Archived weekly pre-prints 22-01-31

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[2201.11402] - Nonvanishing gravitational contribution to matter beta functions for vanishing dimensionful regulators - Gustavo P. de Brito, Astrid Eichhorn
[2201.11575] - On Unitarity of Tree-Level String Amplitudes - Nima Arkani-Hamed, Lorenz Eberhardt, Yu-tin Huang, Sebastian Mizera
[2201.11658] - The Universe as a Quantum Encoder - Jordan Cotler, Andrew Strominger
[2201.11730] - The Page Curve for Reflected Entropy - Chris Akers, Thomas Faulkner, Simon Lin, Pratik Rath

There is no new related paper today

[2201.10870] - Fractional Klein-Gordon Equation on AdS$_{2+1}$ - Pablo Basteiro, Janine Elfert, Johanna Erdmenger, Haye Hinrichsen

Authors: Yun-Long Liu, Zhao-Qing Feng, Xiang-Dong Zhang
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2201.10202
Abstract A new polymer black hole solution in loop quantum gravity was proposed recently. The difference between the polymer black hole and Schwarzschild black hole is captured by a quantum parameter $A$. In order to get the constraints on parameter $A$, we consider the observational constraints imposed on $A$ by using the Solar System experiments and calculate the deflection of light, Shapiro time delay, perihelion precession and obtain the effects associated with parameter $A$. Moreover, the parameterized post-Newtonian approach of this loop quantum gravity black hole was also carried out. It turns out the tightest constraint on $A$ can be improved to $0<A<4.0\times10^{-6}$.

Authors: Courtney Allen, Florian Girelli, Sebastian Steinhaus
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2201.09902
Abstract We present the first numerical calculation of the 4D Euclidean spin foam vertex amplitude for vertices with hypercubic combinatorics. Concretely, we compute the amplitude for coherent boundary data peaked on cuboid and frustum shapes. We present the numerical algorithms to explicitly compute the vertex amplitude and compare the results in different cases to the semi-classical approximation of the amplitude. Overall we find good qualitative agreement of the amplitudes and evidence of convergence of the asymptotic formula to the full amplitude already at fairly small spins, yet also differences in the frequency of oscillations and a phase shift absent in the 4-simplex case. However, due to rapidly growing numerical costs, we cannot reach sufficiently high spins to prove agreement of both amplitudes. Lastly, this setup allows us to explore non-uniform vertex amplitudes, where some representations are small while others are large; we find indications that scenarios might exist in which the semi-classical amplitude is a valid approximation even if some spins remain small. This suggests that the transition of the quantum to the semi-classical regime (for a single vertex amplitude) is intricate.

[2201.10554] - Novel aspects of integrability for NLSMs in symmetric spaces - Dimitrios Katsinis

Authors: J.Manuel García-Islas
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph)
Arxiv link: https://arxiv.org/abs/2201.09143
Abstract Loop quantum gravity is a physical theory which aims at unifying general relativity and quantum mechanics. It takes general relativity very seriously and modifies it via a quantisation. General relativity describes gravity in terms of geometry. Therefore, quantising such theory must be equivalent to quantising geometry and that is what loop quantum gravity does. This sounds like a mathematical task as well. This is why in this paper we will present the mathematics of loop quantum gravity. We will do it from a mathematician point of view. This paper is intended to be an introduction to loop quantum gravity for postgraduate students of physics and mathematics. In this work we will restrict ourselves to the three dimensional case.

Authors: Daniel del-Corral, Javier Olmedo
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2201.09584
Abstract We study the quasinormal frequencies of three effective geometries of nonrotating regular black holes derived from loop quantum gravity. Concretely, we consider the Ashtekar-Olmedo-Singh and two Gambini-Olmedo-Pullin prescriptions. We compute the quasinormal frequencies of axial and polar perturbations adopting a WKB method. We show that they differ from those of classical general relativity and, more importantly, that isospectrality is broken. Nevertheless, these deviations are tiny, even for microscopic black holes, and they decay following an inverse power law of the size of the mass of the black holes. For the sake of completeness, we also analyze scalar and vector perturbations, reaching similar conclusions.

There is no new related paper today

There is no new related paper today

[2201.08405] - Toolkit for scalar fields in universes with finite-dimensional Hilbert space - Oliver Friedrich, Ashmeet Singh, Olivier Doré
[2201.08415] - Echoes of charged black-bounce spacetimes - Shurui Wu, Z. W. Long, Zhaoyi Xu, Dong Liu, Yi Yang
[2201.08395] - Canonical Purification of Evaporating Black Holes - Netta Engelhardt, Åsmund Folkestad
[2201.08410] - The Hilbert Space of large $N$ Chern-Simons matter theories - Shiraz Minwalla, Amiya Mishra, Naveen Prabhakar, Tarun Sharma