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Identifying the inflaton with primordial gravitational waves
Damien A Easson1, Brian A Powell
1Department of Physics & School of Earth and Space Exploration & Beyond Center, Arizona State University, Tempe, Arizona 85287-1504, USA. easson@asu.edu
Physical Review Letters
|June 15, 2011
Summary
Experimental physics can reveal the gravitational Lagrangian of inflation. Precision measurements of primordial gravitational waves, specifically the tensor spectral index, can significantly reduce uncertainties in inflaton potentials, even without complex observables.
Area of Science:
- Cosmology
- Theoretical Physics
- Experimental Physics
Background:
- Inflationary cosmology describes the early universe's rapid expansion.
- The gravitational Lagrangian governs the dynamics of inflation.
- Current observations have large degeneracies in inflationary parameters.
Purpose of the Study:
- To investigate how experimental physics can constrain the inflationary gravitational Lagrangian.
- To determine if future observables can reduce parameter space degeneracy.
- To assess the impact of precision measurements on inflaton potential determination.
Main Methods:
- Analyzing the relationship between observables and the inflationary Lagrangian.
- Exploring the potential of future cosmological measurements (e.g., non-gaussianity, isocurvature modes).
- Investigating the impact of precise tensor spectral index measurements from primordial gravitational waves.
Main Results:
- Observable degeneracy in inflationary models is substantial.
- Future observables like non-gaussianity and isocurvature modes may reduce degeneracy.
- Precision measurement of the tensor spectral index can significantly constrain inflaton potentials, even without other advanced observables.
Conclusions:
- Experimental physics plays a crucial role in uncovering the inflationary gravitational Lagrangian.
- Direct detection of primordial gravitational waves and precise measurement of the tensor spectral index offer a powerful path to understanding inflation.
- Reducing parameter space degeneracy is achievable through targeted future observations.
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