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Symmetry 2000
Entropy 2002, 4(3), 49-64; doi:10.3390/e4030049

Conformal Symmetry and Cosmological Entropy Production

1,*  and 2,*
1 Fachbereich Physik, Universit├Ąt Konstanz PF M678, D-78457 Konstanz, Germany 2 Department of General Relativity and Gravitation Kazan State University, 420008 Kazan, Russia
* Authors to whom correspondence should be addressed.
Received: 16 August 2001 / Accepted: 3 March 2002 / Published: 10 March 2002
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Introducing an effective refraction index of an isotropic cosmic medium, we investigate the cosmological fluid dynamics which is consistent with a conformal, timelike symmetry of a corresponding "optical" metric. We demonstrate that this kind of symmetry is compatible with the existence of a negative viscous pressure and, consequently, with cosmological entropy production. We establish an exactly solvable model according to which the viscous pressure is a consequence of a self-interacting one-particle force which is self-consistently exerted on the microscopic particles of a relativistic gas. Furthermore, we show that a suficiently high decay rate of the refraction index of an ultrarelativistic cosmic medium results in an in ationary expansion of the universe.
Keywords: general relativity; cosmology; thermohydrodynamics; kinetic theory; inflationary universe general relativity; cosmology; thermohydrodynamics; kinetic theory; inflationary universe
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Zimdahl, W.; Balakin, A.B. Conformal Symmetry and Cosmological Entropy Production. Entropy 2002, 4, 49-64.

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