Can the clustered dark matter and the smooth dark energy arise from the same scalar field?

Cosmological observations suggest the existence of two different kinds of energy densities dominating at small (less than or similar to500 Mpc) and large (greater than or similar to1000 Mpc) scales. The dark matter component, which dominates at small scales, contributes Omega(m)approximate to0.35 and has an equation of state p=0, while the dark energy component, which dominates at large scales, contributes Omega(V)approximate to0.65 and has an equation of state psimilar or equal to-rho. It is usual to postulate weakly interacting massive particles (WIMPs) for the first component and some form of scalar field or cosmological constant for the second component. We explore the possibility of a scalar field with a Lagrangian L=-V(phi)root1-partial derivative(i)phipartial derivative(i)phi acting as both clustered dark matter and smoother dark energy and having a scale-dependent equation of state. This model predicts a relation between the ratio r=rho(V)/rho(DM) of the energy densities of the two dark components and an expansion rate n of the universe [with a(t)proportional tot(n)] in the form n=(2/3)(1+r). For rapproximate to2, we get napproximate to2 which is consistent with observations.