  We construct a family of infinite-dimensional positive sub-coalgebras within
the Grothendieck ring of Hecke algebras, when viewed as a Hopf algebra with
respect to the induction and restriction functor. These sub-coalgebras have as
structure constants the 3-point genus zero Gromov-Witten invariants of
Grassmannians and are spanned by what we call cylindric Hecke characters, a
particular set of virtual characters for whose computation we give several
explicit combinatorial formulae. One of these expressions is a generalisation
of Ram's formula for irreducible Hecke characters and uses cylindric broken rim
hook tableaux. We show that the latter are in bijection with so-called `ice
configurations' on a cylindrical square lattice, which define the asymmetric
six-vertex model in statistical mechanics. A key ingredient of our construction
is an extension of the boson-fermion correspondence to Hecke algebras and
employing the latter we find new expressions for Jing's vertex operators of
Hall-Littlewood functions in terms of the six-vertex transfer matrices on the
infinite planar lattice.
