5 ms·
> When it comes to information transfer and processing, light can do things that electricity can’t. Photons — particles of light — are far zippier than electron
by nabakin 5mo ago
> When it comes to information transfer and processing, light can do things that electricity can’t. Photons — particles of light — are far zippier than electrons at working their way through circuits.
Electrons themselves don't move at the speed of light, but information transfer (i.e. communication) via electrons does happen close to the speed of light.
A subtle, but important, distinction that's often misunderstood and means computational performance gains would probably come from bandwidth, not latency.
- NL807 5mo agoIn electric circuits, information is transmitted through the electric field, which itself is close to the speed of light.
- tempaccount5050 5mo agoNope, it's 1/2 - 2/3 the speed of light depending on the metals used.
- spwa4 5mo agoYou're both wrong. It's true that the first whisper of movement travels at the speed of light, but the time until the flow stabilizes (which you WILL need to wait for in electrical chips) is actually slower than the "speed of electricity". Oh and also: currently the idea behind on-chip lasers is interconnects that don't have this limitation. For example, PCIE is looking to build optical interconnects, which will do the equivalent of bringing every GPU 10x closer to the memory. Optical computation would require that light switches light transistors on and off, which doesn't seem to be possible with this technology. This is optical computation in the sense of allowing light beams to be produced according to formulas.
- BenjiWiebe 5mo agoWhy do you need to wait for it to stabilize? You can keep changing the voltage at one end of the connection even if you have megabits of data currently in transit, without waiting for it to stabilize. Yes, you'll need to do impedance matching. Yes, that's a solved problem. Transmission lines.
- KK7NIL 5mo agoThe velocity factor is usually 0.6-0.7, never seen it as low as 0.5. And it's set by the dielectric, not the conducting material.
- Hikikomori 5mo agoAbout 0.6c for cat6 cables, different types of cables can be slightly faster. Speed of light in fiber is also 0.6c due to the refractive index of the core.
- derefr 5mo agoIs that through solid-core fiber? Because hollow-core fiber also exists.
- Hikikomori 5mo agoYes. It does, but it's not widely used, it barely just got out of the lab.
- thayne 5mo ago> but information transfer (i.e. communication) via electrons does happen close to the speed of light Speed of light in the medium, not speed of light in vacuum.
- sbuttgereit 5mo agoLooking at the discussion below this comment, I'd just add this video by AlphaPheonix: https://www.youtube.com/watch?v=2Vrhk5OjBP8 https://www.youtube.com/watch?v=2Vrhk5OjBP8 Good discussion in the comments there as well.