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Chiral primordial gravitational waves from a Lifshitz point
Tomohiro Takahashi1, Jiro Soda
1Department of Physics, Kyoto University, Kyoto, 606-8501, Japan.
Physical Review Letters
|August 8, 2009
Summary
Primordial gravitational waves exhibit circular polarization, a robust prediction of quantum gravity at a Horava Lifshitz point. This chirality, arising from parity violation, offers testable signatures in cosmic microwave background radiation and gravitational wave observations.
Area of Science:
- Theoretical physics
- Cosmology
- Quantum gravity
Background:
- Inflationary cosmology predicts primordial gravitational waves.
- Quantum gravity theories aim to unify gravity with quantum mechanics.
- Horava Lifshitz gravity offers a potential framework for quantum gravity.
Purpose of the Study:
- Investigate the properties of primordial gravitational waves within Horava Lifshitz quantum gravity.
- Determine if parity violation occurs and its implications for gravitational waves.
- Explore testable predictions for observational cosmology.
Main Methods:
- Applying principles of power-counting renormalizability.
- Utilizing foliation-preserving diffeomorphism invariance.
- Imposing the detailed balance condition.
Main Results:
- Demonstrated that primordial gravitational waves are circularly polarized.
- Identified parity violation as the cause of circular polarization.
- Established chirality as a robust prediction of this quantum gravity model.
Conclusions:
- The chirality of primordial gravitational waves is a key prediction of quantum gravity at a Horava Lifshitz point.
- Observational tests using cosmic microwave background radiation and stochastic gravitational waves can verify this prediction.
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