1999arXiv (Cornell University)Open access

Cosmic acceleration and a natural solution to the cosmological constant problem

Philip D. Mannheim

Open full text 0 citations

Abstract

We trace the origin of the cosmological constant problem to the assumption that Newton's constant $G$ sets the scale for cosmology. And then we show that once this assumption is relaxed, the very same cosmic acceleration which has served to make the cosmological constant problem so very severe instead then serves to provide us with its potential resolution. We present an alternate cosmology, one based on conformal gravity, and show that once given only that the sign of the vacuum energy density $Λ$ is explicitly the negative one associated with spontaneous breakdown of the scale invariance of the conformal theory (this actually being the choice of sign for $Λ$ which precisely leads to cosmic acceleration in conformal gravity), then that alone, no matter how big $Λ$ might actually be in magnitude, is sufficient to not only make its measurable contribution to current era cosmology naturally be of order one today, but to even do so in a way which is completely compatible with the recent high $z$ supernovae cosmology data. Cosmology can thus live with either a fundamental $G$ or with the large (and even potentially negative) $Λ$ associated with elementary particle physics phase transitions but not with both. Also, we distinguish between the free energy and the internal energy, with it being the former which determines cosmological phase transitions and the latter which is the source of the gravitational field. Then we show that, even if we make the standard ad hoc assumption that $Λ$ actually is quenched in standard gravity, vacuum energy is nonetheless still found to dominate standard cosmology at the time of the phase transition which produced it. However, within conformal gravity no such difficulty is encountered.

Open-access reader

About this research paper

What this paper is about

We trace the origin of the cosmological constant problem to the assumption that Newton's constant $G$ sets the scale for cosmology. And then we show that once this assumption is relaxed, the very same cosmic acceleration which has served to make the cosmological constant problem so very severe instead then serves to provide us with its potential resolution. We present an alternate cosmology, one based on conformal gravity, and show that once given only that the sign of the vacuum energy density $Λ$ is explicitly the negative one associated with spontaneous breakdown of the scale invariance of the conformal theory (this actually being the choice of sign for $Λ$ which precisely leads to cosmic acceleration in conformal gravity), then that alone, no matter how big $Λ$ might actually be in magnitude, is sufficient to not only make its measurable contribution to current era cosmology naturally be of order one today, but to even do so in a way which is completely compatible with the recent high $z$ supernovae cosmology data. Cosmology can thus live with either a fundamental $G$ or with the large (and even potentially negative) $Λ$ associated with elementary particle physics phase transitions but not with both. Also, we distinguish between the free energy and the internal energy, with it being the former which determines cosmological phase transitions and the latter which is the source of the gravitational field. Then we show that, even if we make the standard ad hoc assumption that $Λ$ actually is quenched in standard gravity, vacuum energy is nonetheless still found to dominate standard cosmology at the time of the phase transition which produced it. However, within conformal gravity no such difficulty is encountered.

Why it matters

A significance statement is not available in the OpenAlex record.

Key contribution

A contribution statement is not available in the OpenAlex record.

Method / approach

Method details are not available in the OpenAlex metadata.

Main findings

Findings are not separately available in the OpenAlex metadata.

Limitations

Limitations are not available in the OpenAlex metadata.

Applications

Application details are not available in the OpenAlex metadata.

Available abstract

We trace the origin of the cosmological constant problem to the assumption that Newton's constant $G$ sets the scale for cosmology. And then we show that once this assumption is relaxed, the very same cosmic acceleration which has served to make the cosmological constant problem so very severe instead then serves to provide us with its potential resolution. We present an alternate cosmology, one based on conformal gravity, and show that once given only that the sign of the vacuum energy density $Λ$ is explicitly the negative one associated with spontaneous breakdown of the scale invariance of the conformal theory (this actually being the choice of sign for $Λ$ which precisely leads to cosmic acceleration in conformal gravity), then that alone, no matter how big $Λ$ might actually be in magnitude, is sufficient to not only make its measurable contribution to current era cosmology naturally be of order one today, but to even do so in a way which is completely compatible with the recent high $z$ supernovae cosmology data. Cosmology can thus live with either a fundamental $G$ or with the large (and even potentially negative) $Λ$ associated with elementary particle physics phase transitions but not with both. Also, we distinguish between the free energy and the internal energy, with it being the former which determines cosmological phase transitions and the latter which is the source of the gravitational field. Then we show that, even if we make the standard ad hoc assumption that $Λ$ actually is quenched in standard gravity, vacuum energy is nonetheless still found to dominate standard cosmology at the time of the phase transition which produced it. However, within conformal gravity no such difficulty is encountered.

Key concepts: Physics, Cosmological constant, Cosmology, Cosmological constant problem, Conformal gravity, Theoretical physics, Physical cosmology, Dark energy

Related papers

Back to paper searchBrowse research topicsOriginal source
Cosmic acceleration and a natural solution to the cosmological constant problem — Research Paper | ScholarLens