Undergrad Magnetic fields are exceptions to the second law of thermodynamics?

[shvitzed]

Einstein famously said “{Thermodynamics} is the only physical theory of universal content, which I am convinced, that within the framework of applicability of its basic concepts will never be overthrown.”

I don't think any of us want to argue with Einstein, but it's worth noting the "within the framework of applicability of its basic concepts" part of this quote. Specifically I am wondering about in the presence of perpendicular electric and magnetic fields, because at the microscopic level the motion of particles is not time symmetric and Onsager specified that magnetic fields are excluded from reciprocal relations: "the principle of dynamical reversibility does not apply when (external) magnetic fields or Coriolis forces are present", in which case "the reciprocal relations break down".[1] (https://en.wikipedia.org/wiki/Onsager_reciprocal_relations)

This would seem like a big deal if the second law of thermodynamics does not apply in this setting of perpendicular electric and magnetic fields. Is there a rational explanation for something I have gotten wrong here, or is there a reason why this hasn't been pursued more by researchers?

 

[vanhees71]

The 2nd law of thermodynamics or rather Boltzmann's H theorem does not rely on time-reversal symmetry of the fundamental physical laws but only need the unitarity of the S-matrix. Thus it also holds at presence of electromagnetic fields.

 

[shvitzed]

The 2nd law of thermodynamics or rather Boltzmann's H theorem does not rely on time-reversal symmetry of the fundamental physical laws but only need the unitarity of the S-matrix. Thus it also holds at presence of electromagnetic fields.

Thanks, it seems like in this other post you had replied with a more detailed reply on this topic: https://www.physicsforums.com/threads/unitarity-and-thermodynamics.860178/

Let me know if you happen to know of other sources for this topic worth referencing.