



01367nas a2200157   4500008004100000245004300041210003700084260001500121300001200136490000900148520096000157100002301117700001801140700001401158856003701172       2014                        eng d00aThe Bose-Hubbard model is QMA-complete0 aBoseHubbard model is QMAcomplete  c2014/07/08  a308-3190 v85723 a  The Bose-Hubbard model is a system of interacting bosons that live on the
vertices of a graph. The particles can move between adjacent vertices and
experience a repulsive on-site interaction. The Hamiltonian is determined by a
choice of graph that specifies the geometry in which the particles move and
interact. We prove that approximating the ground energy of the Bose-Hubbard
model on a graph at fixed particle number is QMA-complete. In our QMA-hardness
proof, we encode the history of an n-qubit computation in the subspace with at
most one particle per site (i.e., hard-core bosons). This feature, along with
the well-known mapping between hard-core bosons and spin systems, lets us prove
a related result for a class of 2-local Hamiltonians defined by graphs that
generalizes the XY model. By avoiding the use of perturbation theory in our
analysis, we circumvent the need to multiply terms in the Hamiltonian by large
coefficients.
1 aChilds, Andrew, M.1 aGosset, David1 aWebb, Zak  uhttp://arxiv.org/abs/1311.3297v1