Abstract:
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.
Registro:
Documento: |
Artículo
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Título: | Atypical k-essence cosmologies |
Autor: | Chimento, L.P.; Lazkoz, R. |
Filiación: | Dpto. de Física, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina Fis. Teorikoa eta Zientziaren H. S., Zientzia eta Teknol. Fakultatea, Euskal Herriko Unibertsitatea, 644 Posta Kutxatila, 48080 Bilbao, Spain
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Palabras clave: | article; cosmological phenomena; cosmos; density; langrangian model; mathematical model; power law solution; problem solving; rigidity; sound; velocity |
Año: | 2005
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Volumen: | 71
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Número: | 2
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Página de inicio: | 023505
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Página de fin: | 1-023505-7
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DOI: |
http://dx.doi.org/10.1103/PhysRevD.71.023505 |
Título revista: | Physical Review D - Particles, Fields, Gravitation and Cosmology
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Título revista abreviado: | Phys Rev D Part Fields Gravit Cosmol
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ISSN: | 15507998
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CODEN: | PRVDA
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Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15507998_v71_n2_p023505_Chimento |
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Citas:
---------- APA ----------
Chimento, L.P. & Lazkoz, R.
(2005)
. Atypical k-essence cosmologies. Physical Review D - Particles, Fields, Gravitation and Cosmology, 71(2), 023505-1-023505-7.
http://dx.doi.org/10.1103/PhysRevD.71.023505---------- CHICAGO ----------
Chimento, L.P., Lazkoz, R.
"Atypical k-essence cosmologies"
. Physical Review D - Particles, Fields, Gravitation and Cosmology 71, no. 2
(2005) : 023505-1-023505-7.
http://dx.doi.org/10.1103/PhysRevD.71.023505---------- MLA ----------
Chimento, L.P., Lazkoz, R.
"Atypical k-essence cosmologies"
. Physical Review D - Particles, Fields, Gravitation and Cosmology, vol. 71, no. 2, 2005, pp. 023505-1-023505-7.
http://dx.doi.org/10.1103/PhysRevD.71.023505---------- VANCOUVER ----------
Chimento, L.P., Lazkoz, R. Atypical k-essence cosmologies. Phys Rev D Part Fields Gravit Cosmol. 2005;71(2):023505-1-023505-7.
http://dx.doi.org/10.1103/PhysRevD.71.023505