# What Would We Learn by Detecting a Gravitational Wave Signal in the Cosmic Microwave Background Anisotropy

@article{Lyth1997WhatWW, title={What Would We Learn by Detecting a Gravitational Wave Signal in the Cosmic Microwave Background Anisotropy}, author={David H. Lyth}, journal={Physical Review Letters}, year={1997}, volume={78}, pages={1861-1863} }

Inflation generates gravitational waves, which may be observable in the low multipoles of the cosmic microwave background anisotropy but only if the inflaton field variation is at least of order the Planck scale. Such a large variation would imply that the model of inflation cannot be part of an ordinary extension of the standard model, and combined with the detection of the waves it would also suggest that the inflaton field cannot be one of the superstring moduli. Another implication of…

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## References

SHOWING 1-7 OF 7 REFERENCES

### For a recent proposal for m aki ng such an i denti cati on see

- 1995

### astro - ph / 9507001 ; T . T . Nakam ura and E . D . Stewart , astro - ph / 9604103 . [ 7 ] A . A . Starobinsky

- Sov . Astron . Lett .
- 1985

### To bepreci se, i ssm al lforany reasonabl e val uesofthe param etersi n si m pl e versi onsofhybri d i n ati on,and can be m ade sm al lw i thout ne-tuni ng i n m ore com pl i cated ones

### T he factor 1+ r has been i gnored because the predi cti on for H has errors [ 14]oforder r

### Phys . Lett . 108 B ( 1982 ) ; A .

- J . Steinhardt , Phys . Rev . Lett .

### Q . Sha and A .V i l enki n

- Phys. R ev. Lett
- 1982