The rise of the superstring/M theory and brane cosmology enables the
physicists to be free of the fettering of the 4-d spacetime and provides a
whole new visual angle for the CC problem. To know what can we see from this
new visual angle, let us recall the main line of deduction on the CC
problem: SUSY breaking at TeV scale → the CC bigger than the observed value
by the orders of 60 → the radius of the Universe at the order of the
millimeter. In this reasoning, the estimate of the SUSY energy scale comes
from the synthetic analysis of the experiments and theories of high-energy
physics in existence. The notably downward adjusting of this scale will make
it contradict with the fact that no superpartner was observed in the high-
energy experiments and observations, while the upward adjusting of this
scale will increase the predicted value of the CC, making it further deviate
from the observations. It seems that there is no room of the energy scale
left to accommodate the ZP energy density corresponding to the CC. However,
an interesting question rises as follows: Which part of the space do we
refer in high dimensional theory when we talk about the space curvature
induced by the CC? Bethink of this, one can readily find that an additional
assumption implicitly assumed in the above deduction line: The space
curvature induced by the CC must appear in the observed Universe we live in.
This is certainly true for the 4-d theory since obviously the default space
in conventional cosmology is nothing but the 3-d space we live in. The
situation changes, however, in brane cosmology in which the space has the
dimensions up to ten. It is very likely that the curvature can occur only in
a part of dimensions of the whole bulk spacetime. Specifically, the CC
problem can be solved by imaging that the curvature induced by the CC occurs
only in the EDs while the whole observed Universe remains flat. This is so
because a homogeneous energy-momentum distribution—the CC—is not puzzle by
itself whereas it is the observable space-curvature effect thereby induced
that is the problem what we must face. If this scenario is true, then the
most sharp discrepancy in the CC problem and the problem of gauge-theory
scale with the observations mentioned above can be well eliminated.
A conjecture, given by Schmidhuber, suggests that in superstring theory (
specifically, in higher-dimensional supergravity) there exists such a
solution that the SUSY on our brane breaks at TeV scale while the SUSY in 4-
d supersurface outside of the brane, which is away a certain distance from
and parallel with the brane, remains exact.
这段话虽然提到了 Schmidhuber 的工作 (只是 Schmidhuber 工作的一部分), 但将之
与未标明出处的上下文的其它观点连在一起, 给人的印象是陈是一连串 idea 的提出
者, Schmidhuber 的工作可以作为对他 idea 的支持。