New test on the Einstein equivalence principle through the photon ring of black holes

Abstract

Einstein equivalence principle (EEP), as one of the foundations of general relativity, is a fundamental test of gravity theories. In this paper, we propose a new method to test the EEP of electromagnetic interactions through observations of black hole photon rings, which naturally extends the scale of Newtonian and post-Newtoian gravity where the EEP violation through a variable fine structure constant has been well constrained to that of stronger gravity. We start from a general form of Lagrangian that violates EEP, where a specific EEP violation model could be regarded as one of the cases of this Lagrangian. Within the geometrical optical approximation, we find that the dispersion relation of photons is modified: for photons moving in circular orbit, the dispersion relation simplifies, and behaves such that photons with different linear polarizations perceive different gravitational potentials. This makes the size of black hole photon ring depend on polarization. Further assuming that the EEP violation is small, we derive an approximate analytic expression for spherical black holes showing that the change in size of the photon ring is proportional to the violation parameters. We also discuss several cases of this analytic expression for specific models. Finally, we explore the effects of black hole rotation and derive a modified proportionality relation between the change in size of photon ring and the violation parameters. The numerical and analytic results show that the influence of black hole rotation on the constraints of EEP violation is relatively weak for small magnitude of EEP violation and small rotation speed of black holes.

arXiv comment16 pages, 6 figures

References in corpus (84)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Modified Gravity and Cosmology
• The Confrontation between General Relativity and Experiment
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Black Hole Shadows, Photon Rings, and Lensing Rings
• The geometry of photon surfaces
• Discovering the QCD Axion with Black Holes and Gravitational Waves
• Rotating regular black holes
• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• Testing the No-Hair Theorem with Observations in the Electromagnetic Spectrum: II. Black-Hole Images
• Shadow of rotating regular black holes
• Universal Interferometric Signatures of a Black Hole's Photon Ring
• Hunting for extra dimensions in the shadow of M87*
• Shadow of a black hole surrounded by dark matter
• Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
• Matter-gravity couplings and Lorentz violation
• A Simple Varying-alpha Cosmology
• Black holes with scalar hair in light of the Event Horizon Telescope
• The innermost stable circular orbit and shadow in the novel $4D$ Einstein-Gauss-Bonnet gravity
• Gravitational deflection of light and shadow cast by rotating Kalb-Ramond black holes
• The Shadow of a Spherically Accreting Black Hole
• The Shape of the Black Hole Photon Ring: A Precise Test of Strong-Field General Relativity
• Equivalence Principle Implications of Modified Gravity Models
• Ultra Light Boson Dark Matter and Event Horizon Telescope Observations of M87*
• Silhouette of M87*: A new window to peek into the world of hidden dimensions
• Black Hole Surrounded by a Dark Matter Halo in the M87 Galactic Center and its Identification with Shadow Images
• The Spectra of Gravitational Atoms
• Shadows of Kerr black holes with and without scalar hair
• Shadows and deflection angle of charged and slowly rotating black holes in Einstein-Æther theory
• Photon Ring and Observational Appearance of a Hairy Black Hole
• Equivalence Principle and Gravitational Redshift
• Universal Polarimetric Signatures of the Black Hole Photon Ring
• Probing Axions with Event Horizon Telescope Polarimetric Measurements
• EHT constraint on the ultralight scalar hair of the M87 supermassive black hole
• Asymptotic safety casts its shadow
• Can the EHT M87 results be used to test general relativity?
• Shadows of Sgr A${}^{\ast }$ Black Hole Surrounded by Superfluid Dark Matter Halo
• GRay: a Massively Parallel GPU-Based Code for Ray Tracing in Relativistic Spacetimes
• Nonequivalence of equivalence principles
• Precision Gravity Tests and the Einstein Equivalence Principle
• Einstein-Æther Gravity in the light of Event Horizon Telescope Observations of M87*
• Charged black holes in nonlinear massive gravity
• Probing Quintessence with Time Variation of Couplings
• Looking for ultralight dark matter near supermassive black holes
• Black holes in an asymptotically safe gravity theory with higher derivatives
• Photon Ring Autocorrelations
• Gravity's Rainbow: Limits for the applicability of the equivalence principle
• Shadow cast of non-commutative black holes in Rastall gravity
• On the Observable Shape of Black Hole Photon Rings
• Shadow and deflection angle of rotating black hole in asymptotically safe gravity
• `Faster than light' photons and rotating black holes
• Evolution of black hole shadow in the presence of ultralight bosons
• Search for a Variation of the Fine Structure around the Supermassive Black Hole in Our Galactic Center
• Propagation of vacuum polarized photons in topological black hole spacetimes
• Testing the equivalence principle via the shadow of black holes
• Polarization effects in Kerr black hole shadow due to the coupling between photon and bumblebee field
• Shadow of a rotating squashed Kaluza-Klein black hole
• Double shadow of a regular phantom black hole as photons couple to Weyl tensor
• Testing the Schwarzschild metric in a strong field region with the Event Horizon Telescope
• Test of Einstein equivalence principle near the Galactic center supermassive black hole
• Studying Black Holes on Horizon Scales with VLBI Ground Arrays
• Rotating dirty black hole and its shadow
• Scattering of circularly polarized light by a rotating black hole
• Measuring the shape of a black hole photon ring
• The Shapiro time delay and the equivalence principle
• Maxwell equations in a curved spacetime: Spin optics approximation
• Features and stability analysis of non-Schwarzschild black hole in quadratic gravity
• Galactic-center S-Stars as a prospective test of the Einstein Equivalence Principle
• Superradiant stability of the Kerr black holes
• Implications of axionic hair on shadow of M87*
• Equivalence Principle in Chameleon Models
• Gravitational Atoms
• Geometric optics in the presence of axion-like particles in curved space-time
• Cosmic Transients, Einstein's Equivalence Principle and Dark Matter Halos
• Testing the Equivalence Principle with Strong Lensing Time Delay Variations
• The Timescale for Loss of Massive Vector Hair by a Black Hole and its Consequences for Proton Decay
• Shadows of rotating black holes in alternative theories
• Post-Newtonian phenomenology of a massless dilaton
• Charge conservation and Equivalence principle
• Studying black holes on horizon scales with space-VLBI

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