Revisiting interpolating flows in ( 1+1 ) hydrodynamics

We revisit the general analytic solution space for relativistic (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>1</a:mn><a:mo>+</a:mo><a:mn>1</a:mn></a:mrow></a:math>)-dimensional hydrodynamics for a perfect fluid flowing along the longitudinal direction. We work out the explicit one-parameter family of interpolating flows between boost-invariant and boost-noninvariant regimes, where a direct and simple dialing of the parameter at the level of solutions is possible. We also discuss the construction of generalized rapidity distribution of entropy for such interpolating flows at the level of potentials.