> On 1 May 2019, at 10:56, cloudver...@gmail.com wrote: > > > > By "heat" I just mean it as one studies it as a subject in a physics class, > for example. > - https://en.wikipedia.org/wiki/Heat <https://en.wikipedia.org/wiki/Heat> > > Does all computation generate heat? > > (Should be a simple enough question, I think.)
Hmm… Not that simple. In the 1950s, Hao Wang has given the first proof that there exist universal machine working in a completely reversible way, without any erasing of information. Wang was a mathematical logicien, and his result was ignored. In 1961, Landauer, a physicist, working on the Maxwell Daemon problem, discovered that the only computational process that generates heat is the erasure. To erase 1 bit of information Landauer shows that you need to dissipate at least kTln(2) energy, with k the Boltzman constant and T the temperature. So, in principle, given Hao Wang + Landauer, we can build a machine doing computation without using, nor dissipating any energy, except for the start and ending of the computation. Then, most algorithm in quantum computing require full reversibility, and should work with very few amount of energy, except similarly for the local read and write, or starting vs stopping behaviour. Both from mechanism and physics, I conjecture that there is a core physical reality which is a BCI algebra, which means no erasure of information, and no duplication of information. This CANNOT be Turing universal, and it is unclear to me which of erasure and duplication can be truly physical. It is just well above the scope of the present knowledge of the machine’s physics to answer this, and among physicians, this leads to discussion of black hole, non cloning theorem, etc. Open problem for me. Of course, in arithmetic, no computation at all use energy, given that they use only the arithmetical truth, which are out of time and space, and any physical category. The physics emerge from this, as an invariant pattern for all Turing universal observation, defined by a sort of bet on first person experiences. Energy should be retrieved from that Core physics. I speculate that the Monster Group plays a role here. Bruno > > - @philipthrift > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com > <mailto:everything-list+unsubscr...@googlegroups.com>. > To post to this group, send email to everything-list@googlegroups.com > <mailto:everything-list@googlegroups.com>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
