Based on Tononi's earlier work on Integrated Information Theory, apparently, Maguire et al. have come up with a formulation of consciousness as a lossless integration of information that requires noncomputable functions, which implies that consciousness cannot be modeled computationally.
http://www.newscientist.com/article/dn25560-sentient-robots-not-possible-if-you-do-the-maths.html
I'm personally skeptical of this, but their paper (seen here: http://arxiv.org/abs/1405.0126v1) has some impressive looking formal mathematical proofs that I will admit I lack the mathematical competence to judge the veracity of. Anyone with greater mathematical acumen want to take a look?
None of the words in that paper's abstract mean what they conventionally mean, nor do they mean what they sound like they mean, nor do they mean things that are useful. This is an esoteric point about math, couched in words that falsely resemble philosophy of mind.
The paper does not use the word "sentient" anywhere. That was added by New Scientist.