Article
Astronomy & Astrophysics
Mingzhe Li, Haomin Rao, Yeheng Tong
Summary: This paper restores the local Lorentz symmetry of a gravity model by giving up the Weitzenbock condition on the spin connection, and applies the new version of the model to the universe with general Friedmann-Robertson-Walker background, obtaining some new results.
Article
Physics, Multidisciplinary
A. A. Araujo Filho, J. A. A. S. Reis
Summary: In this study, the interaction of quantum gases in Lorentz-violating scenarios, considering both boson and fermion sectors, was investigated. Different operators were examined for their implications on the system, leading to varying effects in low and high-temperature regimes. Notably, even in the presence of Lorentz violation, the system exhibits extensive characteristics in terms of particle number, entropy, and energy.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Physics, Multidisciplinary
Haobo Yan
Summary: The role of a Lorentz-violating term in the outcomes of kink scattering in the phi(6) model is investigated using the Fourier spectral method. The impacts of this term on critical velocities, the location of two-bounce windows, and maximal values of energy densities are analyzed. Novel features of kink-antikink collisions are discussed, along with interactions between three and four kinks.
Article
Astronomy & Astrophysics
Ramil N. Izmailov, Kamal K. Nandi
Summary: A possible method for observing quantum gravity effects at low energy scales is to introduce spontaneous Lorentz violation in new models of gravity. This paper examines the effects of Lorentz violation corrections in bumblebee gravity and how they differ from general relativity, particularly in the strong field lensing properties of Schwarzschild-like black holes.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Astronomy & Astrophysics
L. H. C. Borges, A. F. Ferrari
Summary: This paper investigates the interactions between stationary electromagnetic sources in the minimal and nonminimal CPT-odd photon sector of the Standard Model Extension (SME). The study focuses on searching for physical phenomena that are not present in Maxwell electrodynamics. The effects of Lorentz violation caused by different terms are analyzed, and calculations are performed to determine the electromagnetic field and bound states in the presence of point-like charges, Dirac strings, and dipoles. The physical relevance of the results in atomic systems is explored by using constraints on the Lorentz violation parameters and overestimating the background vectors based on experimental data.
MODERN PHYSICS LETTERS A
(2022)
Article
Physics, Multidisciplinary
Bruno Arderucio Costa, Yuri Bonder, Benito A. Juarez-Aubry
Summary: Several approaches to quantum gravity suggest violations of Lorentz symmetry, and this article uses a concrete Lorentz-violating quantum field theory to study different inertial vacua. It finds that the vacua in different inertial frames are unitarily inequivalent, and particles of arbitrarily high momenta can appear in one frame but not in others. However, the article also demonstrates that inertial Unruh-De Witt detectors are insensitive to these effects, and discusses the Hadamard condition for this Lorentz-violating theory.
Article
Astronomy & Astrophysics
Francesco Cianfrani
Summary: This research presents a manifestly Lorentz-covariant formulation of loop quantum gravity using finite-dimensional representations of the Lorentz group, while accounting for discrete symmetries like parity and time-reversal, and establishing a link with Wigner classification of particles. The resulting quantum model can be seen as LQG-like with the internal SU(2) circle times SU(2) group, and it is free of the Immirzi parameter, with the scalar constraint being just the Euclidean part.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
B. Altschul, L. C. T. Brito, J. C. C. Felipe, S. Karki, A. C. Lehurm, A. Yu. Petrov
Summary: In this work, we investigate a Lorentz-violating scalar quantum chromodynamics theory with an arbitrary non-Abelian gauge group, which falls under the class of models encompassed by the standard model extension framework. By calculating the divergent quantum corrections at the lowest order in the theory's Lorentz violation parameters, including the renormalization group β-functions, we demonstrate that the Lorentz-violating sector exhibits scale invariance when certain couplings satisfy a particular relation.
Article
Physics, Multidisciplinary
Zhi-E. Liu, Jie Zhang, Shu-Zheng Yang
Summary: In accordance with Lorentz-violating theory, the dynamical equation of Dirac particles is altered in the Kinnersley black hole, showcasing new characteristics of Hawking quantum tunneling radiation. The Hawking temperature expression of the Kinnersley black hole has been revised for improved accuracy.
FRONTIERS IN PHYSICS
(2021)
Article
Physics, Particles & Fields
Ibrahima Bah, Yiming Chen, Juan Maldacena
Summary: We examine the scattering of spherically symmetric shells in asymptotically AdS(D) spacetimes at high energy and ultra-relativistic speeds. Specifically, we analyze an exclusive amplitude where one shell enters and another shell exits, with different global symmetry charges in the effective gravity theory. We investigate a simple wormhole configuration that calculates the square of the amplitude and study its properties.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Multidisciplinary
J. M. Carmona, J. L. Cortes, J. J. Relancio, M. A. Reyes, A. Vincueria
Summary: Ultra-high-energy physics is about to enter a new era with the impressive results of recent experiments, which have the potential to test deviations from special relativity. This study considers modifications due to relativistic deformed kinematics and investigates the mean free path of high-energy photons interacting with low-energy photons of the cosmic microwave background. Current or future experiments may be sensitive enough to detect deviations from special relativity.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Physics, Particles & Fields
Sapan Karki, Brett Altschul
Summary: This article investigates redundancies of description in effective quantum field theories that allow for the possibility of Lorentz symmetry violation. The study shows that different renormalization schemes may lead to different expressions for the renormalization group beta-functions, but the renormalization group scaling of physically observable quantities appears not to be affected by this scheme dependence.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Jacopo Mazza, Stefano Liberati
Summary: There is increasing evidence that Horava gravity is a viable quantum theory of gravity. This suggests that gravitational collapse in the non-projectable version of the theory should result in geometries without space-time singularities. Previous studies have identified different classes of such geometries, including regular black holes, non-connected black holes with wormhole mouths, and horizonless compact objects. This study focuses on a singular black hole in the low-energy limit of non-projectable Horava gravity, exploring examples of its regularizations within all viable classes. These examples are the first instances of black holes with inner universal horizons, black bounces, and stars with a de Sitter core in the context of Lorentz-violating theories of gravity.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
T. Mariz, R. Martinez, J. R. Nascimento, A. Yu Petrov
Summary: This paper investigates the Lorentz-violating extended QED with nonminimal dimension-5 additive CPT-odd terms, focusing on the generation of CFJ term and its higher-derivative counterparts, demonstrating the vanishing of CFJ term in dimensional regularization and the elimination of higher-derivative divergent contributions by considering a given proportionality between coefficients.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Mathematics, Applied
David Escors, Grazyna Kochan
Summary: This study tests whether space quantization on the order of Planck length could still be compatible with Lorentz invariance through the application of a covariant geometric uncertainty principle (GeUP) as a constraint over geodesics in FRW geometries. The results are in agreement with space-time quantization on the expected length orders, according to quantum gravity theories, and within experimental constraints on putative LIV.
Review
Physics, Nuclear
A. Addazi, J. Alvarez-Muniz, R. Alves Batista, G. Amelino-Camelia, V Antonelli, M. Arzano, M. Asorey, J-L Atteia, S. Bahamonde, F. Bajardi, A. Ballesteros, B. Baret, D. M. Barreiros, S. Basilakos, D. Benisty, O. Birnholtz, J. J. Blanco-Pillado, D. Blas, J. Bolmont, D. Boncioli, P. Bosso, G. Calcagni, S. Capozziello, J. M. Carmona, S. Cerci, M. Chernyakova, S. Clesse, J. A. B. Coelho, S. M. Colak, J. L. Cortes, S. Das, V D'Esposito, M. Demirci, M. G. Di Luca, A. di Matteo, D. Dimitrijevic, G. Djordjevic, D. Dominis Prester, A. Eichhorn, J. Ellis, C. Escamilla-Rivera, G. Fabiano, S. A. Franchino-Vinas, A. M. Frassino, D. Frattulillo, S. Funk, A. Fuster, J. Gamboa, A. Gent, L. A. Gergely, M. Giammarchi, K. Giesel, J-F Glicenstein, J. Gracia-Bondia, R. Gracia-Ruiz, G. Gubitosi, E. Guendelman, I Gutierrez-Sagredo, L. Haegel, S. Heefer, A. Held, F. J. Herranz, T. Hinderer, J. I. Illana, A. Ioannisian, P. Jetzer, F. R. Joaquim, K-H Kampert, A. Karasu Uysal, T. Katori, N. Kazarian, D. Kerszberg, J. Kowalski-Glikman, S. Kuroyanagi, C. Lammerzahl, J. Levi Said, S. Liberati, E. Lim, I. P. Lobo, M. Lopez-Moya, G. G. Luciano, M. Manganaro, A. Marciano, P. Martin-Moruno, Manel Martinez, Mario Martinez, H. Martinez-Huerta, P. Martinez-Mirave, M. Masip, D. Mattingly, N. Mavromatos, A. Mazumdar, F. Mendez, F. Mercati, S. Micanovic, J. Mielczarek, A. L. Miller, M. Milosevic, D. Minic, L. Miramonti, V. A. Mitsou, P. Moniz, S. Mukherjee, G. Nardini, S. Navas, M. Niechciol, A. B. Nielsen, N. A. Obers, F. Oikonomou, D. Oriti, C. F. Paganini, S. Palomares-Ruiz, R. Pasechnik, V Pasic, C. Perez de los Heros, C. Pfeifer, M. Pieroni, T. Piran, A. Platania, S. Rastgoo, J. J. Relancio, M. A. Reyes, A. Ricciardone, M. Risse, M. D. Rodriguez Frias, G. Rosati, D. Rubiera-Garcia, H. Sahlmann, M. Sakellariadou, F. Salamida, E. N. Saridakis, P. Satunin, M. Schiffer, F. Schussler, G. Sigl, J. Sitarek, J. Sola Peracaula, C. F. Sopuerta, T. P. Sotiriou, M. Spurio, D. Staicova, N. Stergioulas, S. Stoica, J. Striskovic, T. Stuttard, D. Sunar Cerci, Y. Tavakoli, C. A. Ternes, T. Terzic, T. Thiemann, P. Tinyakov, M. D. C. Torri, M. Tortola, C. Trimarelli, T. Trzesniewski, A. Tureanu, F. R. Urban, E. C. Vagenas, D. Vernieri, V. Vitagliano, J-C Wallet, J. D. Zornoza
Summary: The exploration of the universe has entered a new era with the multi-messenger paradigm, providing us with more information about the universe and opening up the possibility of searching for quantum gravity phenomena.
PROGRESS IN PARTICLE AND NUCLEAR PHYSICS
(2022)
Article
Physics, Particles & Fields
Raul Carballo-Rubio, Francesco Di Filippo, Stefano Liberati, Matt Visser
Summary: This paper presents a systematic study of the geometric structure of non-singular spacetimes describing black holes in Lorentz-violating gravity. The concept of trapping horizons and marginally trapped surfaces is reviewed and their significance in frameworks with modified dispersion relations is studied. The notion of universally marginally trapped surfaces is introduced as a generalization for frameworks with infinite signal velocities, leading to the definition of universal trapping horizons. The interplay between the kinematical part of Penrose's singularity theorem and the existence of multiple different metrics is explored, resulting in a complete classification of all possible geometries without incomplete physical trajectories or curvature singularities. The taxonomy of geodesically complete black holes in Horava-like frameworks includes scenarios such as evaporating regular black holes, regular black holes bouncing into regular white holes, and hidden wormholes.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Andrea Maselli, Nicola Franchini, Leonardo Gualtieri, Thomas P. Sotiriou, Susanna Barsanti, Paolo Pani
Summary: This article reports on the Laser Interferometer Space Antenna (LISA)'s capability to detect the presence of a scalar field in extreme mass-ratio inspirals (EMRIs) and measure the scalar charge of the compact object. The results demonstrate that LISA can detect and measure the scalar charge with an unprecedented level of precision, reaching an accuracy of approximately one percent.
Article
Astronomy & Astrophysics
Joshua Baines, Thomas Berry, Alex Simpson, Matt Visser
Summary: The authors have investigated a novel Painleve-Gullstrand variant of the slow-rotation Lense-Thirring spacetime, which has elegant features such as unit lapse, flat spatial 3-slices, and a separable Klein-Gordon equation. They have explored the geodesics in detail and found the occurrence of ultra-elliptic integrals. They also discovered that the complete integrability of the geodesics can only be explicitly expressed in terms of elementary functions in certain special cases. This model has significant implications in astrophysics and can be used to study the asymptotic large-distance limit and compare with astronomical observations as a mimic of a black hole.
Article
Astronomy & Astrophysics
Alex Simpson, Matt Visser
Summary: In this study, a highly tractable non-singular modification of the Kerr geometry, known as the eye of the storm, is analyzed in detail. The physics in this spacetime becomes extraordinarily manageable compared to similar candidates in the literature, making it suitable for straightforward extraction of astrophysical observables falsifiable or verifiable by the experimental community.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Francesco Di Filippo, Raul Carballo-Rubio, Stefano Liberati, Costantino Pacilio, Matt Visser
Summary: This short work reviews the physical mechanism leading to the instability of the central core in regular black holes and argues for the importance of taking into account non-perturbative backreaction for a meaningful description of physical black holes.
Article
Astronomy & Astrophysics
Joshua Baines, Thomas Berry, Alex Simpson, Matt Visser
Summary: In this article, we explore the non-equatorial constant-r geodesics in the Painleve-Gullstrand variant of the Lense-Thirring spacetime. Despite the lack of spherical symmetry, shells of constant-r geodesics still exist in this spacetime. The determination of the allowed locations and the stability analysis of these geodesics is complex. The angular motion of these geodesics exhibits precession and nutation, typically with incommensurate frequencies. This study is important for understanding physical models similar to the Kerr spacetime.
GENERAL RELATIVITY AND GRAVITATION
(2022)
Review
Physics, Particles & Fields
K. G. Arun, Enis Belgacem, Robert Benkel, Laura Bernard, Emanuele Berti, Gianfranco Bertone, Marc Besancon, Diego Blas, Christian G. Bohmer, Richard Brito, Gianluca Calcagni, Alejandro Cardenas-Avendano, Katy Clough, Marco Crisostomi, Valerio De Luca, Daniela Doneva, Stephanie Escoffier, Jose Maria Ezquiaga, Pedro G. Ferreira, Pierre Fleury, Stefano Foffa, Gabriele Franciolini, Noemi Frusciante, Juan Garcia-Bellido, Carlos Herdeiro, Thomas Hertog, Tanja Hinderer, Philippe Jetzer, Lucas Lombriser, Elisa Maggio, Michele Maggiore, Michele Mancarella, Andrea Maselli, Sourabh Nampalliwar, David Nichols, Maria Okounkova, Paolo Pani, Vasileios Paschalidis, Alvise Raccanelli, Lisa Randall, Sebastien Renaux-Petel, Antonio Riotto, Milton Ruiz, Alexander Saffer, Mairi Sakellariadou, Ippocratis D. Saltas, B. S. Sathyaprakash, Lijing Shao, Carlos F. Sopuerta, Thomas P. Sotiriou, Nikolaos Stergioulas, Nicola Tamanini, Filippo Vernizzi, Helvi Witek, Kinwah Wu, Kent Yagi, Stoytcho Yazadjiev, Nicolas Yunes, Miguel Zilhao, Niayesh Afshordi, Marie-Christine Angonin, Vishal Baibhav, Enrico Barausse, Tiago Barreiro, Nicola Bartolo, Nicola Bellomo, Ido Ben-Dayan, Eric A. Bergshoeff, Sebastiano Bernuzzi, Daniele Bertacca, Swetha Bhagwat, Beatrice Bonga, Lior M. Burko, Geoffrey Compere, Giulia Cusin, Antonio da Silva, Saurya Das, Claudia de Rham, Kyriakos Destounis, Ema Dimastrogiovanni, Francisco Duque, Richard Easther, Hontas Farmer, Matteo Fasiello, Stanislav Fisenko, Kwinten Fransen, Jorg Frauendiener, Jonathan Gair, Laszlo Arpad Gergely, Davide Gerosa, Leonardo Gualtieri, Wen-Biao Han, Aurelien Hees, Thomas Helfer, Jorg Hennig, Alexander C. Jenkins, Eric Kajfasz, Nemanja Kaloper, Vladimir Karas, Bradley J. Kavanagh, Sergei A. Klioner, Savvas M. Koushiappas, Macarena Lagos, Christophe Le Poncin-Lafitte, Francisco S. N. Lobo, Charalampos Markakis, Prado Martin-Moruno, C. J. A. P. Martins, Sabino Matarrese, Daniel R. Mayerson, Jose P. Mimoso, Johannes Noller, Nelson J. Nunes, Roberto Oliveri, Giorgio Orlando, George Pappas, Igor Pikovski, Luigi Pilo, Geraint Pratten, Tomislav Prokopec, Hong Qi, Saeed Rastgoo, Angelo Ricciardone, Rocco Rollo, Diego Rubiera-Garcia, Olga Sergijenko, Stuart Shapiro, Deirdre Shoemaker, Alessandro Spallicci, Oleksandr Stashko, Leo C. Stein, Gianmassimo Tasinato, Andrew J. Tolley, Elias C. Vagenas, Stefan Vandoren, Daniele Vernieri, Rodrigo Vicente, Toby Wiseman, Valery Zhdanov, Miguel Zumalacarregui
Summary: This white paper summarizes the importance of LISA in the field of fundamental physics and discusses future research directions and connections with other working groups.
LIVING REVIEWS IN RELATIVITY
(2022)
Article
Physics, Particles & Fields
Matt Visser
Summary: Feynman's i epsilon prescription for quantum field theoretic propagators can be reinterpreted as a complex deformation of the Minkowski spacetime metric. This reinterpretation allows for natural extensions to curved-spacetime QFT and fluctuating spacetime geometries. It also has connections with variants of the weak energy condition.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Joshua Baines, Matt Visser
Summary: Despite decades of research, there is still no widely accepted method to derive the Kerr solution for rotating black holes without significant computational effort. This paper proposes using a non-ortho-normal tetrad and oblate spheroidal coordinates to simplify the angular dependence, separating mass and rotation dependencies in the solution and making it less mysterious.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Astronomy & Astrophysics
Sebastian Schuster, Jessica Santiago, Matt Visser
Summary: This article aims to carefully define the mass of a warp bubble and its movement with respect to fixed stars, as well as examine the concept of mass in warp-drive spacetimes. The study reveals two distinct ways in which mass can appear in connection with warp drive space-time, challenging common assumptions and emphasizing the violation of energy conditions.
GENERAL RELATIVITY AND GRAVITATION
(2023)
Article
Astronomy & Astrophysics
Joshua Baines, Matt Visser
Summary: Thanks to the event horizon telescope, the physical effects of strong-field near-horizon regime for astrophysical black holes can now be tested. The authors discuss a powerful three-function distortion of the Kerr spacetime that can fit observational data and encompass various theoretical models. These spacetimes separate equations and are suitable for modeling real astrophysical black holes. The authors also provide expressions for the horizons' angular velocities, areas, and surface gravities, emphasizing the validity of rigidity results and zeroth laws.
Article
Physics, Particles & Fields
Raul Carballo-Rubio, Francesco Di Filippo, Stefano Liberati, Matt Visser
Summary: We demonstrate the intimate connection between regular black holes and horizonless stars, which are usually considered as distinct families of black hole mimickers. By imposing the non-negativity of gravitational energy and assuming a linear relation between the Misner-Sharp quasi-local mass and the Arnowitt-Deser-Misner (ADM) mass, we show that any spherically symmetric regular black hole can be continuously deformed into a horizonless star. We illustrate this result using Hayward's proposed geometries for regular black holes and describe the properties of the corresponding horizonless stars. The effective stress-energy tensor reveals that these horizonless stars can be identified as anisotropic gravastars with a soft surface and inner/outer light rings. We also present dynamical geometries that could describe the evolution of regular black holes towards horizonless stars, suggesting that semiclassical effects may play a role in the early stages of evolution.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Astronomy & Astrophysics
Joshua Baines, Rudeep Gaur, Matt Visser
Summary: The various defect wormholes discovered by Klinkhamer have gained significant attention lately, particularly the vacuum defect wormhole. However, Feng has proven that the vacuum nature of this wormhole is incorrect, and it is actually an ordinary wormhole with a thin shell of matter. In this article, we examine the fundamental issue causing this discrepancy, which is the discontinuity of the inverse metric at the throat of the wormhole.
Article
Astronomy & Astrophysics
Hector O. Silva, Andrew Coates, Fethi M. Ramazano, Thomas P. Sotiriou
Summary: Spontaneous scalarization allows scalar fields to go undetected in weak gravity and develop nontrivial configurations in strong gravity. However, generalizing this mechanism to vector fields faces a serious obstacle as a ghost appears.
