Bosons are either gapped or condensated, except physical principle protected cases (Goldstone boson, photon, etc.). I read this in a paper (version1 of http://arxiv.org/abs/1404.3728v1, 1st page 1st column) and other lecture slides (page 6 of http://discor2013.files.wordpress.com/2013/12/lee.pdf).

It's not really pertinent to the mainstream of that paper. But it sounds rather intriguing and necessary to be further clarified. So could anyone make it clearer? Thanks!

Bosons are either gapped or condensated, except physical principle protected cases (Goldstone boson, photon, etc.). I read this in a paper (version1 of http://arxiv.org/abs/1404.3728v1, 1st page 1st column) and in other lecture slides (page 6 of http://discor2013.files.wordpress.com/2013/12/lee.pdf). This slide appears to talk about some mean field result of spin liquid state.

This statement is not really pertinent to the mainstream of that paper. But it sounds rather intriguing and necessary to be further clarified. So could anyone make it clearer? Thanks!