# The Cosmological Constant Problems

@inproceedings{Weinberg2000TheCC, title={The Cosmological Constant Problems}, author={Steven Weinberg}, year={2000} }

The old cosmological constant problem is to understand why the vacuum energy is so small; the new problem is to understand why it is comparable to the present mass density. Several approaches to these problems are reviewed. Quintessence does not help with either; anthropic considerations offer a possibility of solving both. In theories with a scalar field that takes random initial values, the anthropic principle may apply to the cosmological constant, but probably to nothing else.

## 209 Citations

Anthropic Approach to the Cosmological Constant Problems

- Physics
- 2003

There are now two cosmological constant problems: (i) why the vacuum energy is so small and (ii) why it comes to dominate at about the epoch of galaxy formation. Anthropic selection appears to be the…

Cosmological constant problems and their solutions

- Physics
- 2001

There are now two cosmological constant problems: (i) why the vacuum energy is so small and (ii) why it comes to dominate at about the epoch of galaxy formation. Anthropic selection appears to be the…

X-Particle as a Solution for the Cosmological Constant Problem

- Physics
- 2016

The cosmological constant is a fundamental problem in modern physics, and arises at the intersection between general relativity and quantum field theory. In this paper we show how the cosmological…

The cosmological constant puzzle

- Physics
- 2011

The accelerating expansion of the Universe points to a small positive vacuum energy density and negative vacuum pressure. A strong candidate is the cosmological constant in Einstein's equations of…

Is the Zero-Point Energy Real?

- Physics, Philosophy
- 2002

I consider the arguments to show that the vacuum energy density should receive a large contribution from the zero-point energy. This is the cosmological constant problem, as it was originally framed.…

The Cosmological Constant Problem, an Inspiration for New Physics

- Physics
- 2006

We have critically compared different approaches to the cosmological constant problem, which is at the edge of elementary particle physics and cosmology. This problem is deeply connected with the…

BRANE UNIVERSES AND THE COSMOLOGICAL CONSTANT

- Physics, Philosophy
- 2005

The cosmological constant problem and brane universes are reviewed briefly. We discuss how the cosmological constant problem manifests itself in various scenarios for brane universes. We review…

The Solution of the Cosmological Constant Problem: The Cosmological Constant Exponential Decrease in the Super-Early Universe

- Physics
- 2020

The stage of a super-early (primordial) scale-invariant Universe is considered on the basis of the Poincare–Weyl gauge theory of gravity in a Cartan–Weyl space-time. An approximate solution has been…

Installing of cosmological constant

- Physics
- 2013

An artificial scale of observable cosmological constant is dynamically related to its natural bare value due to an installation of relevant coherent state for the inflationary field in a finite…

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