Is matter the most efficient storage of energy?

I was thinking about the Star Trek replicators the other day and realized that if they simply create the matter from stored energy than they must still have to be carting around X kilos of matter+anti-matter for the generators if they are to make X kilos of Saurian brandy.

Is there, even theoretically, a more compact and efficient way to store and or create energy than a matter anti-matter mix?

You could get (theorically or at least on a Star Trek fiction universe) energy from nowhere, harness the vacuum energy around and within us.

You could, in principle, pack as many photons as you liked in an area (make sure that the walls of your container are perfectly reflective, or you’ll lose some). At least, up the the density which would result in them turning into a black hole. But then, one might question whether a black hole counts as “matter”: For any given amount of energy, a black hole will be the smallest way to contain it (or alternately, for any given volume, a black hole contains the most energy).

But for practical purposes, and excluding black holes, matter is the best.

I prefer anti-matter. It’s got all the energy content of regular matter, but in a convenient pop top can. :wink:

What are the other options?

A field?