[HN Gopher] Landauer's Principle
       ___________________________________________________________________
        
       Landauer's Principle
        
       Author : layer8
       Score  : 25 points
       Date   : 2023-05-27 19:04 UTC (1 days ago)
        
 (HTM) web link (en.wikipedia.org)
 (TXT) w3m dump (en.wikipedia.org)
        
       | sgdpk wrote:
       | Inspired by this, in my PhD we actually used a quantum computer
       | to do classical logic to investigate if that can lead to energy
       | savings [1]. Quantum machines are (in principle) reversible, so
       | they may avoid Landauer's principle.
       | 
       | However, there are subtle energy costs that you can hit before
       | getting to Landauer's. The most interesting to me is that the
       | qubits can become entangled with the wires that control them!
       | This reduces the quality of information, and one way around it is
       | to use a lot of energy [2].
       | 
       | [1] https://arxiv.org/abs/2210.10470
       | 
       | [2]
       | https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89...
        
       | sneak wrote:
       | If I understand this correctly, this puts an upper bound on the
       | computational ability of a Dyson sphere surrounding a star.
        
         | _a_a_a_ wrote:
         | dyson spheres compute?
        
           | icegreentea2 wrote:
           | They don't have to. You can interpret the original comment as
           | "puts an upper bound on the computational ability of a Dyson
           | sphere if it dedicated all captured energy to computation".
        
       | surprisetalk wrote:
       | ELI5: there's a lower bound on the physical heat required to
       | erase one bit of information
       | 
       | It's cool because it creates a relation between pure math
       | (information) and physics (entropy).
       | 
       | Maxwell's Daemon is useful context. In short, it's a thought
       | experiment about trying to "cheat" 2nd law of thermodynamics, and
       | Landauer's Principle pops up as a computational speed limit of
       | sorts.
       | 
       | [1] https://en.wikipedia.org/wiki/Maxwell%27s_demon
        
         | avmich wrote:
         | How reversible computing is related to it?
        
           | cleansingfire wrote:
           | Reversible computing cannot lose information or energy. No
           | dissipation allowed.
        
         | williamjackson wrote:
         | As a kid I always wondered where the name "Maxwell's Maniac"
         | came from.
         | 
         | https://gamicus.fandom.com/wiki/Maxwell%27s_Maniac
        
       ___________________________________________________________________
       (page generated 2023-05-28 23:00 UTC)