  Thermal properties of quantum fields at finite temperature are crucial to
understanding strongly interacting matter and recent development in quantum
computing has provided an alternative and promising avenue of study. In this
work, we study thermal field theories involving only fermions using quantum
algorithms. We first delve into the presentations of fermion fields via qubits
on digital quantum computers alongside the quantum algorithms such as quantum
imaginary time evolutions employed to evaluate thermal properties of generic
quantum field theories. Specifically, we show numerical results such as the
thermal distribution and the energy density of thermal field theories for
Majorana fermions in 1+1 dimensions using quantum simulators. In addition to
free field theory, we also study the effects of interactions resulting from
coupling with a spatially homogeneous Majorana field. In both cases, we show
analytically that thermal properties of the system can be described using
phase-space distributions, and the quantum simulation results agree with
analytical and semiclassical expectations. Our work is an important step to
understand thermal fixed points, preparing for quantum simulation of
thermalization in real time.
