  Relativistic fermionic field theories constitute the fundamental description
of all observable matter. The simplest of the models provide a useful,
classically verifiable benchmark for noisy intermediate scale quantum
computers. We calculate the energy levels of the massive Thirring model - a
model of Dirac fermions with four-fermion interactions - on a lattice in 1 + 1
space-time dimensions. We employ a hybrid classical-quantum computation scheme
to obtain the mass gap in this model for three spatial sites. With error
mitigation the results are in good agreement with exact classical calculations.
Our calculations extend to the vicinity of the massless limit where chiral
symmetry emerges, however relative errors for quantum computations in this
regime are significant. We compare our results with an analytical calculation
using perturbation theory.
