Publikationer 2019
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The Full-Color Two-Loop Four-Gluon Amplitude in N = 2 Super-QCD
Authors: Claude Duhr, Henrik Johansson, Gregor Kälin, Gustav Mogull, and Bram Verbeek
Preprint number: UUITP-14/19
Abstract: We present the fully integrated form of the two-loop four-gluon amplitude in N=2 supersymmetric quantum chromodynamics with gauge group SU(Nc) and with Nf massless supersymmetric quarks (hypermultiplets) in the fundamental representation. Our result maintains full dependence on Nc and Nf , and relies on the existence of a compact integrand representation that exhibits the duality between color and kinematics. Specializing to the N=2 superconformal theory, where Nf = 2Nc , we obtain remarkably simple amplitudes that have an analytic structure close to that of N=4 super-Yang-Mills theory, except that now certain lower-weight terms appear. We comment on the corresponding results for other gauge groups.
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AdS3 vacua and surface defects in massive IIA
Authors: Giuseppe Dibitetto and Nicolò Petri
Preprint Number: UUITP-13/19
Abstract: We summarize the results and the ideas in [1–3] where new warped AdS3 backgrounds are derived in massive IIA string theory by uplifting exact solutions in N=1,d=7 and N= (1,1), d=6 gauged supergravities. These solutions are respectively asymptotically AdS7 and AdS6 and theyare related to the D2-D4-NS5-D6-D8 brane intersection. We provide a particular supergravity solution in 10d describing this bound state and we discuss the relations between its near-horizongeometry and the uplifts from 6d and 7d. Then we give the holographic interpretations of these AdS3 warped backgrounds in terms of N= (0,4) defect SCFT2 within the N= (1,0) SCFT6 and the N=2 SCFT5.
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Superpotential of Three Dimensional N=1 Heterotic Supergravity
Authors: Xenia de la Ossa, Magdalena Larfors, Matthew Magill, Eirik E. Svanes
Preprint Number: UUITP-12/19
Abstract: We dimensionally reduce the ten dimensional heterotic action on spacetimes of the form M(2,1)×Y, where M(2,1) is three dimensional maximally symmetric Anti de Sitter or Minkowski space, and Y is a compact seven dimensional manifold with G2 structure. In doing so, we derive the real superpotential functional of the corresponding three dimensional N=1 theory. We confirm that extrema of this functional precisely correspond to supersymmetric heterotic compactifications on manifolds of G2 structure. We make some comments on the role of the superpotential functional with respect to the coupled moduli problem of instanton bundles over G2 manifolds.
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Strong Kähler with Torsion as Generalised Geometry
Authors: Chris Hull and Ulf Lindström
Preprint number: UUITP-11/19
Abstract: Strong Kähler with Torsion is the target space geometry of (2,1) and (2,0) supersymmetric nonlinear sigma models. We discuss how it can be represented in terms of Generalised Complex Geometry in analogy to the Gualtieri map from the geometry of (2,2) supersymmetric nonlinear sigma modelsto Generalised Kähler Geometry.
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Quenched coupling, entangled equilibria, and correlated composite operators: a tale of two O(N) models
Authors : Souvik Banerjee, Julius Engelsoy, Jorge Larana-Aragon, Bo Sundborg, Larus Thorlacius, Nico Wintergerst.
Preprint number : UUITP-10/19
A macroscopic version of Einstein-Podolsky-Rosen entanglement is obtained by quenching a linear coupling between two O(N) vector models. A quench of the mixed vacuum produces an excited entangled state, reminiscent of puried thermal equilibrium, whose properties can be studied analytically in the free limit of the individual field theories. The decoupling of different wavelength modes in free field theory prevents true thermalisation but a more subtle difference is that the density operator obtained by a partial trace does not commute with the post-quench Hamiltonian. Approximately thermal behaviour is obtained in the limit of weak initial mixing and a smooth but rapid quench. More surprisingly, late time correlation functions of composite operators in the post-quench free field theory share interesting properties with correlators in strongly coupled systems.
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Chiral Estimate of QCD Pseudocritical Line
Author: K. Zarembo
Preprint number: UUITP-9/19
Relatively low crossover temperature suggests that chiral symmetry restoration in QCD may well be described within the low-energy effective theory. The shape of the pseudocritical line in the T-mu plane is estimated within this assumption. No critical endpoint is found for physical values of quark masses.
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A Bound on Thermal Relativistic Correlators at Large Spacelike Momenta
Authors: Souvik Banerjee, Kyriakos Papadodimas, Suvrat Raju, Prashant Samantray, Pushkal Shrivastava
Preprint number: UUITP-7/19
We consider thermal Wightman correlators in a relativistic quantum field theory in the limit where the spatial momenta of the insertions become large while their frequencies stay fixed. We show that, in this limit, the size of this correlator is bounded by exp(-βR) where R is the radius of the smallest sphere that contains the polygon formed by the momenta. We argue that, generically, perturbative quantum field theories can saturate this bound through suitably high-order loop diagrams. We also consider holographic theories in d-spacetime dimensions where we show that the leading two-point function of generalized free-fields in such theories saturates the bound in d = 2 and is below the bound for d > 2. We briefly discuss interactions in holographic theories and conclude with a discussion of several open problems.
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Constructing stable de Sitter in M-theory from higher curvature corrections
Authors: Johan Blåbäck, Ulf Danielsson, Giuseppe Dibitetto, Suvendu Giri
Preprint number: UUITP-6/19
We consider dimensional reductions of M-theory on T⁷/ℤ₂³ with the inclusion of arbitrary metric flux and spacetime filling KK monopoles. With these ingredients at hand, we are able to construct a novel family of non-supersymmetric yet tachyon free Minkowski extrema. These solutions are supported by pure geometry with no extra need for gauge fluxes and possess a fully stable perturbative mass spectrum, up to a single flat direction. Such a direction corresponds to the overall internal volume, with respect to which the scalar potential exhibts a no-scale behavior. We then provide a mechanism that lifts the flat direction to give it a positive squared mass while turning Mkw₄ into dS₄ The construction makes use of the combined effect of G₇ flux and higher curvature corrections. Our solution is scale separated and the qunatum corrections are small. Finally we speculate on novel possibilities when it comes to scale hierarchies within a given construction of this type, and possible issues with the choice of quantum vacuum.
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The fate of the Konishi multiplet in the β-deformed Quantum Spectral Curve
Authors: Christian Marboe, Erik Widen
Preprint number: UUITP-5/19
We investigate the solution space of the β-deformed Quantum Spectral Curve by studying a sample of solutions corresponding to single-trace operators that in the undeformed theory belong to the Konishi multiplet. We discuss how to set the precise boundary conditions for the leading Q-system for a given state, how to solve it, and how to build perturbative corrections to the Pμ-system. We confirm and add several loop orders to known results in the literature.
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Boundary gauge and gravitational anomalies from Ward identities
Author: Vladimir Prochazka
Preprint number: UUITP-4/19
Abstract: We consider the two-point functions of conserved bulk currents and energy-momentum tensor in a boundary CFT defined on $\mathbb{R}_-^{1,2}$. Starting from the consistent forms of boundary gauge and gravitational anomalies we derive their respective contributions to the correlation functions in the form of anomalous Ward identities. Using the recently developed momentum space formalism we find an anomalous solution to each of these identities depending on a single undetermined form-factor. We study the solution in two different kinematic limits corresponding to small and large momentum $p_n$, perpendicular to the boundary. We find that the anomalous term interpolates between a non-local form resembling the standard anomaly-induced term in a two-dimensional CFT at small $p_n$ and Chern-Simons contact terms at large $p_n$. Using this we derive some consistency conditions regarding the dependence of these anomalies on the boundary conditions and discuss possible cancellation mechanisms. These ideas are then demonstrated on the explicit example of free, massless three-dimensional fermion. In particular we manage to obtain the respective anomalies via a diagrammatic momentum space computation and expose the well-known relation between bulk parity anomaly and boundary gauge anomalies.
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Cardy-like asymptotics of the 4d N=4 index and AdS_5 blackholes
Author: Arash Arabi Ardehali
Preprint number: UUITP-3/19
Choi, Kim, Kim, and Nahmgoong have recently pioneered analyzing a Cardy-like limit of the superconformal index of the 4d N=4 theory with complexified fugacities which encodes the entropy of the dual supersymmetric AdS_5 blackholes. Here we study the Cardy-like asymptotics of the index within the rigorous framework of elliptic hypergeometric integrals, thereby filling a gap in their derivation of the blackhole entropy function, finding a new blackhole saddle-point, and demonstrating novel bifurcation phenomena in the asymptotics of the index as a function of fugacity phases. We also comment on the relevance of the supersymmetric Casimir energy to the blackhole entropy function in the present context.
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Branes, partition functions and quadratic monopole superpotentials
Authors: Antonio Amariti, Luca Cassia, Ivan Garozzo, Noppadol Mekareeya
Preprint number: UUITP-2/19
We obtain the brane setup describing 3d N=2 dualities for USp(2Nc) and U(Nc) SQCD with monopole superpotentials. This classification follows from a complete analysis of affine and twisted affine compactifications from 4d. The analysis leads to a new duality for the unitary case that has been previously overlooked in the literature. We check this by matching of the three sphere partition function of the two sides of this new duality and find a perfect agreement. Furthermore we use the partition function to predict new 3d N=2 dualities for SQCD with monopole superpotentials and tensorial matter.
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N = 2* Phase Transitions and Holography
Authors: Jorge G. Russo, Erik Widen, Konstantin Zarembo
Preprint number: UUITP-1/19
We clarify the relationship between probe analysis of the supergravity dual and the large-N solution of the localization matrix model for the planar N = 2* super-Yang-Mills theory. A formalism inspired by supergravity allows us to systematically solve the matrix model at strong coupling. Quite surprisingly, we find that quantum phase transitions, known to occur in the N = 2* theory, start to be visible at the third order of the strong-coupling expansion and thus constitute a perturbative phenomenon on the string worldsheet.