Fri - 05/13/22

Group field theory on 2-groups

  • Authors: Florian Girelli, Matteo Laudonio, Adrian Tanasa, Panagiotis Tsimiklis
  • Subjects: High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2205.05837
  • Abstract Group field theories are quantum field theories built on groups. They can be seen as a tool to generate topological state-sums or quantum gravity models. For four dimensional manifolds, different arguments have pointed towards 2-groups (such as crossed modules) as the relevant symmetry structure to probe four dimensional topological features. Here, we introduce a group field theory built on crossed modules which generate a four dimensional topological model, as we prove that the Feynman diagram amplitudes can be related by Pachner moves. This model is presumably the dual version of the Yetter-Mackaay model.

There is no new related paper today

  1. [2205.05935] - Singularities of regular black holes and the art of monodromy method for asymptotic quasinormal modes - Chen Lan, Yi-Fan Wang

  2. [2205.05693] - Towards Explicit Discrete Holography: Aperiodic Spin Chains from Hyperbolic Tilings - Pablo Basteiro, Giuseppe Di Giulio, Johanna Erdmenger, Jonathan Karl, René Meyer, Zhuo-Yu Xian

  3. [2205.05705] - Computing spacetime - Juan F. Pedraza, Andrea Russo, Andrew Svesko, Zachary Weller-Davies

Thu - 05/12/22

On 3-Dimensional Quantum Gravity and Quasi-Local Holography in Spin Foam Models and Group Field Theory

  • Authors: Gabriel Schmid
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2205.05079
  • Abstract This thesis is devoted to the study of 3-dimensional quantum gravity as a spin foam model and group field theory. In the first part of this thesis, we review some general physical and mathematical aspects of 3-dimensional gravity, focusing on its topological nature. Afterwards, we review some important aspects of the Ponzano-Regge spin foam model for 3-dimensional Riemannian quantum gravity and explain in some details how it is related to the discretized path integral of general relativity in its first-order formulation. Furthermore, we discuss briefly some related spin foam models and review the notion of spin network states in order to properly define transition amplitudes of these models. The main results of this thesis are contained in the second part. We start by reviewing the Boulatov group field theory and explain how it is related to the Ponzano-Regge model and some advantages of introducing colouring. Afterwards, we give a very detailed review of the topology of coloured graphs with non-empty boundary and review techniques, which are devolved in crystallization theory, a branch of geometric topology. In the last part of this chapter, we apply these techniques in order to define suitable boundary observables and transition amplitudes of this model and in order to set up a formalism for dealing with transition amplitudes in the coloured Boulatov model in a more systematic way by writing them as topological expansions. We also apply these techniques to the simplest possible boundary state representing a 2-sphere. Last but not least, we review some results regarding quasi-local holography in the Ponzano-Regge model, construct some explicit examples of coloured graphs representing manifolds with torus boundary and discuss the transition amplitude of some fixed boundary graph representing a 2-torus.

On 3-Dimensional Quantum Gravity and Quasi-Local Holography in Spin Foam Models and Group Field Theory

  • Authors: Gabriel Schmid
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2205.05079
  • Abstract This thesis is devoted to the study of 3-dimensional quantum gravity as a spin foam model and group field theory. In the first part of this thesis, we review some general physical and mathematical aspects of 3-dimensional gravity, focusing on its topological nature. Afterwards, we review some important aspects of the Ponzano-Regge spin foam model for 3-dimensional Riemannian quantum gravity and explain in some details how it is related to the discretized path integral of general relativity in its first-order formulation. Furthermore, we discuss briefly some related spin foam models and review the notion of spin network states in order to properly define transition amplitudes of these models. The main results of this thesis are contained in the second part. We start by reviewing the Boulatov group field theory and explain how it is related to the Ponzano-Regge model and some advantages of introducing colouring. Afterwards, we give a very detailed review of the topology of coloured graphs with non-empty boundary and review techniques, which are devolved in crystallization theory, a branch of geometric topology. In the last part of this chapter, we apply these techniques in order to define suitable boundary observables and transition amplitudes of this model and in order to set up a formalism for dealing with transition amplitudes in the coloured Boulatov model in a more systematic way by writing them as topological expansions. We also apply these techniques to the simplest possible boundary state representing a 2-sphere. Last but not least, we review some results regarding quasi-local holography in the Ponzano-Regge model, construct some explicit examples of coloured graphs representing manifolds with torus boundary and discuss the transition amplitude of some fixed boundary graph representing a 2-torus.
  1. [2205.05356] - Spontaneous Symmetry Breaking without classical fields: a Functional Renormalization Group approach - A. Jakovac, P. Mati, P. Posfay

Wed - 05/11/22

There is no new related paper today

There is no new related paper today

  1. [2205.05064] - Holography of the Photon Ring - Shahar Hadar, Daniel Kapec, Alexandru Lupsasca, Andrew Strominger

  2. [2205.04532] - Large Field Distances from EFT strings - Stefano Lanza, Fernando Marchesano, Luca Martucci, Irene Valenzuela

Tue - 05/10/22

Probing the interior of the Schwarzschild black hole using congruences: LQG vs GUP

  • Authors: Saeed Rastgoo, Saurya Das
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2205.03799
  • Abstract We review, as well as provide some new results regarding the study of the structure of spacetime and the singularity in the interior of the Schwarzschild black hole in both loop quantum gravity and generalized uncertainty principle approaches, using congruences and their associated expansion scalar and the Raychaudhuri equation. We reaffirm previous results that in loop quantum gravity, in all three major schemes of polymer quantization, the expansion scalar, Raychaudhuri equation and the Kretschmann scalar remain finite everywhere in the interior. In the context of the generalized uncertainty principle, we show that only two of the four models we study lead to similar results. These two models have the property that their algebra is modified by configuration variables rather than the momenta.

Aspects of self-dual Yang-Mills and self-dual gravity

  • Authors: Pratik Chattopadhyay
  • Subjects: High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2205.03675
  • Abstract In this thesis, we study the all same helicity loop amplitudes in self-dual Yang-Mills and self-dual gravity. These amplitudes have long been conjectured to be interpreted as an anomaly and are recently linked to the UV divergence of two-loop quantum gravity. In the first part of the thesis, we study the loop amplitudes in self-dual Yang-Mills. We show that the four point one-loop amplitude can be reduced to a computation of shifts, which strongly suggests a case for an anomaly interpretation. We next propose a new formula for the one-loop amplitudes at all multiplicity, in terms of the Berends-Giele currents connected by an effective propagator. We prove the formula by observing that it readily implies the correct collinear properties. To demonstrate the validity of our formula, we do an explicit computation at 3, 4 and 5 points and reproduce the known results. The region momenta variables play an important role in our formula and thus it points to both the worldsheet and the momentum twistor interpretations. In the second part of the thesis, we study the one loop behaviour of chiral Einstein-Cartan gravity and the one-loop amplitudes in self-dual gravity.

There is no new related paper today

  1. [2205.03412] - Generalized symmetries and Noether’s theorem in QFT - Valentin Benedetti, Horacio Casini, Javier M. Magan

Mon - 05/09/22

There is no new related paper today

There is no new related paper today

  1. [2205.03216] - Testing non-local gravity by clusters of galaxies - Filippo Bouchè, Salvatore Capozziello, Vincenzo Salzano, Keiichi Umetsu

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