I posted one quantum theory about this paper: http://www.arxiv.org/abs/quant-ph/0501034 Chen uses a double Kalusza-Klein mod to GR with the two extra dimensions being timelike. He claims this introduces QM into the modified GR, so he has interacting QM and gravity, then he claims to support Dirac spinors in his formalism. These are bold claims and he shows his work. I wonder if that work is correct and don't myself have the chops to say yea or nay. Would some of you gurus just take a look? Thanks.