In this paper, we investigate the quasinormal modes (QNMs) of a Lorentz-violating spacetime, factoring in a cosmological constant, within the framework of Einstein-Bumblebee gravity. Our findings reveal that the interaction of spacetime with an anisotropic bumblebee field imparts distinct contributions to the axial and polar sectors of the vector perturbations. This subsequently breaks the isospectrality typically observed in vector modes. Numerical evidence strongly indicates isospectral breaking in the vector modes of Einstein-Bumblebee black holes: a pronounced breakage in the real part of the frequencies, while the imaginary component seems less affected. This isospectral breaking indicates the existence of two different waveforms in the Ringdown phase of the black hole, which provides a potential signal of quantum gravity observable in current experiments.
The vacuum solutions arising from a spontaneous breaking of Lorentz symmetry due to the acquisition of a vacuum expectation value by a vector field are derived. These include the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB scenarios. It is found that the purely radial LSB case gives rise to new black hole solutions. Whenever possible, Parametrized Post-Newtonian (PPN) parameters are computed and compared to observational bounds, in order to constrain the Lorentz symmetry breaking scale.
Constrain from shadows of $M87^*$ and $Sgr A^*$ and quasiperiodic oscillations of galactic microquasars on a black hole arising from metric-affine bumblebee model
Optical and Thermodynamic Signatures of Lorentz Symmetry Breaking in Bumblebee AdS Black Holes
University of Mazandaran（马赞德兰大学）；Khazar University（哈扎尔大学）；Erzurum Technical University（埃尔祖鲁姆理工大学）；Hakkari University（哈卡里大学）；Eastern Mediterranean University（东地中海大学）
Thermodynamics and Optical Properties of Charged Black Holes in Bumblebee gravity Sourced by a Cloud of Strings
The Assam Royal Global University（阿萨姆皇家全球大学）；The Institute of Mathematical Sciences, C. I. T. Campus（马哈拉施特拉理工学院数学科学研究所）；Al-Hussein Bin Talal University（侯赛因·本·塔拉勒大学）
We have studied the quasinormal modes (QNMs) of a slowly rotating black hole with Lorentz-violating parameter in Einstein-bumblebee gravity. We analyse the slow rotation approximation of the rotating black hole in the Einstein-bumblebee gravity, and obtain the master equations for scalar perturbation, vector perturbation and axial gravitational perturbation, respectively. Using the matrix method and the continuous fraction method, we numerically calculate the QNM frequencies. In particular, for scalar field, it shows that the QNMs up to the second order of rotation parameter have higher accura…
Bumblebee gravity is one of the simplest gravity theories with spontaneous Lorentz symmetry breaking. Since we know a rotating black hole solution in bumblebee gravity, we can potentially test this model with the available astrophysical observations of black holes. In this work, we construct a reflection model in bumblebee gravity and we use our model to analyze the reflection features of a NuSTAR spectrum of the Galactic black hole EXO 1846-031 in order to constrain the Lorentz-violating parameter $\ell$. We find that the analysis of the reflection features in the spectrum of EXO 1846-031 can…
A metric with a Lorentz violating parameter is associated with the bumblebee gravity model. We study the motion of a particle in this bumblebee background where the dynamical variables satisfy non-canonical Snyder algebra along with some critical survey on the classical observations in the bumblebee background to see how these would likely differ from Schwarzschild background. It has been found that the perihelion shift acquires a generalized expression with two independent parameters. One of these two is connected with the Lorentz violating factor and the other is involved in the Snyder algeb…
Constraining Lorentz symmetry breaking in bumblebee gravity with extreme mass-ratio inspirals
Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences（中国科学院大学杭州高等研究院）；Hunan Normal University（湖南师范大学）；Beijing Normal University（北京师范大学）；Yangzhou University（扬州大学）
When Bumblebee Meets NLED: Lorentz-Violating Black Holes and Regular Spacetimes
Center for Joint Quantum Studies, Department of Physics, School of Science, Tianjin University（天津大学理学院物理系联合量子研究中心）；The International Joint Institute of Tianjin University, Fuzhou, Tianjin University（天津大学福州国际联合学院）
The bumblebee field coupled with gravity is considered. This gravitational theory exhibits spontaneous breaking of Lorentz symmetry. The Gödel-type universe is introduced and then the causality and its violation are studied. Causal and non-causal Gödel-type solutions are obtained for different content of matter. In addition, when the coupling constant, which controls the interaction between the bumblebee field and the gravitational field, is zero the bumblebee potential may be associated with the value of the cosmological constant of the general relativity. Furthermore, the case with the non-z…
The Bumblebee Model of spontaneous Lorentz symmetry breaking is explored in a cosmological context, considering a single non-zero time component for the vector field. The relevant dynamic equations for the evolution of the Universe are derived and its properties and physical significance studied. We conclude that a late-time de Sitter expansion of the Universe can be replicated, and attempt to constrain the parameter of the potential driving the spontaneous symmetry breaking.
This work investigates the influence of the Lorentz symmetry breaking in the bending angle of massive particles and light for bumblebee black hole solutions. The solutions analyzed break the Lorentz symmetry due to a non-zero vacuum expectation value of the bumblebee field. We use the Ishihara method, which allows us to study the bending angle of light for finite distances, and it is applicable to non-asymptotically flat spacetimes when considering the receiver viewpoint. In order to analyze the deflection of massive particles, we systematize the Ishihara method for its application in the Jaco…
In this work, we calculate the quasi-normal frequencies from a bumblebee traversable wormhole. The bumblebee wormhole model is based on the bumblebee gravity, which exhibits a spontaneous Lorentz symmetry breaking. Supporting by the Lorentz violation parameter $λ$, this model allows the fulfillment of the flare-out and energy conditions, granted non-exotic matter to the wormhole. We analyze the parameters of bumblebee wormhole in order to obtain a Reege-Wheeler's equation with a bell-shaped potential. We obtain the quasi-normal modes (QNMs) via the WKB approximation method for both scalar and …
Gravitational Wave Standard Sirens as Probes of Lorentz Violation in Bumblebee Gravity
University of KwaZulu–Natal（夸祖鲁-纳塔尔大学）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；Central Asian University（中亚大学）；Ulugh Beg Astronomical Institute（乌鲁伯格天文学研究所）；Universidad de La Frontera（拉弗龙特拉大学）；Kimyo International University in Tashkent（塔什干化学国际大学）；Alfraganus University（阿尔法拉甘努斯大学）
In the Einstein-bumblebee gravity, the Lorentz symmetry is spontaneously broken by a vector field. In this paper, we attempt to test the Lorentz symmetry via the observation of the shadow cast by the Kerr-like black hole with or without plasma. A novel phenomenon of the Lorentz-violating parameter on the shadow is observed. The result shows that when the observer gradually moves from the poles to the equatorial plane, the shadow radius $R_{\rm s}$ firstly decreases and then increases with the Lorentz-violating parameter. Such nonmonotonic behavior provides us an important understanding on the …
We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding $rr$ and $tϕ$ components of the gravitational field equations in both cases: A, $b_μ=(0,b(r),0,0)$; B, $b_μ=(0,b(r),\mathfrak{b}(θ),0)$. Then we check the other gravitational field equations and the bumblebee field motion equations by using this solution. We find that in the case A, there exists a slowly rotating black hole solution indeed for arbitrary LV (Lorentz violation) coupling constant $\ell$; however as in the case B, there exists this slowly rotating solution if and only if the coup…
Tidal Deformability of Neutron Stars in Bumblebee Gravity: Probing Lorentz Symmetry Breaking with Gravitational Waves
Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal（夸祖鲁-纳塔尔大学）；Samarkand State University（撒马尔罕国立大学）；Tashkent State Technical University（塔什干国立技术大学）；Institute of Theoretical Physics, National University of Uzbekistan（乌兹别克斯坦国立大学理论物理研究所）；School of Physics, Harbin Institute of Technology（哈尔滨工业大学）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；Kimyo International University in Tashkent（塔什干基姆约国际大学）；Hourani Center for Applied Scientific Research, Al-Ahliyya Amman University（安曼阿赫利耶大学）；Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences（萨维塔医学与技术科学研究所）
Primordial black hole in Lorentz-violating theories: Insights from Bumblebee gravity
Institute for Research in Fundamental Sciences (IPM)（基础科学研究所）；Damghan University（达姆甘大学）；Khazar University（哈萨尔大学）；K. N. Toosi University of Technology（科·恩·托伊西理工大学）
We have obtained the Generalized Uncertainty Principle (GUP) corrected de Sitter and anti-de Sitter black hole solutions in bumblebee gravity with a topological defect. We have calculated the scalar, electromagnetic and gravitational quasinormal modes for the both vanishing and non-vanishing effective cosmological constant using Padé averaged sixth order WKB approximation method. Apart from this, the time evolutions for all three perturbations are studied, and quasinormal modes are calculated using the time domain profile. We found that the first order and second order GUP parameters $α$ and $…
A Kerr-Sen-like black hole solution appears in the Einstein-bumblebee theory of gravity. The solution contains contains a Lorentz violating parameter in an explicit manner. We study the null geodesics in the background of this Kerr-Sen-like black hole surrounded by a dispersive medium like plasma. We investigate the effect of the charge of the black hole, the Lorentz violation parameter, and the plasma parameter on the photon orbits with the evaluation of the effective potential in the presence of both the Lorentz violation parameter and the plasma parameter. We also study the influence of the…
We have studied quasi-periodic oscillations frequencies in a rotating black hole with Lorentz symmetry breaking parameter in Einstein-bumblebee gravity by relativistic precession model. We find that in the rotating case with non-zero spin parameter both of the periastron and nodal precession frequencies increase with the Lorentz symmetry breaking parameter, but the azimuthal frequency decreases. In the non-rotating black hole case, the nodal precession frequency disappears for arbitrary Lorentz symmetry breaking parameter. With the observation data of GRO J1655-40, XTE J1550-564, and GRS 1915+…
Lorentz violation modifies the dispersion relation of gravitational waves (GWs), and induces birefringence and anisotropy in propagation. Our study shows that Lorentz violation can also activate multiple polarizations of GWs. We use the gauge invariants to investigate the polarizations of GWs in the bumblebee gravity model, and obtain the following results. (i) For a vector background $b^μ$ with only a nonzero temporal component $b^t$, there are five independent propagating degrees of freedom (DOFs), which is simlar to the Einstein-aether theory. (ii) The presence of a spatial component in the…
In this study, we found a new traversable wormhole solution in the framework of a bumblebee gravity model. With these types of models, the Lorentz symmetry violation arises from the dynamics of a bumblebee vector field that is non-minimally coupled with gravity. To this end, we checked the wormhole's flare-out and energy (null, weak, and strong) conditions. We then studied the deflection angle of light in the weak limit approximation using the Gibbons-Werner method. In particular, we show that the bumblebee gravity effect leads to a non-trivial global topology of the wormhole spacetime. By usi…
We study the accretion process in the thin disk around a rotating Kerr-like black hole in Einstein-bumblebee gravity model where Lorentz symmetry is spontaneously broken once a vector field acquires a vacuum expectation value. In the present paper we obtain the energy flux, the emission spectrum and accretion efficiency from the accretion disks around the rotating Kerr-like black hole, and we compare them to the general Kerr case. These significant features in the mass accretion process may provide a possibility to test whether the Lorentz symmetry is spontaneously broken or not in the Einstei…
Symmetric teleparallel gravity (STG) is an alternative description of the gravitational field as an effect of the nonmetricity rather than the curvature of the spacetime. For an specific choice of the symmetric teleparallel lagrangian, the STG dynamics is equivalent to the general relativity (GR), and it is called Symmetric teleparallel equivalent to general relativity (STEGR). We propose a local Lorentz violating dynamics in the gravitational sector in the STEGR framework. The Lorentz violation is trigged by the vacuum expectation value (vev) of the well-known bumblebee field, whose vev coupl…
We present firstly the equation of motion for the photon coupled to a special bumblebee vector field in a Kerr black hole spacetime and find that the propagation of light depends on its polarization due to the birefringence phenomenon. The dependence of black hole shadow on the light's polarization is dominated by the rotation of black hole. In the non-rotating case, we find that the black hole shadow is independent of the polarization of light. However, the status is changed in the rotating case, in which the black hole shadow depends on the light's polarization and the coupling between bumbl…
We have obtained an exact vacuum solution from a gravity sector contained in the minimal standard-model extension. The theoretical model assumes a Riemann spacetime coupled to the bumblebee field which is responsible for the spontaneous Lorentz symmetry breaking. The solution achieved in a static and spherically symmetric scenario establishes a Schwarzschild-like black hole. In order to study the effects of the spontaneous Lorentz symmetry breaking, we have investigated some classics tests including the advance of the perihelion, bending of light and Shapiro's time-delay. Furthermore, we have …
Lorentz-Violating (LV) scenario gets involved through a bumblebee field vector field $B_μ$. A spontaneous symmetry breaking allows the field to acquires a vacuum expectation value that generates LV into the system. A Kerr-Sen-like solution has been found out starting from the generalized form of a radiating stationery axially symmetric black-hole metric. We compute the effective potential offered by the null geodesics in the bumblebee rotating black-hole spacetime. The shadow has been sketched for different variations of the parameters involved in the system. A careful investigation has been c…
