Is Gravitation Necessary for Unification?

[xaratustra]

just came to my mind to ask: Is gravitation really a fundamental force? As far as I recall from my GR lecture, gravitation is a property of space-time. Other forces seem to be well described by the grand unified theories (GUT).

So why is there still a need to include gravitation?

cheers!

 

[mfb]

GUT is an open problem itself.
Apart from that, you cannot simply work with quantum field theory in a curved space. Or at least it is unclear how that could be done.

 

[mathman]

In regimes where general relativity and quantum theory are both needed (inside black holes), they are incompatible.