[Paper Review] Does Light Gravitate? (Proposal on New Test of Equivalence Principle)

Anatoli Vankov|arXiv (Cornell University)|Dec 3, 2000

Relativity and Gravitational Theory4 references3 citations

TL;DR

This paper proposes a new test of the Equivalence Principle by analyzing how light's energy and effective mass behave in a gravitational field. Using relativistic mass-energy equivalence, it argues that freely falling particles experience varying proper mass, implying non-equivalent inertial frames; a modified Pound-Rebka experiment in a freely falling lab could detect this violation of the Equivalence Principle.

ABSTRACT

On the basis of the relativistic mass-energy concept we found that a proper mass of a test particle in a gravitational field depends on a potential energy, hence, a freely falling particle has a varying proper mass. Consequently, a multitude of freely falling reference frames cannot be regarded as the multitude of equivalent inertial reference frames. There is a class of experiments, which allow distinguishing between them. If so, a demonstration of a violation of the Equivalence Principle is possible. It is shown that a variant of the classical Pound-Rebka-Snider experiment on a photon frequency shift in a gravitational field if conducted in a freely falling laboratory would be such a test.

Motivation & Objective

• To investigate whether light gravitates by examining the implications of relativistic mass-energy equivalence in gravitational fields.
• To challenge the standard assumption that all freely falling reference frames are equivalent inertial frames.
• To identify experimental conditions under which the Equivalence Principle might be violated.
• To propose a modified version of the Pound-Rebka-Snider experiment as a testable scenario for detecting such violations.
• To explore the dependence of proper mass on gravitational potential energy in relativistic mechanics.

Proposed method

• Applies the relativistic mass-energy equivalence principle to derive the proper mass of a test particle in a gravitational potential.
• Analyzes the variation of proper mass for a freely falling particle due to changes in potential energy.
• Considers the implications of variable proper mass for the equivalence of inertial and gravitational reference frames.
• Proposes a modified Pound-Rebka experiment conducted in a freely falling laboratory frame to detect frequency shifts attributable to mass variation.
• Uses the framework of general relativity and the equivalence principle to assess the consistency of the proposed test.
• Evaluates the feasibility of distinguishing between inertial frames based on the time-dependent proper mass of particles.

Experimental results

Research questions

• RQ1 Can the proper mass of a freely falling particle vary due to changes in gravitational potential energy?
• RQ2 Does the variation of proper mass in a gravitational field imply a breakdown of the equivalence between inertial and gravitational reference frames?
• RQ3 Can a modified Pound-Rebka experiment in a freely falling lab detect deviations from the Equivalence Principle?
• RQ4 Is there a physical distinction between freely falling reference frames if proper mass is not constant?
• RQ5 What are the observable consequences of treating light as having a variable effective mass in a gravitational field?

Key findings

• The proper mass of a freely falling particle varies with gravitational potential energy, implying that its inertial mass is not constant.
• This variation invalidates the assumption that all freely falling frames are equivalent inertial frames, challenging a foundational postulate of general relativity.
• A modified Pound-Rebka experiment conducted in a freely falling laboratory could detect frequency shifts due to the changing proper mass of photons.
• The proposed test provides a potential experimental signature for a violation of the Equivalence Principle.
• The analysis suggests that light, due to its energy and relativistic mass, may gravitate in a way inconsistent with standard interpretations of the Equivalence Principle.
• The results imply that the Equivalence Principle may not hold universally if proper mass depends on potential energy in a dynamic gravitational field.