[Paper Review] Some Additional Bounds on the Photon Charge

C. Sivaram, Kenath Arun|ArXiv.org|Feb 12, 2008

Dark Matter and Cosmic Phenomena1 references3 citations

TL;DR

This paper establishes stringent upper bounds on the hypothetical electric charge of the photon using multiple astrophysical and cosmological constraints, including dark energy dominance, big bang nucleosynthesis, synchrotron and inverse Compton radiation, and black hole physics. The derived limits are consistent with existing theoretical expectations and reinforce the standard model's prediction of a neutral photon.

ABSTRACT

We have arrived at tight constraints on the photon charge, giving comparable bounds, one based on the dominance by dark energy at the present epoch, and the other based on the requirement that early universe nucleosynthesis not be affected by any residual electrostatic energy due to any miniscule charge on the radiation photons in that era. Limits have also been arrived at from synchrotron and IC effects. We have also set limits on the charge based on the properties of black holes. The set of constraints arrived at in this paper are consistent with those predicted by other authors.

Motivation & Objective

• To constrain the hypothetical electric charge of the photon using multiple astrophysical and cosmological observations.
• To ensure that any residual photon charge does not disrupt early universe nucleosynthesis or alter the dynamics of dark energy dominance.
• To evaluate the impact of photon charge on synchrotron and inverse Compton radiation processes in high-energy astrophysical environments.
• To derive bounds using black hole properties, particularly considering electromagnetic self-energy contributions.
• To provide a consistent set of constraints that align with existing theoretical and observational limits.

Proposed method

• Utilized the dominance of dark energy in the current cosmic epoch to constrain deviations from charge neutrality in photons.
• Applied constraints from big bang nucleosynthesis, requiring that residual electrostatic energy from a charged photon not alter light element abundances.
• Evaluated energy losses via synchrotron radiation and inverse Compton scattering in the presence of a non-zero photon charge.
• Analyzed the electromagnetic self-energy contribution in the context of black hole solutions to derive bounds on photon charge.
• Combined multiple independent physical frameworks into a unified set of upper limits on the photon charge.
• Used a combination of analytical derivations and physical reasoning to derive bounds, expressed through 13 equations in the paper.

Experimental results

Research questions

• RQ1 What upper bound on the photon charge is implied by the current dominance of dark energy in the universe?
• RQ2 How does a non-zero photon charge affect the predicted abundances of light elements during big bang nucleosynthesis?
• RQ3 To what extent do synchrotron and inverse Compton radiation processes place constraints on the photon charge?
• RQ4 How do black hole solutions with electromagnetic self-energy contribute to bounds on the photon charge?
• RQ5 Are the derived bounds on the photon charge consistent with those obtained by other theoretical and observational approaches?

Key findings

• The paper derives a stringent upper bound on the photon charge based on the requirement that it not disrupt the observed abundances of light elements from big bang nucleosynthesis.
• Constraints from dark energy dominance in the present epoch further tighten the upper limit on the photon charge.
• Synchrotron and inverse Compton radiation processes impose additional, non-trivial bounds on the photon charge, especially in high-energy astrophysical environments.
• Black hole solutions involving electromagnetic self-energy provide a complementary and consistent bound on the photon charge.
• The set of derived bounds is mutually consistent and aligns with previously reported limits from other theoretical and observational studies.
• The final bounds are of the order of 10^-42 to 10^-43 e, depending on the specific physical scenario considered, reinforcing the standard model prediction of a neutral photon.