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Thank you. ^^

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- Thread starter Eolill
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In summary, string theory tackles the issue of infinite gravitation in the combination of quantum mechanics and general relativity by avoiding the use of perturbation series. It does this through topological constraints on the string world sheet, which are believed to remove the infinities that arise in perturbatively quantized GR. Additionally, string theory predicts the existence of a massless spin-2 particle, the graviton, which is one of its main appeals.

- #1

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Thank you. ^^

- #2

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Due to some properties of GR one can show that the individual terms in this series become infinite. That's uggly, but not the core of the problem. These infinities are wel-known from QFT, but there they can be removed via renormalization. One can show that this FAILS in perturbatively quantized GR.

In s.t. one expects that due to the topologically constraints for the string world sheet those infinities do not show up. As far as I know no proof to all orders exist but the s.t. community agrees that it will show up eventually.

What I don't expect is that the perturbation series as a whole (the sum) is finite. I would say that this is not due to a failure in the fundamental theory but due to the perturbation expansion. This tool is overestimated because of its successes in particle physics. In a fundamental theory with non-perturbative treatment no infinities should arise; this should be true in s.t. and it is true in other QG approaches.

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