1) The observer-dependent dark energy future event horizon is the Wheeler-Feynman total absorber. This needs the hologram Ansatz that the interior 3D + 1 bulk is a retrocausal hologram image of the 2D + 1 surrounding event horizon surface where our future light cone intersects it.
2) Roger Penrose's "spin frame" has two QUBIT spinors, which in the case of the null light cone tetrads of Einstein's gravity field, l, n, m & m* are advanced and retarded spinors with support on the past and future local light cones respectively. Note that the usual tetrads where the time component is along the world line of the observer-detector and a spacelike triad, consist in form of the Bell pair states of spinor QUBITs used all the time in quantum information/computer theory. This is why I use Wheeler's "IT FROM (Q) BIT."