  We address the variational preparation of the Thermofield Double state (TFD)
as the ground state of a suitably engineered Hamiltonian acting on the doubled
Hilbert space. Through the use of the entanglement forging ansatz, we propose a
solution that involves only circuits of width $N$. We illustrate the method
with generic fermionic hamiltonians. The free fermion case can be solved in
closed form, and yields a warm start state for the variational circuits
whenever interactions are present.
