Why Does the Universe Expand ?
arXiv:1001.3380 · doi:10.1007/s10714-010-1025-1
Abstract
The purpose of the paper is five-fold: (a) Argue that the question in the title can be presented in a meaningful manner and that it requires an answer. (b) Discuss the conventional answers and explain why they are unsatisfactory. (c) Suggest that a key ingredient in the answer could be the instability arising due to the `wrong' sign in the Hilbert action for the kinetic energy term corresponding to expansion factor. (d) Describe how this idea connects up with another peculiar feature of our universe, viz. it spontaneously became more and more classical in the course of evolution. (e) Provide a speculative but plausible scenario, based on the thermodynamic perspective of gravity, in which one has the hope for relating the thermodynamic and cosmological arrows of time.
revtex; 5 pages; no figures
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- Friedmann Equations from Entropic Force
- Surface Density of Spacetime Degrees of Freedom from Equipartition Law in theories of Gravity
- Quantum UV/IR Relations and Holographic Dark Energy from Entropic Force
- Lessons from Classical Gravity about the Quantum Structure of Spacetime
- Entropic force and entanglement system
- Equipartition of energy and the first law of thermodynamics at the apparent horizon
- Limit on graviton mass from galaxy cluster Abell 1689
- Cosmological Constant from the Emergent Gravity Perspective
- Constraining Entropic Cosmology
- Model Comparison tests of modified gravity from the Eöt-Wash experiment
- Do We Really Understand the Cosmos?
- Hidden symmetries for thermodynamics and emergence of relativity
- Entropic force and its cosmological implications
- Towards a Holographic Description of Inflation and Generation of Fluctuations from Thermodynamics
- Entropic force in the presence of black hole
- Does entropic force always imply the Newtonian force law?
- Schwarzschild-de Sitter black hole from entropic viewpoint
- An entropy-driven cosmic expansion