Hello PF community! While reciently reading another thread this paper was posted as a link: http://arxiv.org/ftp/cond-mat/papers/0602/0602591.pdf now about 5 pages in it stated that the authors found a wave length and mass for a graviton???? I did not even know they were proven to be real. I saw that the initial number was complex and almost did not post my questions but a bit later on I saw that they converted it into a real number! I am just asking how that is possible and how long has it been known that gravitons actually do happen? Fyi: I have a basic understanding of calc and below so I realize I can not fully understand the paper or most of the physics for that matter, so please help me out here. Thank you in advance. Also I am typing this on an iPhone so I am sorry for any mistakes in spelling or word choice here. Thanks again!!