TY - JOUR

T1 - Universality classes of relativistic fluid dynamics

T2 - Applications

AU - Gavassino, L.

AU - Disconzi, M.

AU - Noronha, J.

N1 - Publisher Copyright:
© 2024 American Physical Society.

PY - 2024/5/1

Y1 - 2024/5/1

N2 - Using a formalism that was recently developed in a companion Letter, we rigorously prove the equivalence, in the linear regime, of a number of apparently different relativistic hydrodynamic theories proposed in the literature. In particular, we show that Hydro+ is indistinguishable from the Israel-Stewart theory for bulk viscosity, which in turn is indistinguishable from a reacting mixture. The two-fluid model for superfluidity coincides with the Israel-Stewart theory for heat conduction in the limit of infinite conductivity, and this explains why the latter has a second sound. Also, MIS∗ is equivalent to the Burgers model for viscoelasticity, and this implies that the former must exhibit an elastic behavior at high frequencies. Additionally, we show that if the degrees of freedom and the conservation laws of a hydrodynamic theory have the same geometric character as those of the Israel-Stewart theory, then such theory must be indistinguishable from the Israel-Stewart theory in the linear regime. This explains why all second-order theories turn out to be identical near equilibrium. Finally, we construct the first linearized model, to our knowledge, for a relativistic supersolid that is proven to be causal, stable, and strongly hyperbolic.

AB - Using a formalism that was recently developed in a companion Letter, we rigorously prove the equivalence, in the linear regime, of a number of apparently different relativistic hydrodynamic theories proposed in the literature. In particular, we show that Hydro+ is indistinguishable from the Israel-Stewart theory for bulk viscosity, which in turn is indistinguishable from a reacting mixture. The two-fluid model for superfluidity coincides with the Israel-Stewart theory for heat conduction in the limit of infinite conductivity, and this explains why the latter has a second sound. Also, MIS∗ is equivalent to the Burgers model for viscoelasticity, and this implies that the former must exhibit an elastic behavior at high frequencies. Additionally, we show that if the degrees of freedom and the conservation laws of a hydrodynamic theory have the same geometric character as those of the Israel-Stewart theory, then such theory must be indistinguishable from the Israel-Stewart theory in the linear regime. This explains why all second-order theories turn out to be identical near equilibrium. Finally, we construct the first linearized model, to our knowledge, for a relativistic supersolid that is proven to be causal, stable, and strongly hyperbolic.

UR - http://www.scopus.com/inward/record.url?scp=85195066759&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85195066759&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.109.096041

DO - 10.1103/PhysRevD.109.096041

M3 - Article

AN - SCOPUS:85195066759

SN - 2470-0010

VL - 109

JO - Physical Review D

JF - Physical Review D

IS - 9

M1 - 096041

ER -