The effective field theory of multi-component fluids

Article Article scientifique Article The effective field theory of multi-component fluids eng 2014 author Ballesteros Guillermo 791613 author Bellazzini Brando author Mercolli Lorenzo 007 10.1088/1475-7516/2014/05/007 1475-7516 1312.2957 We study the effective Lagrangian, at leading order in derivatives, that describes the propagation of density and metric fluctuations in a fluid composed by an arbitrary number of interacting components. Our results can be applied to any situation in cosmology where different species have non-gravitational interactions.In time-dependent backgrounds, such as FLRW, the quadratic action can only be diagonalized at fixed time slices and flavour mixing is unavoidable as time flows. In spite of this, the fluid can be interpreted at the level of the linear equations of motion as an ensemble of individual interacting species. We show that interactions lead to anisotropic stresses that depend on the mixing terms in the quadratic action for perturbations.In addition to the standard entrainment among different components, we find a new operator in the effective action that behaves as a cosmological constant when it dominates the dynamics. Dark energy theory Cosmological perturbation theory Dark matter theory Gravity Dewey 500.2 Open Access - SCOAP3 34 Département de physique nucléaire et corpusculaire 132 false Journal of cosmology and astroparticle physics 1405 05 f69b05d8-6266-431d-9853-154dd1eb2d68 Article (Published version) Public fulltext.pdf 491322 application/pdf CC BY openAccess Faculté des sciences / Section de physique / Département de physique nucléaire et corpusculaire

Title	Published in	Access level	OA Policy	Year	Views	Downloads

The effective field theory of multi-component fluids	Journal of cosmology and astroparticle physics			2014	581	341

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Ballesteros, Guillermo