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I've long been enamored with the idea of learning from analog computers to build the next generation of digital ones. In some perspective all our computers are
by EricBurnett 4y ago
I've long been enamored with the idea of learning from analog computers to build the next generation of digital ones. In some perspective all our computers are analog, of a sort - today's computer chips are effectively leveraging electron flow through a carefully arranged metal/silicon substrate, with self-interference via electromagnetic fields used to construct transistors and build up higher order logic units. We're now working on photonic computers, presumably with some new property leading to self interference, and allowing transistors/logic above that.
"Wires" are a useful convenience in the electron world, to build pathways that don't degrade with the passing of the elections themselves. But if we relax that constraint a bit, are there other ways we can build up arrangements of "organized flow" sufficient to have logic units arise? E.g. imagine pressure waves in a fluid -filled container, with mini barriers throughout defining the possible flow arrangement that allows for interesting self-reflections. Or way further out, could we use gravitational waves through some dense substance with carefully arranged holes, self-interfering via their effect on space-time, to do computations for us? And maybe before we get there, is there a way we could capitalize on the strong or weak nuclear force to "arrange" higher frequency logical computations to happen?
Physics permits all sorts of interactions, and we only really use the simple/easy-to-conceptualize ones as yet, which I hope and believe leaves lots more for us to grow into yet :).
- sandworm101 4y agoElectricity is also a wave. The wires are essentially waveguides for particles/waves traveling at near luminal speeds. So in theory anything done with electricity could be replicated using other waves, but to make it faster you would need waves that travel faster than electrons through a wire. Photons through a vacuum might be marginally faster, but pressure waves though a fluid would not. If bitflips are a problem in a modern chip, imagine the number of problems if your computer ran on gravity waves. The background hum of billions of star collisions cannot be blocked out with grounded tinfoil. There is no concept of a faraday cage for gravity waves.
- lupire 4y agoGravity is a poor source of computation because it is incredibly weak - 10^-43 vs electron force. Even if you add several powers of 10 for all the metal wire harness and battery chemistry around the electrons, you still get far more usable force per gram from electricity and metal than you do from gravity.
- otikik 4y agoThink Big. A computer that’s also a Galaxy.
- alephxyz 4y agoWith latency measurable in millennias
- cjsawyer 4y agoHave we checked to see if this is already the case?
- PeterisP 4y agoThat doesn't change the tradeoff; in a Big computer that's also a galaxy any of the stars used as an instrument for gravitational computation can't provide nearly as much compute as having a planet-sized electronic computer powered by that star.
- otikik 4y agoYeah but there are other factors. Resilience for example. A simple black hole approaches the trajectory of that planet sized-computer and plop! All that computation gets condensed to 3 single numbers and all the information is lost (that last part is a very hot topic). For a Galaxy computer on the other hand, blackholes could be the NOT gates.
- markisus 4y agoIs it even theoretically possible to waveguide gravity? The electric field can be positive and negative, but gravity is unsigned -- there is no anti-gravity. This is probably related to what you're saying about faraday cages.
- Optimal_Persona 4y agoIt's not unsigned, if you look on the back it says "Come together, you all. Love, The Universe." ;-)
- robotresearcher 4y agoGravity is antigravity if you run time backwards.
- palmtree3000 4y agoI realize this is a joke, but it isn't! Play a video of a ball flying up and then back down again and it'll be the same forward or backwards (up to air friction anyway).
- robotresearcher 4y agoIt wasn't a joke.
- PeterisP 4y agoIf it wasn't a joke, then that was simply a misleading false statement. Let's take the simple example of earth orbiting around the sun. Playing time backwards gets you a orbit in the opposite direction, while gravity becoming antigravity would mean that earth would get repelled by the sun and thus go off to infinity.
- robotresearcher 4y ago
- altruios 4y agoA faraday cage for gravity waves would be awesome... I mean - computers are nice - but you hit the nail on the head for revolutionary tech.
- stochtastic 4y agoNitpick: gravity waves [1] pretty universally refer to waves in fluid media in which the restoring force is buoyancy. Ripples in spacetime are usually called _gravitational_ waves. [1] https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave [2] https://en.wikipedia.org/wiki/Gravitational_wave https://en.wikipedia.org/wiki/Gravitational_wave
- EricBurnett 4y agoYou're right that the speed of light remains a constant limitation on propagation delay, but the defining limitation on the speed of computation is rather the clock speed - how long it takes for each round of computation. Electrons are comparatively slow due to the time it takes to fill and stabilize a transistor. Our hypothetical new type of computer will have to be faster to converge, rather than faster to propagate. You're right about the bit flips though. I don't know if a gravitational wave computer is actually ever going to be feasible, just an interesting dream for the far future. Hopefully there are more options to consider in the meantime :).
- ethn 4y agoElectricity travels faster than the speed of electrons (which only travel at ~3 cm/s!), it travels proportional to the speed of light, it’s speed is instead described by the Poynting vector, an energy wave.
- gaze 4y agoNo -- electrons travel at the Fermi velocity, which is about a tenth of the speed of light. You're talking about the drift velocity.
- ethn 4y ago??? Indeed everything I have written is accurate, not sure your point since we are talking about electron directional velocity in a wire not the speed of energy propagation... > In fact, electrons in conductive media do not travel at c, they travel at incredibly slow velocities, on the order of a fraction of a millimeter per second. The rate can vary, and the amount of current in the conductor is a function of the average speed of the electrons in it. [1] [1] https://wiki.c2.com/?SpeedOfElectrons https://wiki.c2.com/?SpeedOfElectrons [2] https://en.wikipedia.org/wiki/Drift_velocity https://en.wikipedia.org/wiki/Drift_velocity [3] https://physics.stackexchange.com/questions/497916/how-fast-does-an-electron-move https://physics.stackexchange.com/questions/497916/how-fast-...
- gaze 4y agoLinks [1] and [3] are wrong, and link [2] is correct but has nothing to do with this discussion. Link [1] is so full of errors it isn't even worth discussing. The pingpong ball analogy is wrong--it's all wrong. Link [3] commits the sin of ascribing single-electron behavior to parameters extracted from the Drude model. This is a semiclassical analogy and worked essentially thanks to units. Here's the link you're looking for. http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/Fermi.html http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/Fermi.html . Two electrons can't occupy the same state. In a metal of finite size, the momentum spectrum becomes quantized. Two electrons can occupy each k-state, one for spin up, one for spin down. Considering an empty metal, we can insert electrons one by one. They will find their lowest energy by packing into a sphere in k-space. Electrons inside the sphere have no states to scatter into, and there are no electrons occupying states outside the sphere. This means that only electrons on the surface of this sphere participate in conduction. The radius of this sphere is called the Fermi wavevector, and converting to units of velocity you get the Fermi velocity. All electrons participating in conduction travel at approximately the fermi velocity... at room temperature plus or minus a tiny fraction of a percent.
- DoingIsLearning 4y ago> So in theory anything done with electricity could be replicated using other waves I sort of get this in a discrete digital logic scenario but out of curiosity as someone not big on Photonics, what would be the light 'equivalent' of an electrical AC signal? I'm kind of struggling to visual that.
- 323 4y ago> It employs two-dimensional quasiparticles called anyons, whose world lines pass around one another to form braids in a three-dimensional spacetime (i.e., one temporal plus two spatial dimensions). These braids form the logic gates that make up the computer. The advantage of a quantum computer based on quantum braids over using trapped quantum particles is that the former is much more stable. https://en.wikipedia.org/wiki/Topological_quantum_computer https://en.wikipedia.org/wiki/Topological_quantum_computer
- huachimingo 4y agoIts like procedural generation: hide the data into a formula/algorithm, so it makes less space. Replace "data" with "computation", and "formula" with physical, less expensive processes.
- deleted 4y ago[deleted]