Atypical k-essence cosmologies
We analyze the implications of having a divergent speed of sound in k-essence cosmological models. We first study a known theory of that kind, for which the Lagrangian density depends linearly on the time derivative of the k-field. We show that when k-essence is the only source consistency requires...
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todo:paper_15507998_v71_n2_p023505_Chimento2023-10-03T16:23:57Z Atypical k-essence cosmologies Chimento, L.P. Lazkoz, R. article cosmological phenomena cosmos density langrangian model mathematical model power law solution problem solving rigidity sound velocity We analyze the implications of having a divergent speed of sound in k-essence cosmological models. We first study a known theory of that kind, for which the Lagrangian density depends linearly on the time derivative of the k-field. We show that when k-essence is the only source consistency requires that the potential of the k-field be of the inverse square form. Then, we review the known result that the corresponding power-law solutions can be mapped to power-law solutions of theories with no divergence in the speed of sound. After that, we argue that the requirement of a divergent sound speed at some point fixes uniquely the form of the Lagrangian to be exactly the one considered earlier and prove the asymptotic stability of the most interesting solutions belonging to the divergent theory. Then, we discuss the implications of having not just k-essence but also matter. This is interesting because introducing another component breaks the rigidity of the theory, and the form of the potential ceases to be unique as happened in the pure k-essence case. Finally, we show the finiteness of the effective sound speed under an appropiate definition. © 2005 The American Physical Society. Fil:Chimento, L.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_15507998_v71_n2_p023505_Chimento |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
article cosmological phenomena cosmos density langrangian model mathematical model power law solution problem solving rigidity sound velocity |
| spellingShingle |
article cosmological phenomena cosmos density langrangian model mathematical model power law solution problem solving rigidity sound velocity Chimento, L.P. Lazkoz, R. Atypical k-essence cosmologies |
| topic_facet |
article cosmological phenomena cosmos density langrangian model mathematical model power law solution problem solving rigidity sound velocity |
| description |
We analyze the implications of having a divergent speed of sound in k-essence cosmological models. We first study a known theory of that kind, for which the Lagrangian density depends linearly on the time derivative of the k-field. We show that when k-essence is the only source consistency requires that the potential of the k-field be of the inverse square form. Then, we review the known result that the corresponding power-law solutions can be mapped to power-law solutions of theories with no divergence in the speed of sound. After that, we argue that the requirement of a divergent sound speed at some point fixes uniquely the form of the Lagrangian to be exactly the one considered earlier and prove the asymptotic stability of the most interesting solutions belonging to the divergent theory. Then, we discuss the implications of having not just k-essence but also matter. This is interesting because introducing another component breaks the rigidity of the theory, and the form of the potential ceases to be unique as happened in the pure k-essence case. Finally, we show the finiteness of the effective sound speed under an appropiate definition. © 2005 The American Physical Society. |
| format |
JOUR |
| author |
Chimento, L.P. Lazkoz, R. |
| author_facet |
Chimento, L.P. Lazkoz, R. |
| author_sort |
Chimento, L.P. |
| title |
Atypical k-essence cosmologies |
| title_short |
Atypical k-essence cosmologies |
| title_full |
Atypical k-essence cosmologies |
| title_fullStr |
Atypical k-essence cosmologies |
| title_full_unstemmed |
Atypical k-essence cosmologies |
| title_sort |
atypical k-essence cosmologies |
| url |
http://hdl.handle.net/20.500.12110/paper_15507998_v71_n2_p023505_Chimento |
| work_keys_str_mv |
AT chimentolp atypicalkessencecosmologies AT lazkozr atypicalkessencecosmologies |
| _version_ |
1807321879668588544 |