Disformal transformations on the CMB
In this work we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts, such as Galileons theories or massive gravity, nevertheless the speed is very con...
| Main Authors: | , , |
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| Format: | Article |
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IOPScience
2016
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| Online Access: | https://eprints.nottingham.ac.uk/39508/ |
| _version_ | 1848795853210255360 |
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| author | Burrage, Clare Cespedes, Sebastian Davis, Anne-Christine |
| author_facet | Burrage, Clare Cespedes, Sebastian Davis, Anne-Christine |
| author_sort | Burrage, Clare |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | In this work we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts, such as Galileons theories or massive gravity, nevertheless the speed is very constrained to be one by observations of gravitational wave emission. It has been shown that in inflation a disformal trans- formation allows to set the speed for tensor modes to one without making changes to the curvature power spectrum. Here we show that this invariance does not hold when considering the CMB anisotropy power spectrum. It turns out that the after doing the transformation there is an imprint on the acoustic peaks and the diffusion damping. This has interesting consequences; here we explore quartic galileon theories which allow a modified speed for tensor modes. For these theories the transformation can be used to constraint the parameter space in different regimes |
| first_indexed | 2025-11-14T19:38:41Z |
| format | Article |
| id | nottingham-39508 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:38:41Z |
| publishDate | 2016 |
| publisher | IOPScience |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-395082020-05-04T18:07:10Z https://eprints.nottingham.ac.uk/39508/ Disformal transformations on the CMB Burrage, Clare Cespedes, Sebastian Davis, Anne-Christine In this work we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts, such as Galileons theories or massive gravity, nevertheless the speed is very constrained to be one by observations of gravitational wave emission. It has been shown that in inflation a disformal trans- formation allows to set the speed for tensor modes to one without making changes to the curvature power spectrum. Here we show that this invariance does not hold when considering the CMB anisotropy power spectrum. It turns out that the after doing the transformation there is an imprint on the acoustic peaks and the diffusion damping. This has interesting consequences; here we explore quartic galileon theories which allow a modified speed for tensor modes. For these theories the transformation can be used to constraint the parameter space in different regimes IOPScience 2016-08-11 Article PeerReviewed Burrage, Clare, Cespedes, Sebastian and Davis, Anne-Christine (2016) Disformal transformations on the CMB. Journal of Cosmology and Astroparticle Physics, 2016 . ISSN 1475-7516 http://iopscience.iop.org/article/10.1088/1475-7516/2016/08/024/meta doi:10.1088/1475-7516/2016/08/024 doi:10.1088/1475-7516/2016/08/024 |
| spellingShingle | Burrage, Clare Cespedes, Sebastian Davis, Anne-Christine Disformal transformations on the CMB |
| title | Disformal transformations on the CMB |
| title_full | Disformal transformations on the CMB |
| title_fullStr | Disformal transformations on the CMB |
| title_full_unstemmed | Disformal transformations on the CMB |
| title_short | Disformal transformations on the CMB |
| title_sort | disformal transformations on the cmb |
| url | https://eprints.nottingham.ac.uk/39508/ https://eprints.nottingham.ac.uk/39508/ https://eprints.nottingham.ac.uk/39508/ |