No. You should think of reversible computers as quantitatively more efficient than normal computers, but basically the same thing. If you have polynomial time and energy then reversible computers still implement P.
My post observes that if the universe had a long enough lifetime, then a reversible computer would be able to compute PSPACE even if you only started out with polynomially much negentropy (whereas a normal computer would quickly burn up all the negentropy and leave you with a universe too hot to compute). So time and space and durability might be more important than you’d think relative to negentropy or free energy, and potentially the scale of computation done by our civilization will be much vaster than you would guess if you tried to do the entropy accounting.
Also see this underappreciated paper on “catalyticcomputing,” which points out that you can do some useful computations using physical degrees of freedom even without knowing the initial states of those degrees of freedom, i.e. a reversible computer could theoretically use a giant disordered system to do useful work even without free energy to initialize it.
No. You should think of reversible computers as quantitatively more efficient than normal computers, but basically the same thing. If you have polynomial time and energy then reversible computers still implement P.
My post observes that if the universe had a long enough lifetime, then a reversible computer would be able to compute PSPACE even if you only started out with polynomially much negentropy (whereas a normal computer would quickly burn up all the negentropy and leave you with a universe too hot to compute). So time and space and durability might be more important than you’d think relative to negentropy or free energy, and potentially the scale of computation done by our civilization will be much vaster than you would guess if you tried to do the entropy accounting.
Also see this underappreciated paper on “catalytic computing,” which points out that you can do some useful computations using physical degrees of freedom even without knowing the initial states of those degrees of freedom, i.e. a reversible computer could theoretically use a giant disordered system to do useful work even without free energy to initialize it.