  We present a technique to compute the microcanonical thermodynamical
properties of a manybody quantum system using tensor networks. The Density Of
States (DOS), and more general spectral properties, are evaluated by means of a
Hubbard-Stratonovich transformation performed on top of a real-time evolution,
which is carried out via numerical methods based on tensor networks. As a
consequence, the free energy and thermal averages can be also calculated. We
test this approach on the one-dimensional Ising and Fermi-Hubbard models. Using
matrix product states, we show that the thermodynamical quantities as a
function of temperature are in very good agreement with the exact results. This
approach can be extended to higher-dimensional system by properly employing
other types of tensor networks.
