COMPARING LQG WITH THE LINEARIZED THEORY

2008 ◽  
Vol 23 (08) ◽  
pp. 1200-1208 ◽  
Author(s):  
ELENA MAGLIARO ◽  
CLAUDIO PERINI

We illustrate the conceptual scenario of the general boundary formulation for field theories and present a brief description of the calculus of graviton propagator in the context of LQG. Then we analyze the possibility of comparing this result with the graviton propagator in perturbative quantum gravity. For this purpose we demonstrate the compatibility of harmonic and radial gauge; it allows to simultaneously impose both gauges and to obtain an expression for the propagator comparable with the one provided by LQG.

Author(s):  
Iosif L. Buchbinder ◽  
Ilya L. Shapiro

This is a short chapter summarizing the main results concerning the renormalization group in models of pure quantum gravity, without matter fields. The chapter starts with a critical analysis of non-perturbative renormalization group approaches, such as the asymptotic safety hypothesis. After that, it presents solid one-loop results based on the minimal subtraction scheme in the one-loop approximation. The polynomial models that are briefly reviewed include the on-shell renormalization group in quantum general relativity, and renormalization group equations in fourth-derivative quantum gravity and superrenormalizable models. Special attention is paid to the gauge-fixing dependence of the renormalization group trajectories.


2011 ◽  
Author(s):  
Daniele Colosi ◽  
Luis Arturo Ureña-López ◽  
Hugo Aurelio Morales-Técotl ◽  
Román Linares-Romero ◽  
Elí Santos-Rodríguez ◽  
...  

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 273
Author(s):  
Mariana Graña ◽  
Alvaro Herráez

The swampland is the set of seemingly consistent low-energy effective field theories that cannot be consistently coupled to quantum gravity. In this review we cover some of the conjectural properties that effective theories should possess in order not to fall in the swampland, and we give an overview of their main applications to particle physics. The latter include predictions on neutrino masses, bounds on the cosmological constant, the electroweak and QCD scales, the photon mass, the Higgs potential and some insights about supersymmetry.


2012 ◽  
Vol 27 (13) ◽  
pp. 1250075 ◽  
Author(s):  
MIR FAIZAL

In this paper, we will study perturbative quantum gravity on supermanifolds with both noncommutativity and non-anticommutativity of spacetime coordinates. We shall first analyze the BRST and the anti-BRST symmetries of this theory. Then we will also analyze the effect of shifting all the fields of this theory in background field method. We will construct a Lagrangian density which apart from being invariant under the extended BRST transformations is also invariant under on-shell extended anti-BRST transformations. This will be done by using the Batalin–Vilkovisky (BV) formalism. Finally, we will show that the sum of the gauge-fixing term and the ghost term for this theory can be elegantly written down in superspace with a two Grassmann parameter.


2011 ◽  
Vol 84 (10) ◽  
Author(s):  
Ratindranath Akhoury ◽  
Ryo Saotome ◽  
George Sterman

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