Equation of state at a = 10⁻⁴ as a function of Q₀/𝒵₀ for the exponential 𝒦(Q) function for various masses m. This is for K_B = 0.1, H₀ = 70 km s⁻¹ Mpc⁻¹, and Ω₀ = 0.25. The dotted gray line shows the upper bound from Ilić et al. (2021). We note that m² is the prefactor of 𝒦(Q). Thus, both the density and the pressure are proportional to m² and this prefactor cancels in w. The dependence on m shown here comes from the constraint that the density parameter today is Ω₀.