We ask if it is possible to make the high-density zero-point fields re
quired by quantum theory compatible with the low-density cosmological
models of general relativity. (This is a generalization of what is som
etimes called the problem of the cosmological constant.) If there is a
cosmological zero-point field, it must possess the equation of state
3p(z) + rho(z)c2 = 0 in order to preserve the motions of the galaxies.
(Here, p(z) is pressure, rho(z) is density, and c is the speed of lig
ht; this equation of state is the limiting form of those popular in in
flationary cosmology.) We examine a two-fluid model, where a zero-poin
t fluid with this equation of state coexists with a fluid of galaxies
with the usual dust equation of state and Einstein-de Sitter dynamics.
Both components of the fluid obey the first law of thermodynamics, as
required by energy conservation. However, to be otherwise acceptable,
the zero-point fluid's strong curvature effects would have to be ''re
normalized,'' and its high energy density would have to be isolated fr
om ordinary matter to preserve the isotropy of the 3 K microwave backg
round. These are significant problems and will need further study.