  Central to the normal state of cuprate high-temperature superconductors is
the collapse of the pseudogap, briefly reviewed here, at a critical point and
the subsequent onset of the strange-metal characterized by a resistivity that
scales linearly with temperature. A possible clue to the resolution of this
problem is the inter-relation between two facts: 1) A robust theory of T-linear
resistivity resulting from quantum criticality requires an additional length
scale outside the standard 1-parameter scaling scenario and 2) breaking the
Landau correspondence between the Fermi gas and an interacting system with
short-range repulsions requires non-fermionic degrees. We show that a
low-energy theory of the Hubbard model which correctly incorporates dynamical
spectral weight transfer has the extra degrees of freedom needed to describe
this physics. The degrees of freedom that mix into the lower band as a result
of dynamical spectral weight transfer are shown to either decouple beyond a
critical doping, thereby signaling Mottness collapse or unbind above a critical
temperature yielding strange metal behaviour characterised by $T-$linear
resistivity.
