Article
Astronomy & Astrophysics
M. Nilton, J. Furtado, G. Alencar
Summary: In this paper, we investigate the traversability of a wormhole in the context of asymptotically safe gravity (ASG) for both spherical and pseudospherical cases. We analyze the throat of the wormhole using a specific cutoff function and generalize the previous study by considering a position-dependent classical state parameter and an ASG improvement of the source. Our findings suggest that traversability of the wormhole is highly dependent on its parameters and the type of matter used.
Article
Astronomy & Astrophysics
J. Chojnacki, J. Krajecka, J. H. Kwapisz, O. Slowik, A. Strag
Summary: This article explores the relationship between eternal inflation and the asymptotic safety hypothesis in other approaches to quantum gravity. It reveals that there is no tension between eternal inflation and asymptotic safety in both the matter and gravitational sectors, contrary to string theory. Additionally, it suggests that eternal inflation is not possible within the range of applicability of effective field quantum gravity theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Biao Zhou, Askar B. Abdikamalov, Dimitry Ayzenberg, Cosimo Bambi, Sourabh Nampalliwar, Ashutosh Tripathi
Summary: Asymptotically safe quantum gravity theory builds on the framework of quantum field theory, with a new rotating black hole metric proposed to extend its applications. X-ray reflection spectroscopy is used to observe and test the theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Alessio Baldazzi, Kevin Falls, Renata Ferrero
Summary: This paper presents an approach to compute the renormalisation group flow of relational observables in quantum gravity, with the application example of four scalar fields coupled to gravity. The approach is applicable to a wide range of relational observables in different physical coordinate systems, and evaluates their scaling dimensions at fixed points.
Article
Astronomy & Astrophysics
Oem Trivedi, Maxim Khlopov
Summary: This study explores the formation of cosmological singularities in asymptotically safe cosmology using renormalization group approaches. It discovers special conditions and forms of cosmological singularities in this cosmology, which differ significantly from standard cosmology and do not require free parameters. Additionally, conventional singularity removal methods are ineffective in this cosmology.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
M. Nilton, J. Furtado, G. Alencar, R. R. Landim
Summary: In this study, we examine a type of wormhole solutions known as generalized Ellis-Bronnikov wormholes in the framework of asymptotically safe gravity (ASG). These solutions are characterized by two parameters: an even number n and the wormhole throat radius rt. By utilizing three curvature scalars in the ASG approach, namely, the Ricci scalar, squared Ricci, and the Kretschmann scalar, we investigate the nature of matter in the throat and nearby regions of these generalized solutions with n > 2. Our findings reveal that the ASG only introduces corrections in the matter at the throat for the case of n = 4. Furthermore, we demonstrate that exotic matter is always required for the squared Ricci and the Kretschmann cases, whereas for the Ricci scalar case, ordinary matter is permissible at the throat. Consequently, the generalized Ellis-Bronnikov wormhole offers the possibility of having ordinary matter at the throat within the context of asymptotically safe gravity.
Article
Astronomy & Astrophysics
Gustavo P. de Brito, Antonio D. Pereira, Arthur F. Vieira
Summary: The renormalization group flow of unimodular quantum gravity was studied with different truncations of the effective action, searching for nontrivial fixed-point solutions for polynomial expansions. The system included beta functions for gravitational couplings, anomalous dimensions of graviton and ghosts, and investigated the impact of different endomorphism parameter choices on fixed-point structure. Evidence for nontrivial fixed points was found, with the f(R) truncation showing better convergence properties, and compatibility with the Standard Model and its extensions was explored when matter fields were included.
Article
Astronomy & Astrophysics
Geova Alencar, Matheus Nilton
Summary: This paper analyzes the Schwarzschild-like wormhole in the Asymptotically Safe Gravity scenario, examining the radial energy conditions and potential types of cosmologic matter present. The study shows that in specific cases, the energy conditions are satisfied at the throat, but not in general, and that phantom-like matter may exist in all scenarios. Quantum gravity corrections due to ASG are found to imply the presence of phantom-like matter for both Schwarzschild and Schwarzschild-like wormholes, suggesting a consistent presence of phantom fluid in this context.
Article
Astronomy & Astrophysics
G. Alencar, V. B. Bezerra, C. R. Muniz, H. S. Vieira
Summary: This paper investigates the simplest wormhole solution in the context of asymptotically safe gravity at the Planck scale. It is found that asymptotic safety guarantees the Ellis-Bronnikov wormhole can satisfy radial energy conditions and requires exotic sources of matter to generate the wormhole spacetime. Furthermore, the paper speculates on the presence of phantom-like matter in wormholes in the ASG context or more general quantum gravity scenarios.
Article
Astronomy & Astrophysics
Jesse Daas, Wouter Oosters, Frank Saueressig, Jian Wang
Summary: By setting up a consistent background field formalism, we conducted a detailed study on the renormalization group flow of gravity coupled to Nf Dirac fermions, identifying two infinite families of interacting RG fixed points. These fixed points correspond to quasi-chiral and non-chiral fixed points, showing potential for high-energy completion and becoming weakly coupled in the large Nf-limit.
Article
Physics, Multidisciplinary
Rituparna Mandal, Sunandan Gangopadhyay, Amitabha Lahiri
Summary: In this study, we examine FLRW cosmology with quantum gravitational corrections using the exact renormalization group flow of the effective action for gravity. By calculating the quantum-corrected scale factor, energy density, and entropy production at late times with different choices of cut-off functions, we find that the observed late time cosmologies depend on the chosen cut-off identifications. Additionally, our approach involves using the running Newton constant G(k) in the definition of the energy-momentum tensor and imposing the covariant conservation identity of the Einstein tensor, leading to different quantum corrections compared to a scale-independent Newton constant.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
H. Garcia-Compean, D. Mata-Pacheco
Summary: The study examines the vacuum transition probabilities for anisotropic universes with a scalar field potential, adapting a formalism to calculate decay rates for various superspace models. It is found that increasing anisotropy tends to decrease the transition probability, with the isotropic limit resulting in the flat FLRW outcome.
Article
Astronomy & Astrophysics
M. Fabbrichesi, C. M. Nieto, A. Tonero, A. Ugolotti
Summary: This study involves adding new vectorlike fermions at the TeV scale, embedding the model into an SU(5) grand unified theory, achieving gauge coupling unification, and avoiding Landau poles in the U(1) gauge and Higgs couplings.
Article
Astronomy & Astrophysics
Christof Wetterich
Summary: This study computes the effective potential for scalar fields in asymptotically safe quantum gravity, finding that the scaling potential and other scaling functions can generalize the fixed point values of renormalizable couplings, and providing evidence for phenomena such as spontaneous symmetry breaking induced by non-vanishing gauge couplings.
Article
Astronomy & Astrophysics
Pietro Dona
Summary: Local flatness is a shared property of all spin foam models, ensuring that the building blocks of the theory are flat by requiring locally-trivial parallel transport. In the context of simplicial Lorentzian spin foam theory, local flatness is shown to be the main factor in the emergence of geometry, independent of the specific spin foam model details. The asymptotic analysis of the Engle-Pereira-Rovelli-Livine spin foam amplitudes in the regime of large quantum numbers is discussed, highlighting the interplay with local flatness.
Article
Physics, Particles & Fields
W. B. Houthoff, A. Kurov, F. Saueressig
EUROPEAN PHYSICAL JOURNAL C
(2017)
Article
Physics, Particles & Fields
Jorn Biemans, Alessia Platania, Frank Saueressig
JOURNAL OF HIGH ENERGY PHYSICS
(2017)
Article
Physics, Multidisciplinary
Alessia Platania, Frank Saueressig
FOUNDATIONS OF PHYSICS
(2018)
Review
Physics, Multidisciplinary
Giulia Gubitosi, Chris Ripken, Frank Saueressig
FOUNDATIONS OF PHYSICS
(2019)
Article
Physics, Multidisciplinary
Lando Bosma, Benjamin Knorr, Frank Saueressig
PHYSICAL REVIEW LETTERS
(2019)
Article
Astronomy & Astrophysics
Benjamin Knorr, Chris Ripken, Frank Saueressig
CLASSICAL AND QUANTUM GRAVITY
(2019)
Article
Astronomy & Astrophysics
Jesse Daas, Wouter Oosters, Frank Saueressig, Jian Wang
Article
Astronomy & Astrophysics
Alfio Bonanno, Amir-Pouyan Khosravi, Frank Saueressig
Summary: A common feature in regular black hole spacetimes is the presence of a Cauchy horizon, which is believed to make the geometry unstable due to the mass-inflation effect. This study examines the dynamics of this effect, taking into account the mass-loss of the black hole caused by Hawking radiation. The results show that the Hawking flux has a profound impact on the mass-inflation instability, either weakening the effect significantly or even eliminating it entirely.
Article
Astronomy & Astrophysics
Frank Saueressig, Amir Khosravi
Summary: This article studies the impact of the intriguing feature shared by many quantum gravity programs, the dynamic decrease of the spectral dimension, on the energy loss of static, spherically symmetric black holes due to Hawking radiation. The study shows that the decrease in the spectral dimension renders the luminosity of a black hole finite, but this mechanism is insufficient to generate long-lived black hole remnants.
Article
Astronomy & Astrophysics
Alfio Bonanno, Amir-Pouyan Khosravi, Frank Saueressig
Summary: This study analyzes the dynamics of regular black holes and identifies crucial features that tame the growth of the mass function and reduce the curvature singularity at the Cauchy horizon. It is explicitly demonstrated that the regular black hole solutions proposed by Hayward and obtained from Asymptotic Safety satisfy these properties.
Article
Physics, Particles & Fields
Tom Draper, Benjamin Knorr, Chris Ripken, Frank Saueressig
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Physics, Multidisciplinary
Tom Draper, Benjamin Knorr, Chris Ripken, Frank Saueressig
PHYSICAL REVIEW LETTERS
(2020)
Article
Astronomy & Astrophysics
Jorn Biemans, Alessia Platania, Frank Saueressig
Article
Astronomy & Astrophysics
Alfio Bonanno, Frank Saueressig
COMPTES RENDUS PHYSIQUE
(2017)
Proceedings Paper
Astronomy & Astrophysics
Benjamin Koch, Carlos Contreras, Paola Rioseco, Frank Saueressig
1ST KARL SCHWARZSCHILD MEETING ON GRAVITATIONAL PHYSICS
(2016)
