Conference

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Gravitational RG flows on foliated spacetimes

Frank Saueressig Radboud Universiteit Nijmegen

April 24, 2014

PIRSA:14040106
One-loop renormalization in a toy model of Horava-Lifshitz gravity

Dario Benedetti Ecole Polytechnique - CPHT

April 24, 2014

PIRSA:14040105
Phases of Gravity

Petr Horava University of California, Berkeley

April 24, 2014

PIRSA:14040104
On background-independent renormalization in state-sum model

Benjamin Bahr Universität Hamburg

April 24, 2014

PIRSA:14040101
Global flows in quantum gravity

Jan Pawlowski Universität Heidelberg - Institut für Theoretische Physik

April 24, 2014

PIRSA:14040100
Grassmann tensor network renormalization and fermionic topological quantum field theory: a new route towards quantum gravity

Zheng-Cheng Gu Chinese University of Hong Kong

April 24, 2014

PIRSA:14040099
Refinement limit of quantum group spinnets

Mercedes Martin-Benito Complutense University of Madrid

April 23, 2014

PIRSA:14040098
Asymptotic safety in a pure matrix model

Jan Ambjorn University of Copenhagen

April 23, 2014

PIRSA:14040097
Asymptotic safety in a pure matrix model

Tim Koslowski Technical University of Applied Sciences Würzburg-Schweinfurt

April 23, 2014

PIRSA:14040096
What happens to the Schwarzschild solution in quantum corrected gravity?

Kellogg Stelle Imperial College London

April 23, 2014

PIRSA:14040094
Confronting Asymptotically Safe Inflation with Planck data

Alfio Bonanno National Institute for Astrophysics (INAF)

April 23, 2014

PIRSA:14040093
Lessons from asymptotic safety

Daniel Litim University of Sussex

April 23, 2014

PIRSA:14040092

Gravitational RG flows on foliated spacetimes

Frank Saueressig Radboud Universiteit Nijmegen

April 24, 2014

PIRSA:14040106

The role of time and a possible foliation structure of spacetime are longstanding questions which lately received a lot of renewed attention from the quantum gravity community. In this talk, I will review recent progress in formulating a Wetterich-type functional renormalization group equation on foliated spacetimes and outline its potential applications. In particular, I will discuss first results concerning the RG flow of
Horava-Lifshitz gravity, highlighting a possible mechanism for a dynamical Lorentz-symmetry restoration at low energies.
One-loop renormalization in a toy model of Horava-Lifshitz gravity

Dario Benedetti Ecole Polytechnique - CPHT

April 24, 2014

PIRSA:14040105

I will present some recent results on the UV properties of a toy model of Horava-Lifshitz gravity in 2+1 dimensions. In particular, I will illustrate some details of a one-loopcalculation, leading to beta functions for the running couplings. The renormalization group flow obtained in such way shows that Newton's constant is asymptotically free. However, the DeWitt
supermetric approaches its Weyl invariant form with the same speed and the effective interaction coupling of the scalar degree of freedom remains constant along the flow. I will discuss some general lesson that we can learn from these results.
Phases of Gravity

Petr Horava University of California, Berkeley

April 24, 2014

PIRSA:14040104

Quantum gravity with anisotropic scaling exhibits a rich structure of phases and phase transitions, dominated by multicritical behavior dependent on the spacetime dimension and the dynamical critical exponent. I will discuss some features of this phase structure, as well as its similarities and differences in comparison to the CDT approach to quantum gravity.
On background-independent renormalization in state-sum model

Benjamin Bahr Universität Hamburg

April 24, 2014

PIRSA:14040101

In this talk we discuss some notion of coarse graining in state-sums, most notably a class of spin foam models in their holonomy representations. We discuss the notion of scale in this context, and how diffeomorphism-invariance ties into the existence of a continuum limit. We close with an example and muse about the interplay between diffeomorphism-invariance and non-renormalizability.
Global flows in quantum gravity

Jan Pawlowski Universität Heidelberg - Institut für Theoretische Physik

April 24, 2014

PIRSA:14040100

In this talk I present recent work on complete UV-IR flows for the fully momentum-dependent propagator, RG-consistent vertices, Newtons coupling and the cosmological constant. For the first time, a global phase diagram is obtained where the non-Gaussian ultraviolet fixed point of asymptotic safety is connected via smooth trajectories to an infrared fixed point with classical scaling. Physics implications as well as the extension to gauge-matter-gravity systems are discussed.
Grassmann tensor network renormalization and fermionic topological quantum field theory: a new route towards quantum gravity

Zheng-Cheng Gu Chinese University of Hong Kong

April 24, 2014

PIRSA:14040099

Recently, the development of tensor network renormalization approach has provided us a powerful tool to construct new classes of topological quantum field theories(TQFTs) in discrete space-time. For example, the Turaev Viro’s states sum constructions are fixed point tensor networks representing a special class of 2+1D TQFTs. Interestingly, the Grassmann variable generalization of tensor network renormalization approach leads to new classes of TQFTs for interacting fermion systems, namely, the fermionic TQFTs. In this talk, I will start with a fermionic topological nonlinear sigma model and discuss its corresponding new mathematics - group super-cohomology theory. Then I will explain the fermionic generalization of Dijkgraaf -Witten gauge theory by using group supercohomology theory. Finally I will show examples beyond fermionic Dijkgraaf -Witten gauge theory and discuss possible new routes towards quantum gravity.
Refinement limit of quantum group spinnets

Mercedes Martin-Benito Complutense University of Madrid

April 23, 2014

PIRSA:14040098

The many-building-blocks limit of spin foam models remains to be an open question. The complexity of these models makes the analysis of their possible continuum phases a very difficult task. In the last years progress in this direction has been made by considering simplified, yet featured-rich, analog models to spin foams, the so-called spin net models. These models retain the main dynamical ingredient of spin foams, namely the simplicity constraints. In this talk we will introduce spin net models based on the quantum group SU(2)_q, and we will review the use of tensor network renormalization group techniques to study their coarse graining. We will analyze the resulting phase diagram, which interestingly displays a rich structure of fixed points. Furthermore we will discuss the relation of spin nets with spin foams.
Asymptotic safety in a pure matrix model

Jan Ambjorn University of Copenhagen

April 23, 2014

PIRSA:14040097

An attempt is made to define "lines of contant physics" in CDT and relate the corresponding picture to non-trivial UV fixed points as they appear in the asymptotic safety scenario.
Asymptotic safety in a pure matrix model

Tim Koslowski Technical University of Applied Sciences Würzburg-Schweinfurt

April 23, 2014

PIRSA:14040096

The connection between two-dimensional Euclidean gravity and pure matrix models has lead to may fundamental insights about quantum gravity and string theory. The pure matrix model is thus a blueprint for the connection between discrete models and Euclidean quantum gravity. I will report on work with Astrid Eichhorn in which this "blueprint" model is investigated with the functional renormalization group. In this model, I will discuss the questions: "What is a possible meaning of asymptotic safety in a discrete model?" and "Is it possible to apply the FRGE to tensor models?
What happens to the Schwarzschild solution in quantum corrected gravity?

Kellogg Stelle Imperial College London

April 23, 2014

PIRSA:14040094
Confronting Asymptotically Safe Inflation with Planck data

Alfio Bonanno National Institute for Astrophysics (INAF)

April 23, 2014

PIRSA:14040093
Lessons from asymptotic safety

Daniel Litim University of Sussex

April 23, 2014

PIRSA:14040092

Two aspects of asymptotic safety are highlighted. First, I discuss how asymptotic safety can be tested with the help of a bootstrap strategy. This is then applied to high-order polynomial actions of the Ricci scalar and beyond. Second, I discuss how phenomenological signatures of asymptotic safety can be searched for at particle colliders such as the LHC, provided that the quantum gravity scale is in the TeV energy regime.

Title	Speaker(s)	Date	Talk Type	Info link
Gravitational RG flows on foliated spacetimes	Frank Saueressig	2014-04-24	Conference	View details
One-loop renormalization in a toy model of Horava-Lifshitz gravity	Dario Benedetti	2014-04-24	Conference	View details
Phases of Gravity	Petr Horava	2014-04-24	Conference	View details
On background-independent renormalization in state-sum model	Benjamin Bahr	2014-04-24	Conference	View details
Global flows in quantum gravity	Jan Pawlowski	2014-04-24	Conference	View details
Grassmann tensor network renormalization and fermionic topological quantum field theory: a new route towards quantum gravity	Zheng-Cheng Gu	2014-04-24	Conference	View details
Refinement limit of quantum group spinnets	Mercedes Martin-Benito	2014-04-23	Conference	View details
Asymptotic safety in a pure matrix model	Jan Ambjorn	2014-04-23	Conference	View details
Asymptotic safety in a pure matrix model	Tim Koslowski	2014-04-23	Conference	View details
What happens to the Schwarzschild solution in quantum corrected gravity?	Kellogg Stelle	2014-04-23	Conference	View details
Confronting Asymptotically Safe Inflation with Planck data	Alfio Bonanno	2014-04-23	Conference	View details
Lessons from asymptotic safety	Daniel Litim	2014-04-23	Conference	View details

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