# Can quantum spin be converted to macro systems?

I'm designing an FTL system for a new universe, and I'm trying to figure how 'plausible-sounding' this thought is.

The idea is that space is tangled and twisted in twelve dimensions, so that distant points of three-dimensional space are connected in twelve-dimensional knots, and passing from one part of space to another requires multi-dimensional rotation. Think of it like a set of points on a railway line - the line itself is effectively one-dimensional, but by rotating a train through a second dimension you can switch to a different track.

Our macro universe being, as it is, three dimensional, we have no way to push against these extra dimensions in order to initiate the rotation. This, perhaps, is where quantum mechanics comes in.

Suppose that we are able to control the spin of subatomic particles with extreme precision in twelve dimensions. We spin up a block of "quantum flywheels" in the direction we want turn.

Can that spin then be transferred (albeit at VASTLY reduced speed, of course) to the entire ship, allowing it to rotate through those extra dimensions?

• You might find parts of this interesting. – JDługosz Mar 1 '17 at 22:36
• As I indicate there, if other (large) space dimensions exist you can cause a rotation into them using effects such as precession and it would have effects that show up in 3D. – JDługosz Mar 2 '17 at 6:37

Have you ever heard of the Einstein-de Haas effect?

Take a large piece of iron, cylindrically shaped. Now, put it in an external magnetic field. The bar should become magnetized. Given that magnetization arises from the orientation of electron spins inside the bar, there's a change of spin angular momentum. However, spin angular momentum is just another form of angular momentum, and angular momentum must be conserved. Therefore, the bar will begin to rotate a small bit, to keep the total change in angular momentum zero.

Whether you could do this on a large enough scale is something else entirely. However, using a very, very large magnetic field and the right object, under optimal conditions, perhaps you could have a shot at doing what you want.

There will, of course, be problems:

• You would need to have a very large piece of metal to be magnetized.
• You would have to protect the rest of the ship from the magnetic field.
• The rotating system wouldn't exactly be very portable.
• The entire process could expend a lot of energy.
• I do so love it when I read an answer and exclaim "that's just bull----," only to realize they've linked a Wikipedia article that explains the principle. I learn more things that way! – Cort Ammon Mar 1 '17 at 18:57
• @CortAmmon I know; it's cool. I think the Wikipedia article could use some better editing in a few spots, but it does get the point across. – HDE 226868 Mar 1 '17 at 19:24
• Cool answer! As you mention, there is the risk that it would require too much energy or, for whatever reason, be too difficult to implement on a ship - in such case I guess it ought to be possible to build ship sized stargates in each system one jumps to, which can give some nice plot devices where an outgoing ship can't jump back before the gate in the new system is completed. Altough, that would be all up to OP; I find it fully plausible to have it ship sized. – Mrkvička Mar 1 '17 at 19:38
• @Mrkvička Yes, it's going to strongly depends on the characteristics of the ship (mass, moment of inertia, the properties of the magnet, etc.). That's always good; it means that there's plenty of room to play around. I find that worlds like that are sometimes more successful, especially if small details can be quietly handwaved away or brushed into a corner. – HDE 226868 Mar 1 '17 at 19:40