Onsager reciprocal relations with broken time-reversal symmetry

This paper shows that Onsager reciprocal relations remain valid even in presence of a generic magnetic field so that the time reversal symmetry is broken. The authors prove that breaking the time reversal symmetry does not remove the thermodynamic constraints imposed by the Onsager relations on heat to work conversion. In particular, the possibility of an engine operating at the Carnot efficiency with finite power is ruled out on purely thermodynamic grounds