  We explore further the Hamiltonian formulation of Yang-Mills theory in 2+1
dimensions in terms of gauge-invariant matrix variables. Coupling to scalar
matter fields is discussed in terms of gauge-invariant fields. We analyze how
the screening of adjoint (and other screenable) representations can arise in
this formalism. A Schrodinger equation is then derived for the gluelump states
which are the daughter states when an adjoint string breaks. A variational
solution of this Schrodinger equation leads to an analytic estimate of the
string-breaking energy which is within 8.8% of the latest lattice estimates.
