Separating dark physics from physical darkness: Minimalist modified gravity versus dark energy
- Kavli Institute for Cosmological Physics and Astronomy and Astrophysics Department, University of Chicago, Chicago, Illinois 60637 (United States)
- Berkeley Lab, University of California, Berkeley, California 94720 (United States)
The acceleration of the cosmic expansion may be due to a new component of physical energy density or a modification of physics itself. Mapping the expansion of cosmic scales and the growth of large scale structure in tandem can provide insights to distinguish between the two origins. Using Minimal Modified Gravity (MMG) - a single parameter gravitational growth index formalism to parametrize modified gravity theories - we examine the constraints that cosmological data can place on the nature of the new physics. For next generation measurements combining weak lensing, supernovae distances, and the cosmic microwave background we can extend the reach of physics to allow for fitting gravity simultaneously with the expansion equation of state, diluting the equation of state estimation by less than 25% relative to when general relativity is assumed, and determining the growth index to 8%. For weak lensing we examine the level of understanding needed of quasi- and nonlinear structure formation in modified gravity theories, and the trade off between stronger precision but greater susceptibility to bias as progressively more nonlinear information is used.
- OSTI ID:
- 20935218
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 75, Issue 2; Other Information: DOI: 10.1103/PhysRevD.75.023519; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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