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About the Power Spectrum Of Primordial Gravitational Waves

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Abstract

The primordial gravitational waves (PGW) have been generated by inflationary amplification of the primordial (quantum) fluctuations. It is true that they have not been recorded directly so far, but their spectrum can help a lot in solving the basic puzzles of the early universe as Inflation (high) energy scale. In the present work, we give a straightforward method to calculate the spectral energy density (SED) of the relic gravitons different from that used in e.g. Jinno et al. JCAP 1, 41 (2014), Boyle and Steinhardt, Phys. Rev. D 77, 063504 (2008) and Watanabe and Komatsu, Phys. Rev. D 73, 123515 (2006). In our approach, the evolution equations are in terms of the scale factor (instead of conformal time) through the Lagrange formalism (instead of the transfer function). The presence of the Hubble parameter allows to calculate the power spectrum in the different dynamical regimes.

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Notes

  1. Since, the first order of hij are considered and also hii = 0, then \( \sqrt {-g} = \sqrt {-\bar {g}}\).

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Acknowledgements

We thank K. Rezazadeh for useful discussions.

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Authors and Affiliations

  1. Department of Physics, University of Kurdistan, P.O.Box 66177-15175, Sanandaj, Iran

    Taimur Mohammadi, Behrooz Malekolkalami & Khabat Ghamari

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  1. Taimur Mohammadi
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  2. Behrooz Malekolkalami
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  3. Khabat Ghamari
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Correspondence to Taimur Mohammadi.

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Mohammadi, T., Malekolkalami, B. & Ghamari, K. About the Power Spectrum Of Primordial Gravitational Waves. Int J Theor Phys 61, 15 (2022). https://doi.org/10.1007/s10773-022-04982-6

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  • DOI: https://doi.org/10.1007/s10773-022-04982-6

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