see: THIS: and below, which is in line with Quantum FFF Theory
see under: "Dark energy and the swampland"
"More recently, researchers have proposed additional swampland criteria in response to difficulties in explaining dark energy within string theory [8, 9]. These conjectures are still being debated among string theorists, but if they are true, they lead to predictions about the cosmic expansion history that may be tested in the near future [7, 10]. The conjectures relate to models of dark energy that involve a scalar field φ, which can be thought of as something like the Higgs field. The field φ can be the source of dark energy, in the sense that the field’s potential V(φ) is equal to the density of dark energy Λ. String theory calculations have suggested that the slope of this potential, V′, must be nonzero. Specifically, the slope should satisfy the inequality ∣∣V′∣∣>cVMP>0, where c is a number of order unity, at least for large values of the field."
"If the above inequality is correct, it implies that dark energy is not a cosmological constant as many cosmologists assume. The alternative to a cosmological constant is a dark energy that is changing over time. Current observational constraints are consistent with this model of dark energy as long as c < 0.5, and future observations of the variation of dark energy can potentially detect or put further bounds on c (Fig. 3).below:"
Vafa's String interpretation lines of dark energy decline. in contrast with the supernova relation found by redshift measurement
"This graph shows the equation of state parameter w, which characterizes dark energy density as a function of cosmological redshift z. If dark energy is defined by the cosmological constant, then w=−1. The black line is the upper bound on w from observations of supernovae, the cosmic microwave background, and the galaxy distribution. The colored curves are string theory predictions for dark energy for different values of c; see text. Show Less"
For Quantum-FFF Theory see: http://vixra.org/author/leo_vuyk
and: "The Alternative Origin of Hubble Redshift : Vacuum Absorption by black holes as a Support for Quantum Dipole Repeller Gravity and a Contracting Universe." http://vixra.org/pdf/1702.0040v3.pdf
As a logic assumption, The origin of the Hubble controversy according to Q-FFF Theory is,
That the local Dark Energy ( in the form of an oscillating Planck lattice) is decreasing into the direction of the CMB, by the increased longer duration effect of Dark Matter Black Holes vacuum absorption, started direct in the Big Bang BH splitting/ evaporation process. called: DM BH Planck Length elongation effect. (see image above) .