Bullshit on some of these. Either the people haven’t thought at all about the ideas they propoe or, more likely, the writer of the article screwed up. Why would you need a solar sail with antimatter? It’s useless. A regular rocket engine style contraption would do the same thing much smaller.
You might be able to find the answer by digging through the abstract which can be found here.
Tuckerfan, thanks for the link, but the abstracts are just that. Anything the writer got about a solar sail must have either come from discussion with the researchers or his own head.