The spectral dimension in 2D CDT gravity coupled to scalar fields

Ambjørn, J.; Görlich, Andrzej; Jurkiewicz, J.; Zhang, Honggang

doi:10.1142/s0217732315500777

Cited by 9 publications

(6 citation statements)

References 49 publications

(40 reference statements)

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“…This expected behavior seems to be matched by the results of very recent 2D Monte-Carlo simulations of CDT coupled to more than one massive scalar field [106][107][108]. It was found that, above a certain value of their mass, the dynamics of the CDT+matter system is significantly different from the massless case.…”

Section: Jhep02(2016)167supporting

confidence: 76%

The unitary conformal field theory behind 2D Asymptotic Safety

Nink

Reuter

2016

J. High Energ. Phys.

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Being interested in the compatibility of Asymptotic Safety with Hilbert space positivity (unitarity), we consider a local truncation of the functional RG flow which describes quantum gravity in d > 2 dimensions and construct its limit of exactly two dimensions. We find that in this limit the flow displays a nontrivial fixed point whose effective average action is a non-local functional of the metric. Its pure gravity sector is shown to correspond to a unitary conformal field theory with positive central charge c = 25. Representing the fixed point CFT by a Liouville theory in the conformal gauge, we investigate its general properties and their implications for the Asymptotic Safety program. In particular, we discuss its field parametrization dependence and argue that there might exist more than one universality class of metric gravity theories in two dimensions. Furthermore, studying the gravitational dressing in 2D asymptotically safe gravity coupled to conformal matter we uncover a mechanism which leads to a complete quenching of the a priori expected Knizhnik-Polyakov-Zamolodchikov (KPZ) scaling. A possible connection of this prediction to Monte Carlo results obtained in the discrete approach to 2D quantum gravity based upon causal dynamical triangulations is mentioned. Similarities of the fixed point theory to, and differences from, non-critical string theory are also described. On the technical side, we provide a detailed analysis of an intriguing connection between the Einstein-Hilbert action in d > 2 dimensions and Polyakov's induced gravity action in two dimensions.

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Section: Jhep02(2016)167supporting

confidence: 76%

The unitary conformal field theory behind 2D Asymptotic Safety

Nink

Reuter

2016

J. High Energ. Phys.

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“…To bridge the gap towards particle-physics phenomenology, the inclusion of matter fields could be fruitful, and has been explored, e.g., in [256,257]. In the related Euclidean dynamical triangulations approach, gauge fields were studied early on [258] and fermionic matter fields have been introduced [259], with first indications that chiral symmetry -protecting the lightness of fermions compared to the Planck scale -could remain intact, similarly to the continuum approach to asymptotic safety [28].…”

Section: Causal Dynamical Triangulationsmentioning

confidence: 99%

Quantum gravity phenomenology at the dawn of the multi-messenger era -- A review

Addazi,

Alvarez-Muniz,

Batista

et al. 2021

Preprint

107

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The exploration of the universe has recently entered a new era thanks to the multi-messenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic messengers (photons, neutrinos, cosmic rays and gravitational waves) from numerous origins. They give us information about their sources in the universe and the properties of the intergalactic medium. Moreover, multi-messenger astronomy opens up the possibility to search for phenomenological signatures of quantum gravity. On the one hand, the most energetic events allow us to test our physical theories at energy regimes which are not directly accessible in accelerators; on the other hand, tiny effects in the propagation of very high energy particles could be amplified by cosmological distances. After decades of merely theoretical investigations, the possibility of obtaining phenomenological indications of Planck-scale effects is a revolutionary step in the quest for a quantum theory of gravity, but it requires cooperation between different communities of physicists (both theoretical and experimental). This review, prepared within the COST Action CA18108 "Quantum gravity phenomenology in the multi-messenger approach", is aimed at promoting this cooperation by giving a state-of-the art account of the interdisciplinary expertise that is needed in the effective search of quantum gravity footprints in the production, propagation and detection of cosmic messengers.

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“…The results can be contrasted with EDT, where matter does not seem to influence the geometry in a significant way [45,46,47,48,49]. In two-dimensional CDT models, adding a coupling to scalar [89,90,91,92,93] and gauge [94] fields did result in a notable change of the geometry, as described in the articles cited. However, no substantial impact of scalar field on spacetime geometry or the phase diagram was shown in four-dimensional CDT in studies previous to the articles on which this chapter is based.…”

Section: Dynamical Scalar Fieldsmentioning

confidence: 97%