The physics of Peter F. Hamilton's Nova Bombs?

[Fanghur]

I recently finished reading Peter F. Hamilton's Commonwealth Saga (which I highly recommend to any Sci-Fi fans out there), and usually he's pretty good at incorporating actual scientific concepts into his stories when the plot doesn't require him to invent various Clarke-techs, but I was hoping someone with the know-how might be able to answer something. 

One of the technologies that humanity develops in the series is something they call a nova bomb, which is fired into a star to cause it to go nova. But the explanation given for exactly how it works is that once it gets deep into the star it emits some kind of quantum field that causes, quote, 'A volume of the star's interior the size of a super-Jovian gas giant to be converted directly into energy'. Now clearly this is an entirely fictional technology, but does anyone know how something like that would compare to an ACTUAL supernova assuming for the sake of argument that is possible? I don't know how to work out the math, but from what I do know about it, I would think that the actual effect the nova bomb would have would make an actual supernova look like a firecracker by comparison.

[MigL]

IIRC a ( super )nova actually converts gravitational potential into energy.
When the core of the star has a high iron content and ceases fusion, gravity forces its outer layers to collapse as there is no more radiation pressure to support them.
At some point these outer layers, which are still rich in light elements, reach pressures which will support fusion again, ignite, and blow away some of the outer layers in a violent release of energy.

You can see the blown away'' gases/dust around around old nova, such as the  Crab nebula, which has a rapidly spinning neutron star ( pulsar ) at its center, and was recorded by Chinese astronomers in 1054.

As to the OP...
An amount of anti-matter much, much smaller than a Jovian gas giant would do the trick.
But you'd need to be able to deliver it to the center of the star.

[Janus]

If we assume a volume that has a radius twice that of Jupiter, and a stellar core density equivalent to our Sun's,  then we are talking about an energy release of 2e46 joules of energy from the total conversion. A supernova may release 1e44 joules of energy. 

[Fanghur]

So then the firecracker comparison was a bit of an exaggeration, but not by much. Either way, I guess Hamilton didn't bother doing the math.