Field Theories and Fluids for an Interacting Dark Sector

Abstract

We consider the relationship between fluid models of an interacting dark sector, and the field theoretical models that underlie such descriptions. This question is particularly important in light of suggestions that such interactions may help alleviate a number of current tensions between different cosmological datasets. We construct consistent field theory models for an interacting dark sector that behave exactly like the coupled fluid ones, even at the level of linear perturbations, and can be trusted deep in the nonlinear regime. As a specific example, we focus on the case of a Dirac, Born-Infeld (DBI) field conformally coupled to a quintessence field. We show that the fluid linear regime breaks before the field gradients become large; this means that the field theory is valid inside a large region of the fluid nonlinear regime.

Corrections made and typos fixed in Section 3 & 4

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Cited by in corpus (11)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• An Effective Sign Switching Dark Energy: Lotka-Volterra Model of Two Interacting Fluids
• Observational constraints and predictions of the interacting dark sector with field-fluid mapping
• Cosmological perturbations in the interacting dark sector: Mapping fields and fluids
• Scalar field dark matter and dark energy: a hybrid model for the dark sector
• Electron mass variation from dark sector interactions and compatibility with cosmological observations
• Effective dark energy through spin-gravity coupling
• Phantom Dirac-Born-Infeld Dark Energy
• Consistent energy-momentum trace couplings of fluids
• Generation of CMB and Cosmological constant via bulk viscosity
• Revisiting cosmological diffusion models in Unimodular Gravity and the $H_0$ tension