Information erasure without an energy cost

[jimgraber]

Pay with angular momentum instead of energy?
What do the experts here think of this recent paper?
http://arxiv.org/abs/1004.5330v1
In particular can you really change the spin or angular momentum without changing the energy?
Would this also apply to ordinary momentum?
(Note the authors say there is an overall entropy cost.)
This paper really shook up my preconceptions.
TIA for any enlightenment.
Jim Graber

 

[Count Iblis]

I actually found it surprising that this is really a new non-trivial result that will likely be published in Phys. Rev. Lett. this year.

You can make changes in energy of the angular momentum reservoir arbitrarily small by making it sufficiently massive. But I think such considerations are just minor details to make the statement rigorous.

Entropy is a measure of the information needed to fully specify the state of a system and that doesn't have necessarily anything to do with energy. The result is, I guess, surprising to people who subscribe to the classical thermodynamics ideology.