When electric current passes through a copper wire, it gets heated, this is the famous Joule effect. The explanation for this is given as follows: Free electrons in the copper wire move very fast and "collide" with each other, thereby generating heat.
But we know that electrons are quantum objects. According to quantum mechanics they are neither particles nor waves.
How do we explain the Joule heating effect according to quantum mechanics? What we call "Joule heat" must be an exceedingly large amount of photons (coming out of the surface of the copper wire) of infra-red radiation due to accelerations of copper electrons. Am I correct?