Bouncing evolution in a model of loop quantum gravity

Cong, Zixiang; Lewandowski, Jerzy; Li, Haida; Ma, Yongge

doi:10.1103/physrevd.99.124012

Cited by 27 publications

(17 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are also some other recent results based on the simplicity of this Hamiltonian (see e.g. [47,76,77]. However as is mentioned in Section 6.3, the semiclassical limit of the scalar curvature operator has not yet been checked in the literature for the most general situation.…”

Section: Singularity Resolution and Bouncementioning

confidence: 97%

Effective dynamics from coherent state path integral of full loop quantum gravity

Han

Liu

2020

Phys. Rev. D

View full text Add to dashboard Cite

A new routine is proposed to relate Loop Quant Cosmology (LQC) to Loop Quantum Gravity (LQG) from the perspective of effective dynamics. We derive the big-bang singularity resolution and big bounce from the first principle of full canonical LQG. Our results are obtained in the framework of the reduced phase space quantization of LQG. As a key step in our work, we derive with coherent states a new discrete path integral formula of the transition amplitude generated by the physical Hamiltonian. The semiclassical approximation of the path integral formula gives an interesting set of effective equations of motion (EOMs) for full LQG. When solving the EOMs with homogeneous and isotropic ansatz, we reproduce the LQC effective dynamics in µ 0 -scheme. The solution replaces the big-bang singularity by a big bounce. In the end, we comment on the possible relation between theμ-scheme of effective dynamics and the continuum limit of the path integral formula. arXiv:1910.03763v2 [gr-qc] 23 Dec 20191 The result is also valid in the case of an infinite space. 2 E(γ) and V(γ) denote the set of edges and vertices in γ.

show abstract

Section: Singularity Resolution and Bouncementioning

confidence: 97%

Effective dynamics from coherent state path integral of full loop quantum gravity

Han

Liu

2020

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…In contrast to the other singularity theorems, the conditions required by the Hawking-Penrose singularity theorem are the easiest to implement physically and cover a wide a e-mail: minyongguo@pku.edu.cn b e-mail: lipch2019@pku.edu.cn (corresponding author) range of areas. Up to now, many attempts have been made to eliminate the singularity, which includes and is not limited to considering quantum corrections [3][4][5] and alternative gravities [6]. Recently, a novel 4D Einstein-Gauss-Bonnet (EGB) gravity was formulated by D. Glavan and Lin [7].…”

Section: Introductionmentioning

confidence: 99%

Innermost stable circular orbit and shadow of the 4D Einstein–Gauss–Bonnet black hole

Guo

2020

Eur. Phys. J. C

215

View full text Add to dashboard Cite

Recently, a novel 4D Einstein-Gauss-Bonnet gravity was formulated by Glavan and Lin (Phys Rev Lett 124(8):081301, 2020). Although whether the theory is well defined is currently debatable, the spherically symmetric black hole solution is still meaningful and worthy of study. In this paper, we study the geodesic motions in the spacetime of the spherically symmetric black hole solution. First of all, we find that a negative GB coupling constant is allowable, as in which case the singular behavior of the black hole can be hidden inside the event horizon. Then we calculate the innermost stable circular orbits for massive particles, which turn out to be monotonic decreasing functions of the GB coupling constant. Furthermore, we study the unstable photon sphere and shadow of the black hole. It is interesting to find that the proposed universal bounds on black hole size in Lu and Lyu (Phys Rev D 101(4):044059, 2020) recently can be broken when the GB coupling constant takes a negative value.

show abstract

“…where in the third line we used (5) and in the last line we used equation (9). It could be argued that the choice w = p would lead to the correct result.…”

Section: A Multi-sector Strategymentioning

confidence: 99%

“…Since LQC is an independent theory never derived from Loop Quantum Gravity (LQG) [6,7], the question whether the full theory would lead to similar dynamical predictions is highly nontrivial. The direct computation of the genuine quantum dynamics in LQG is outside of technical reach (except in some unphysical toy examples [8,9]). Observation of the success of effective dynamics in LQC led to the expectation that a similar property would hold also in the full theory.…”

Section: Introductionmentioning

confidence: 99%

Challenges in recovering a consistent cosmology from the effective dynamics of loop quantum gravity

2019

View full text Add to dashboard Cite

We reexamine a set of existing procedures aimed at recovering the effective description of the dynamics of LQG in the context of cosmological solutions. In particular, the studies of those methods, to which the choice of cuboidal graphs and graph-preserving Hamiltonian is central, result in the formulation of a set of no-go statements, severely limiting the possibility of recovering a physically consistent effective dynamics this way.1 In LQG, the space of states consists of cylindrical functions supported on graphs. A graph-preserving operator is an operator which preserves the subspace of cylindrical functions supported on each given graph [17]. 2 The most popular convention is: v = 2πG γ √ ∆p 3/2 and b = c ∆/p, where ∆ is the so-called "area-gap" [15].

show abstract

Bouncing evolution in a model of loop quantum gravity

Cited by 27 publications

References 46 publications

Effective dynamics from coherent state path integral of full loop quantum gravity

Effective dynamics from coherent state path integral of full loop quantum gravity

Innermost stable circular orbit and shadow of the 4D Einstein–Gauss–Bonnet black hole

Challenges in recovering a consistent cosmology from the effective dynamics of loop quantum gravity

Contact Info

Product

Resources

About