Existence of black holes due to concentration of angular momentum

We present a general sufficient condition for the formation of black holes due to concentration of angular momentum. This is expressed in the form of a universal inequality, relating the size and angular momentum of bodies, and is proven in the context of axisymmetric initial data sets for the Einstein equations which satisfy an appropriate energy condition. A brief comparison is also made with more traditional black hole existence criteria based on concentration of mass

Spectral functions in V-QCD with matter: masses, susceptibilities, diffusion and conductivity

We consider a holographic model of QCD in the Veneziano limit of a large number of colors N c and flavors N f but fixed x = N f /N c (V-QCD). The model exhibits a first order deconfined but chirally broken transition, followed by a second order chirally restored transition in the μ − T plane for a range of plausible holographic parameters. We study the quasi-normal mode spectrum, and derive the pertinent vector and axial spectral functions across the transition regions. The pole masses, susceptibilities, diffusion constants and electric conductivity are also discussed. In particular, the pole masses are found to survive the deconfining transition, to quickly dissolve in the the chirally restored phase by developing substantial widths. The flavor electric conductivities arise sharply in the transition region. The flavor susceptibility is shown to be consistent with the one derived from bulk thermodynamics

Weyl anomaly induced stress tensors in general manifolds

Considering arbitrary conformal field theories in general (non-conformally flat) backgrounds, we adopt a dimensional regularization approach to obtain stress tensors from Weyl anomalies. The results of Type A anomaly-induced stress tensors in four and six dimensions generalize the previous results calculated in a conformally flat background. On the other hand, regulators are needed to have well-defined Type B anomaly-induced stress tensors. We also discuss ambiguities related to Type D anomalies, Weyl invariants and order of limit issues

Testing electroweak baryogenesis with future colliders

Electroweak Baryogenesis (EWBG) is a compelling scenario for explaining the matter-antimatter asymmetry in the universe. Its connection to the electroweak phase transition makes it inherently testable. However, completely excluding this scenario can seem difficult in practice, due to the sheer number of proposed models. We investigate the possibility of postulating a “no-lose” theorem for testing EWBG in future e + e − or hadron colliders. As a first step we focus on a factorized picture of EWBG which separates the sources of a stronger phase transition from those that provide new sources of CP violation. We then construct a “nightmare scenario” that generates a strong first-order phase transition as required by EWBG, but is very difficult to test experimentally. We show that a 100 TeV hadron collider is both necessary and possibly sufficient for testing the parameter space of the nightmare scenario that is consistent with EWBG

Localization of supersymmetric Chern-Simons-Matter theory on a squashed S 3 with SU(2) × U(1) isometry

Localization of supersymmetric N $$\mathcal{N}$$ = 2 Chern-Simons-Matter theory on a squashed S 3 with SU(2) × U(1) isometry has been studied by different groups of authors. In this paper, we localize the theory on a squashed S 3 with SU(2) × U(1) isometry and a class of complex background. We see that certain kinds of shifts of the background gauge fields are crucial in obtaining nontrivial results, and the previously found results on this manifold can be incorporated in our results as special limits

5d Higgs branch localization, Seiberg-Witten equations and contact geometry

In this paper we apply the idea of Higgs branch localization to 5d supersymmetric theories of vector multiplet and hypermultiplets, obtained as the rigid limit of N $$\mathcal{N}$$ = 1 supergravity with all auxiliary fields. On supersymmetric K-contact/Sasakian background, the Higgs branch BPS equations can be interpreted as 5d generalizations of the Seiberg-Witten equations. We discuss the properties and local behavior of the solutions near closed Reeb orbits. For U(1) gauge theories, which can be straight-forwardly generalized to theories whose gauge group can be completely broken, we show the suppression of the deformed Coulomb branch, and the partition function is dominated by 5d Seiberg-Witten solutions. For squashed S 5 and Y pq manifolds, we show the matching between poles in the perturbative Coulomb branch matrix model, and the bound on local winding numbers of the BPS solutions

Testing general relativity on accelerators

Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable – maximal energy of the scattered photons – would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC

Thermal corrections to Rényi entropies for conformal field theories

We compute thermal corrections to Rényi entropies of d dimensional conformal field theories on spheres. Consider the n th Rényi entropy for a cap of opening angle 2 θ on S d −1 . From a Boltzmann sum decomposition and the operator-state correspondence, the leading correction is related to a certain two-point correlation function of the operator (not equal to the identity) with smallest scaling dimension. More specifically, via a conformal map, the correction can be expressed in terms of the two-point function on a certain conical space with opening angle 2 πn . In the case of free conformal field theories, this two-point function can be computed explicitly using the method of images. We perform the computation for the conformally coupled scalar. From the n → 1 limit of our results, we extract the leading thermal correction to the entanglement entropy, reproducing results of arXiv:1407.1358

Calabi–Yau metrics and string compactification

Yau proved an existence theorem for Ricci-flat Kähler metrics in the 1970s, but we still have no closed form expressions for them. Nevertheless there are several ways to get approximate expressions, both numerical and analytical. We survey some of this work and explain how it can be used to obtain physical predictions from superstring theory

Marginal deformations of N=4 SYM and open vs. closed string parameters

We make precise the connection between the generic Leigh–Strassler deformation of N=4 SYM and noncommutativity. We construct an appropriate noncommutativity matrix, which turns out to define a nonassociative deformation. Viewing this noncommutativity matrix as part of the set of open string data which characterize the deformation and mapping them to the closed string data (e.g. metric and B-field), we are able to construct the gravity dual and the corresponding deformed flat space geometry up to third order in the deformation parameter ρ