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Is it possible to create periodic potentials that instead of creating a well for an atom to be trapped in, repulsed by that specific location?

If yes, can we use this as a means to make artificial objects that we can feel, with let's say our hands, by putting lots of these repulsive points together?

This is an idea that I have in order to make holograms that we can feel like the holodeck in Star Trek.

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...It's a periodic potential. The atoms are repelled from the peaks and fall into the valleys.. what is it that you to be different? Also if you want of holodecks I think you will find the forces involved in this sort of physics to be rather underwhelming. – BebopButUnsteady Aug 5 '11 at 0:18
up vote 1 down vote accepted

Atoms in an optical lattice are attracted to high/low field states depending on the quantum state the atom is in. Atoms in states that would be shifted down in energy by the application of an electric field are drawn to low-field regions and repulsed from high-field regions, and vice versa for atoms in states that would be shifted up in energy by the application of an electric field.

The answer to part 1 is that this is possible, and in fact atoms are already "repulsed" by parts of the lattice anyway. Which part of the lattice is attractive/repulsive depends on the state the atom is in.

Because optical lattices are by definition periodic, these "repulsive" regions are surrounded by attractive regions, and the atoms in you hand tend to migrate from the repulsive to the attractive regions. I don't think you'd be able to make a macroscopic force you could feel with your hand.

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what is the physical meaning of "trap"? Does only potential well trap particles? – Timothy Sep 6 '13 at 16:02
@Jeremy: You usually have to cool (slow) the atoms down to be able to trap them. For an explanation of how this is done, see here – Dan Sep 6 '13 at 17:48

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