Fri - 04/28/23

Periodic orbits and their gravitational wave radiations in a polymer black hole in loop quantum gravity

  • Authors: Ze-Yi Tu, Tao Zhu, Anzhong Wang
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
  • Arxiv link: https://arxiv.org/abs/2304.14160
  • Abstract This article provides a detailed investigation into the motion of the surrounding particles around a polymer black hole in loop quantum gravity (LQG). Using effective potential, the critical bound orbits and innermost stable circular orbits (ISCO) are analyzed. The study finds that the radii and angular momentum of the critical bound orbits decrease with an increase in the parameter $A_\lambda$ which labels the LQG effects, while the energy and angular momentum of the ISCO also decreases with an increase in $A_\lambda$. Based on these findings, we then explore the periodic orbits of the polymer black hole in LQG using rational numbers composed of three integers. Our results show that the rational numbers increase with the energy of particles and decrease with the increase of angular momentum based on a classification scheme. Moreover, compared to a Schwarzschild black hole, the periodic orbits in a polymer black hole in LQG consistently have lower energy, providing a potential method for distinguishing a polymer black hole in LQG from a Schwarzschild black hole. Finally, we also examine the gravitational wave radiations of the periodic orbits of a test object which orbits a supermassive polymer black hole in LQG, which generates intricate GW waveforms that can aid in exhibiting the gravitational structure of the system.

There is no new related paper today

Thu - 04/27/23

There is no new related paper today

Curvature effects in the spectral dimension of spin foams

  • Authors: Alexander Jercher, Sebastian Steinhaus, Johannes Thürigen
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2304.13058
  • Abstract It has been shown in [1] that a class of restricted spin foam models can feature a reduced spectral dimension of space-time. However, it is still an open question how curvature affects the flow of the spectral dimension. To answer this question, we consider another class of restricted spin foam models, so called spin foam frusta, which naturally exhibit oscillating amplitudes induced by curvature, as well as an extension of the parameter space by a cosmological constant. Numerically computing the spectral dimension of $1$-periodic frusta geometries using extrapolated quantum amplitudes, we find that quantum effects lead to a small change of spectral dimension at small scales and an agreement to semi-classical results at larger scales. Adding a cosmological constant $\Lambda$, we find additive corrections to the non-oscillating result at the diffusion scale $\tau\sim 1/\sqrt{\Lambda}$. Extending to $2$-periodic configurations, we observe a reduced effective dimension, the form of which sensitively depends on the values of the gravitational constant $G$ and the cosmological constant $\Lambda$. We provide an intuition for our results based on an analytical estimate of the spectral dimension. Furthermore, we present a simplified integrable model with oscillating measure that qualitatively explains the features found numerically. We argue that there exists a phase transition in the thermodynamic limit which crucially depends on the parameters $G$ and $\Lambda$. The dependence on $G$ and $\Lambda$ presents an exciting opportunity to infer phenomenological insights about quantum geometry from measurement of the spectral dimension, in principle. [1]: S. Steinhaus and J. Th"urigen, Emergence of Spacetime in a restricted Spin-foam model, Phys. Rev. D 98 (2018) 026013

Exotic Field Theories for (Hybrid) Fracton Phases from Imposing Constraints in Foliated Field Theory

  • Authors: Ryan C. Spieler
  • Subjects: High Energy Physics - Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el)
  • Arxiv link: https://arxiv.org/abs/2304.13067
  • Abstract Fracton phases of matter are gapped phases of matter that, by dint of their sensitivity to UV data, demand non-standard quantum field theories to describe them in the IR. Two such approaches are foliated quantum theory and exotic field theory. In this paper, we explicitly construct a map from one to the other and work out several examples. In particular, we recover the equivalence between the foliated and exotic fractonic BF theories recently demonstrated at the level of operator correspondence. We also demonstrate the equivalence of toric code layers and the anisotropic model with lineons and planons to the foliated BF theory with one and two foliations, respectively. Finally, we derive new exotic field theories that provide simple descriptions of hybrid fracton phases from foliated field theries known to do so. Our results both provide new examples of exotic field theories and pave the way toward their systematic construction from foliated field theories.

  1. [2304.13263] - Strong gravitational lensing of rotating regular black holes in non-minimally coupled Einstein-Yang-Mills theory - Ruanjing Zhang, Jiliang Jing, Zhipeng Peng, Qihong Huang

  2. [2304.13650] - Solving 3d Gravity with Virasoro TQFT - Scott Collier, Lorenz Eberhardt, Mengyang Zhang

Wed - 04/26/23

There is no new related paper today

There is no new related paper today

  1. [2304.12750] - Black hole hairs in scalar-tensor gravity (and lack thereof) - Lodovico Capuano, Luca Santoni, Enrico Barausse

  2. [2304.12767] - Lorentz Violation in Finsler Geometry - Jie Zhu, Bo-Qiang Ma

  3. [2304.12349] - Stochastic Description of Near-Horizon Fluctuations in Rindler-AdS - Yiwen Zhang, Kathryn M. Zurek

Tue - 04/25/23

There is no new related paper today

There is no new related paper today

  1. [2304.11578] - A non-singular bouncing cosmology in $ f(R,T) $ gravity - J. K. Singh, Shaily, Akanksha Singh, Aroonkumar Beesham, Hamid Shabani

  2. [2304.12024] - Summing over Non-singular Paths in Quantum Cosmology - Hiroki Matsui

  3. [2304.11430] - Holographic n-partite Information in Hyperscaling Violating Geometry - Xin-Xiang Ju, Teng-Zhou Lai, Ya-Wen Sun, Yuan-Tai Wang

  4. [2304.11813] - A note on lattice description of generalized symmetries in $SU(N)/\mathbb{Z}_N$ gauge theories - Motokazu Abe, Okuto Morikawa, Soma Onoda

Mon - 04/24/23

Emergent Gravity from the Entanglement Structure in Group Field Theory

  • Authors: Jinglong Liu, Stephon Alexander, Antonino Marciano, Roman Pasechnik
  • Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)
  • Arxiv link: https://arxiv.org/abs/2304.10865
  • Abstract We couple a scalar field encoding the entanglement between manifold sites to group field theory (GFT). The scalar field provides a relational clock that enables the derivation of the Hamiltonian of the system from the GFT action. Inspecting this Hamiltonian, we show that a theory of emergent gravity arises, and that the theory is equivalent to the Ashtekar variables’ formulation of general relativity. The evolution of the system in GFT is a renormalization group (RG) flow, which corresponds to a simplified Ricci flow, the generator of which is the Hamiltonian, and the corresponding flow equation is regulated by the Shroedinger equation. As a consequence of the quantization procedure, the Hamiltonian is recovered to be non-Hermitian, and can be related to the complex action formalism, in which the initial conditions and the related future evolution of the systems are dictated by the imaginary part of the action.

There is no new related paper today

  1. [2304.10868] - Gravitationally modulated quantum correlations: Discriminating classical and quantum models of ultra-compact objects with Bell nonlocality - Luciano Petruzziello, Fabrizio Illuminati

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