Correspondences between scalar field and fluid fluctuations in curved spacetime

Abstract

In this paper, a correspondence between scalar field fluctuations and generalized fluctuations in a hydrodynamic approximation of fields is obtained. The results presented here are of interest to field-fluid correspondences and form part of theoretical foundations in this area. The intention for such developments is to explore sub-hydro range mesoscopic physics for the relativistic fluids in curved spacetime. The fluid correspondences fall in the classical domain and can replace the quantum fields and fluctuations for scales around the hydrodynamic limits. This paper extends our earlier results with a more elaborate physical insight towards the quantum fluids and retention of partial quantum nature in a stochastic description in bulk of the fluids. This also accounts for nonthermal effects along with thermal and quantum fluctuations for the fields in the hydro limit. Hence, the expressions presented here are very general in nature for various applications. The further scope of research that such developments give is discussed in the concluding section.