Conformal invariance, microscopic physics, and the nature of gravitation

Journal Article · Mon Sep 15 04:00:00 EDT 1980 · Phys. Rev., D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.22.1313· OSTI ID:5124081

Bekenstein, J D; Meisels, A

Variation of the gravitational ''constant'' in spacetime is discussed. The issue may be fully resolved if one accepts the principle that all the fundamental equations of physics should be invariant under local (spacetime-dependent) transformations of units (principle of conformal invariance). Theoretical arguments in favor of the principle are discussed. The presently accepted dynamics for the fundamental particles satisfy the principle. Their conformal invariance is due not least to the indispensable transformation properties of rest masses. Thus in arbitrary units each type of rest mass is a spacetime field. The principle of conformal invariance then demands conformal invariance of the dynamics of each such ''mass field.'' If all rest-mass ratios are strictly constant, there is only one mass field. Its dynamics automatically induces dynamics for gravitation. In units defined by particle masses the gravitational action is manifestly that of general relativity. This fact would seem to forbid the construction of a conformally invariant theory of gravitation with ''varying gravitational constant'' G. Gravitational (Einstein) units have been argued to be distinct from those defined by matter (atomic units). To implement such distinction while simultaneously avoiding undetermined elements in the theory, one must introduce conformally invariant dynamics for gravitation and for the mass field separately. This theory, a ''varying-G theory.'' is definitely ruled out by the solar-system gravitational experiments. We conclude that the principle of conformal invariance requires that gravitation be described by general relativity, and that the dimensionless gravitational constant ..gamma.. be strictly constant. We also consider the possibility that gravitation, or the mass field, explicitly break conformal invariance. For most cosmological models, the temporal variability of ..gamma.. is well below experimental sensitivities.

• Research Organization: Institute for Theoretical Physics, University of California, Santa Barbara, California 93106
• OSTI ID: 5124081
• Journal Information: Phys. Rev., D; (United States), Journal Name: Phys. Rev., D; (United States) Vol. 22:6; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

640106* -- Astrophysics & Cosmology-- Cosmology
657003 -- Theoretical & Mathematical Physics-- Relativity & Gravitation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CONFORMAL INVARIANCE
COSMOLOGICAL MODELS
FUNDAMENTAL CONSTANTS
GAUGE INVARIANCE
GRAVITATION
INTERACTIONS
INVARIANCE PRINCIPLES
MASS
MATHEMATICAL MODELS
METRICS
PARTICLE INTERACTIONS
REST MASS
SPACE-TIME
TIME DEPENDENCE