theories we investigate the matrix models derived from localizing N=1 super YangMills on S^5. We consider the largeN limit and attempt to solve the matrix model by a saddlepoint 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 freeenergy scales as N^2. At strong coupling we show that if the theory contains one adjoint hypermultiplet then the freeenergy 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 sixdimensional (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 freeenergies differ by a rational fraction.

Superintegrability of Geodesic Motion on the Sausage Model
Authors: Gleb Arutyunov, Martin Heinze and Daniel MedinaRincon
Preprint number: UUITP16/16
Reduction of the ηdeformed sigma model on AdS5×S5 to the twodimensional 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 fourdimensional phase space. This is done by means of explicitly constructing three integrals of motion which satisfy the sl(2) Poisson algebra relations, albeit being nonpolynomial 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 twosphere. By inverting this transformation we map geodesics on this auxiliary twosphere 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: UUITP15/16
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 noncompact seven dimensional spaces, e.g. domain walls. Employing the canonical G2 cohomology developed by ReyesCarrion 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) OffShell Supersymmetry
Författare: Chris Hull and Ulf Lindström,
Preprintnummer: UUITP14/16
Offshell (4, p) supermultiplets in 2dimensions 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 \etadeformed NeumannRosochatius model
Authors: Gleb Arutyunov, Martin Heinze, Daniel MedinaRincon
Preprint Number: UUITP13/16
An integrable deformation of the wellknown NeumannRosochatius system is studied by considering generalised bosonic spinning solutions on the \etadeformed 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 NeumannRosochatius integrals and generalise the previously found integrals for the \etadeformed 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 Theory
Authors: Evgeny I. Buchbinder, Andrei Constantin, James Gray, Andre LukasPreprint Number: UUITP12/16We analyze Yukawa unification in the the context of E8×E8 heterotic CalabiYau models which rely on breaking to a GUT theory via a nonflat 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 landscape
Authors: Ulf H. Danielsson, Giuseppe Dibitetto and Sergio C. VargasPreprint Number: UUITP11/16We study the universal conditions for quantum nonperturbative stability against bubble nucleation for pertubatively stable AdS vacua based on positive energy theorems. We also compare our analysis with the preexisting ones in the literature carried out within the thinwall 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 BreitenlohnerFreedaman (BF) bound also turn out be stable at a nonperturbative level. Finally, we speculate on the possible universal features that may be extracted from the above specific examples. 
qVirasoro modular double and 3d partition functions
Authors: Anton Nedelin, Fabrizio Nieri and Maxim ZabzinePreprint Number: UUITP10/16We 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 qVirasoro 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 qVirasoro 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 theories
Authors: Jian Qiu and Maxim ZabzinePreprint Number: UUITP09/16We give a pedagogical review of the localization of supersymmetric gauge theory on 5D toric SasakiEinstein 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 SasakiEinstein geometry permeates every aspect of the calculation, from Killing spinor, vanishing theorems to the index theorems.

Localization and AdS/CFT Correspondence
Authors: K. ZaremboPreprint Number: UUITP08/16An interplay between localization and holography is reviewed with the emphasis on the AdS_5/CFT_4 correspondence.

Exploring the BTZ bulk with boundary conformal blocks
Authors: Bruno Carneiro da Cunha and Monica GuicaPreprint Number: UUITP07/16We 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 heavylight 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.

CalabiYau Threefolds With Small Hodge Numbers
Authors: Philip Candelas, Andrei Constantin and Challenger MishraPreprint Number: UUITP06/16We present a master list of CalabiYau threefolds, known to us, with small Hodge numbers, which we understand to be those manifolds with height (h^{1,1}+h^{2,1})≤24. With the completion of a project to compute the Hodge numbers of all free quotients of complete intersection CalabiYau 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 CalabiYau 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: UUITP05/16
We propose a stringy construction giving rise to a class of interacting and nonsupersymmetric 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 nonBPS bound state of NS5, D6 and antiD6 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 Vectorlike Twin Higgs
Authors: Nathaniel Craig, Simon Knapen, Pietro Longhi, Matthew StrasslerPreprint Number: UUITP04/16We present a version of the twin Higgs mechanism with vectorlike 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 fourdimensional UV completion and discuss a variety of UV completions relevant for both vectorlike and fraternal twin Higgs models.

ADE Spectral Networks
Authors: Pietro Longhi and Chan Y. ParkPreprint number: UUITP03/16We 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 2d4d wallcrossing 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 matrix
Authors: B. Shapiro and K. ZaremboPreprint number: UUITP02/16 
The force awakens  the 750 GeV diphoton excess at the LHC from a varying electromagnetic coupling
Authors: Ulf Danielsson, Rikard Enberg, Gunnar Ingelman and Tanumoy MandalPreprint number: UUITP01/16We 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 varyingalpha 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 34 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 quarkantiquark fusion in association with a photon or a fermion pair. In addition, it can be produced in the schannel in photonphoton fusion. Its dominating decay is to diphotons, but it also has a large threebody decay to a fermion pair and a photon, which provides an interesting search channel with a dileptonphoton resonance at 750 GeV. We also comment on the possibility that the new physics is related to extra dimensions or string theory.