  In this paper we present the detailed calculation of a new modular
Hamiltonian, namely that of a chiral fermion on a circle at non-zero
temperature. We provide explicit results for an arbitrary collection of
intervals, which we discuss at length by checking against known results in
different limits and by computing the associated modular flow. We also compute
the entanglement entropy, and we obtain a simple expression for it which
appears to be more manageable than those already existing in the literature.
