Initial data of effective field theories of relativistic viscous fluids and gravity
Abstract
There has been recent progress in developing well-posed theories of relativistic viscous hydrodynamics and of gravitational effective field theories. These have in common the feature that they introduce unphysical degrees of freedom. We address the problem of how these should be treated. We propose a “reduction of order” approach which is applied not at the level of equations of motion but only to initial data. This specifies uniquely the data for the unphysical modes in terms of the data for the physical modes. We argue that the apparent breaking of Lorentz invariance associated with this approach is not a problem provided one restricts to Lorentz frames for which the assumptions of effective field theory are manifestly valid.
Fields of Study & Subjects
Material Science and Thermodynamics
Cosmology and Gravitation Theories
Fluid dynamics and aerodynamics studies
Publication details
- Journal / source
- Physical review. D/Physical review. D.
- Publisher
- American Physical Society (APS)
- Volume
- 113
- Issue
- 12
- Publication date
- 11 May 2026
- Language
- EN