Quantum origin of Ohm's reciprocity relation and its violation: conductivity as inverse resistivity

Conventional wisdom teaches us that the electrical conductivity in a material is the inverse of its resistivity. In this work, we show that when both of these transport coefficients are defined in linear response through the Kubo formulae as two-point correlators of quantum fields, this Ohm's reciprocity relation is generically violated in theories with dynamical electromagnetism. We also elucidate how in special limits (e.g., in the DC limit in the presence of thermal effects, in certain 2+1d conformal theories, and in holographic supersymmetric theories) the reciprocity is again reinstated, and show that if the response of a material is measured with respect to the total electric field that includes quantum corrections, then the reciprocity relation is satisfied by definition. However, in that case, the transport coefficients are given by the photon vacuum polarisation and not the correlators of conserved currents that dominate macroscopic late-time transport.