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## Main Question or Discussion Point

here is a fairly simple question... is the purpose of quantum gravity to relate gravitation/relativity to our understanding of quantum machanics as is? im not entirely sure on this, could someone explain

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here is a fairly simple question... is the purpose of quantum gravity to relate gravitation/relativity to our understanding of quantum machanics as is? im not entirely sure on this, could someone explain

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and yes i know it has only been theorized.....

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professor said:here is a fairly simple question... is the purpose of quantum gravity to relate gravitation/relativity to our understanding of quantum machanics as is? im not entirely sure on this, could someone explain

The various quantum gravity programs are aimed at a consistent method of quantizing gravity that reduces to general relativity in the h -> 0 limit. Techniques of quantization used are the ones that have been developed for other quantum theories, especially quantum field theory.

Whether this quantization, if it is achieved will support "quantum mechanics as it is", by which I suppose you mean the Standard Model of particle physics, will be a matter of experiment. A theory of quantum gravity that wound up flatly denying what theory and experiment have shown us would be regarded as a failure.

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The purpose of quantum gravity is to create a unified and consistent theory that reconciles quantum mechanics with general relativity, i.e., explains all the phenomena of both theories, and perhaps to predict new phenomena.professor said:

The most obvious obstacle is that quantum mechanics has been developed on a background of Newtonian space and time, i.e., flat space-time without curvature, while general relativity views gravitation not as a force, but as curvature of space-time induced by mass. One approach that has been taken is to modify quantum mechanics to work with curved space-time. An alternative approach is to construct a theory of gravity largely equivalent to GR but in flat space-time and then to integrate the two theories. Both approaches have been used by eminent physicists. I believe, but am not sure, that a more serious problem is how to handle renormalization in the combined theories. (In quantum field theory, many divergent series arise, whose values are computed using a variety of rules of thumb for ordering terms. This "dippy" process, as Feynman called it, is "renormalization".)

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perfect...exaxtly what i was looking for