Asymptotically safe gravity with fermions

Daas, Jesse; Oosters, Wouter; Saueressig, Frank; Wang, Jian

doi:10.1016/j.physletb.2020.135775

Cited by 36 publications

(39 citation statements)

References 64 publications

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“…It is reassuring to see that quantum fluctuations of the metric do not support the same kind of chiral-symmetry breaking mechanism as is triggered by spin-one gauge fields or Yukawa interactions with scalars [1][2][3][4][5][6][7][8][9]. For both latter cases, the gauge or Yukawa couplings simply have to increase beyond a certain threshold which renders chiral-symmetry breaking in these scenarios a rather universal strong-coupling feature.…”

Section: Introductionmentioning

confidence: 99%

Curvature bound from gravitational catalysis

Gies

Martini

2018

Phys. Rev. D

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We determine bounds on the curvature of local patches of spacetime from the requirement of intact longrange chiral symmetry. The bounds arise from a scale-dependent analysis of gravitational catalysis and its influence on the effective potential for the chiral order parameter, as induced by fermionic fluctuations on a curved spacetime with local hyperbolic properties. The bound is expressed in terms of the local curvature scalar measured in units of a gauge-invariant coarse-graining scale. We argue that any effective field theory of quantum gravity obeying this curvature bound is safe from chiral symmetry breaking through gravitational catalysis and thus compatible with the simultaneous existence of chiral fermions in the low-energy spectrum. With increasing number of dimensions, the curvature bound in terms of the hyperbolic scale parameter becomes stronger. Applying the curvature bound to the asymptotic safety scenario for quantum gravity in four spacetime dimensions translates into bounds on the matter content of particle physics models.

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Section: Introductionmentioning

confidence: 99%

Curvature bound from gravitational catalysis

Gies

Martini

2018

Phys. Rev. D

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“…The seminal paper by Reuter [11] indeed showed evidence for the existence of a fixed point in four dimensions within a minimal approximation. Since then, a growing body of work based on evermore improved approximations solidifies the picture, even when matter is included [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73]. Phenomenological applications have been discussed in [74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91].…”

Section: Introductionmentioning

confidence: 99%

The derivative expansion in asymptotically safe quantum gravity: general setup and quartic order

Knorr

2021

SciPost Phys. Core

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We present a general framework to systematically study the derivative expansion of asymptotically safe quantum gravity. It is based on an exact decoupling and cancellation of different modes in the Landau limit, and implements a correct mode count as well as a regularisation based on geometrical considerations. It is applicable independent of the truncation order. To illustrate the power of the framework, we discuss the quartic order of the derivative expansion and its fixed point structure as well as physical implications.

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“…Notwithstanding, quantum effects in gravity can be described through an asymptotically safe quantum field theory, which is UV complete [21][22][23][24]. The existence of such a fixed point for the gravity re-normalization group flow is verified from several methods and in various scenarios [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Its physical applications are explored in [43][44][45][46][47][48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Ellis–Bronnikov Wormholes in Asymptotically Safe Gravity

et al. 2021

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In this paper, we investigate the simplest wormhole solution—the Ellis–Bronnikov one—in the context of the asymptotically safe gravity (ASG) at the Planck scale. We work with three models, which employ the Ricci scalar, Kretschmann scalar, and squared Ricci tensor to improve the field equations by turning the Newton constant into a running coupling constant. For all the cases, we check the radial energy conditions of the wormhole solution and compare them with those that are valid in general relativity (GR). We verified that asymptotic safety guarantees that the Ellis–Bronnikov wormhole can satisfy the radial energy conditions at the throat radius, r0, within an interval of values of the latter, which is quite different from the result found in GR. Following this, we evaluate the effective radial state parameter, ω(r), at r0, showing that the quantum gravitational effects modify Einstein’s field equations in such a way that it is necessary to have a very exotic source of matter to generate the wormhole spacetime–phantom or quintessence-like matter. This occurs within some ranges of the throat radii, even though the energy conditions are or are not violated there. Finally, we find that, although at r0 we have a quintessence-like matter, upon growing r, we inevitably came across phantom-like regions. We speculate whether such a phantom fluid must always be present in wormholes in the ASG context or even in more general quantum gravity scenarios.

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Asymptotically safe gravity with fermions

Cited by 36 publications

References 64 publications

Curvature bound from gravitational catalysis

Curvature bound from gravitational catalysis

The derivative expansion in asymptotically safe quantum gravity: general setup and quartic order

Ellis–Bronnikov Wormholes in Asymptotically Safe Gravity

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