Is there something else, other than an electron, that can be used as energy?

Electrons are the smallest and most mobile subatomic particles. The only alternatives I can think of are magnetic fields, which have a range of a few metres, and intense laser light, which is expensive and inefficient.

Smaller electrical circuits also produce more heat than large ones, because the same current passes through the same volume of wire/transistor.

@FireMadeFlesh How about neutrino’s they’are smaller than electrons all we need is to find a way to record a 1 and a 0 and boom… were in business… do Sub-Sub-Atomic particles exist?

@talljasperman Neutrinos have no charge, have a mass so small we cannot measure it, and the only known way they can interact with matter is by the extremely improbable direct impact with an atomic nucleus which then releases radio waves. The vast majority of neutrinos travel straight through the Earth without interacting with anything at all.

Sub-sub-atomic particles do exist, they are called quarks and they are the building blocks for all hadrons (protons, neutrons, muons etc). However the principle of confinement means that a quark can never be isolated to travel by itself. The smallest quarks are still much bigger than an electron though, which is why all hadrons are bigger than all leptons.

If your main concern is about loss of energy to heat, then you may find superconductivity an interesting topic to look into. Basically, if you cool a conductor down to its critical temperature, which is usually close to absolute zero, it will conduct without any energy loss for several years. This is the principle behind the magnets in an MRI. The catch is that the conductor needs to be kept below its critical temperature, or it will lose this property.

The sun uses photons to send energy to us.

If you have indoor plumbing, you have another type of energy provided to you, pressurized water. There’s no electricity in most toilets, they’re powered by pressurized water. This jet pack runs on pressurized water:

http://www.youtube.com/watch?v=llPS0qOiMd4

Optical computers are perfectly feasible but don’t benefit much from all the investment already sunk into microelectronics.

Neutrinos’ interaction with normal matter is mediated by the (aptly-named) ‘weak nuclear force’. All the actions of the electromagnetic force are accomplished by virtual photons (which are exchanged between the particles that are interacting) which are mass-less and can travel an arbitrary distance. There are three particles that do this work for the weak nuclear force, the positive and negatively-charged W particles and the neutral Z particle. They are quite heavy, which limits the range the force can act. Also the coupling constant, the chance any moment a neutrino will emit a virtual W or Z, is tiny. By comparison the coupling constants (actually they vary with energy, given here for “low” energies) are strong force = 1, electromagnetic force = 1/137, weak = 1×10^-6, gravity = 1×10^-39 (although gravity’s coupling constant is so tiny, the graviton is mass-less so again the force is long-range, which is why this force is so much more notable than the weak force).

Another strange aspect of the weak-nuclear force is that it is “handed”, i.e. it breaks mirror symmetry. Strangest of all, despite of all this it is a twin of electromagnetism. Raise the temperature to 10^15 K and the two forces unite into the electroweak force.

More than 50 trillion neutrinos from the sun pass through your body each second, and the vast majority of those go on to pass completely through the earth without interacting with it at all (or the other way around, through the earth and then through you, at night!).

I would go for photons. Powers my satellites.

Peltier is another I didn’t see mentioned already. Don’t think it’ll be replacing our grid anytime soon though lol.

Gravity?

@FireMadeFlesh “Smaller electrical circuits also produce more heat than large ones, because the same current passes through the same volume of wire/transistor.” Nope. Smaller semiconductor circuits are built to operate with less current. Notice they have been using smaller and smaller operating voltages in recent years, largely to reduce current to minimal amounts required to function.

@talljasperman “used as energy” is so ambiguous… How do you want to use it?
I like the answers that refer to E-M waves, which includes all the answers with heat or photons…

@dabbler Used in a computer chip… to make smaller faster chips that don’t overheat. Something smaller than an electron might just work.

@talljasperman Hmm, fascinating. Who knows? Seems like a different question from “used as energy” but I’ll bite…
For what we think of currently as ‘computing’ you still need to get some ordinary information into the machine and back out, the interfaces to ordinary user controls/displays are a factor.

There is some interesting work going on with photonic logic that uses light to convey data states. there are crystalline structures with negative indeces of refraction that have been fabricated in R&D labs that can switch a ‘bit’. Those crystaline structures are orders of magnitude larger than an electron though.

Labs have made light-based memory devices that encode beams with information and send them into structures with mirrors that are so perfectly parallel that it takes a while to get from one end to the other and cycle back to the start after reflecting a bajillion times back and forth within it. The same researchers have shown that you can access the data at any point on the surface and get whatever part of the data chain is going by that spot in the moment.

Putting on my sci-fi hat, I could imagine a resonant quark plasma with surfaces that somehow perform interface functions. Quarks are smaller than electrons…