excuse all the questions, but i've just recently started reading about quantum mechanics and want to know about what quantum physicists currently believe about GR.. How sure are physicists that a graviton exists? Is there such a thing as curved space-time in quantum mechanics, and if so is the curvature quantized? If not is all geometry Euclidean? Is it known from experimental evidence that the general theory of relativity has flaws, or is it just that GR doesn't make sense in the context of QM? If so, could it be that revisions need to be made to QM to make it work with GR or is it necessary that GR is flawed and a graviton must be found? Is it impossible to describe the other forces as curvatures in space-time? Are there any known flaws with SR? I would guess the thing where one particle's spin automatically changes another particle's spin (entanglement?) points out a flaw in SR, but I don't know. If so, is it certain that the problem here is with SR and it's not QM that needs to be fixed on this issue? And can anyone recommend a good popularized book on quantum mechanics with very little math? I'd like to learn the math as well, but first I'd like to be a little familiar with the ideas behind QM. thanks.