Is there any way to concentrate the magnetic field of magnets like a bar magnet at a point?
Permeable (ferrous/ ferromagnetic) materials can guide magnetic flux to a point, but magnetism works better with area. The only way I can think of "concentrating" magnetic flux is to create a coil of wire with electricity flowing through it. Permanent magnets have a set flux strength. They will never get stronger (by themselves), but they could lose flux strength over time and under certain conditions.
No, if you had a universe with just one magnet in it, there would always be a magnetic field at every point in space no matter what you did.
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