  A Quantum Energy Inequality (QEI) is derived for the massive Ising model,
giving a state-independent lower bound on suitable averages of the energy
density; the first QEI to be established for an interacting quantum field
theory with nontrivial S-matrix. It is shown that the Ising model has
one-particle states with locally negative energy densities, and that the energy
density operator is not additive with respect to combination of one-particle
states into multi-particle configurations.
