[8note]

Superconductors pretty notoriously need to be kept cold, which adds another difficulty of cooling the antimatter without touching it

[whatshisface]

If it was surrounded by a cold mass that it could radiate photons to across a vacuum, its equilibrium temperature would be that of its container.

[kadoban]

For now. By the time anyone could even possibly create enough antimatter to matter (heh), critical temperatures should be much higher. The record is broken fairly commonly.