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jgraber
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Strings vs. Loops--Black Hole Metrics?
You read a lot about how strings and loops can both derive the Bekenstein-Hawking entropy formula for black holes. String calculations only work for near extremal black holes, but they get the Immirzi-Barbero parameter right. Loop calculations work for all black holes, but need extra work to get the Immirzi Barbero parameter right. Something like that, anyway. Also, it seems that Strings require a dilaton, which leads to scalar-tensor gravity with a Brans-Dicke type metric. Also, you hear a lot about Gauss- Bonnet gravity, especially in connection with brane-worlds. There’s also a BTZ black hole or something like that, too. And of course, string black holes come in all sorts of weird dimensions all the way from 1+1 to 1+9. But I don’t get the bottom line.
For someone who understands metrics but not strings or loops, what is the difference between an old fashioned Kerr or Schwarzschild black hole and a stringy one or a loop one?
In particular, what black hole metric or metrics does String theory lead to? LQG? Are they the same or different?
References are good. TIA for any help. Jim Graber
You read a lot about how strings and loops can both derive the Bekenstein-Hawking entropy formula for black holes. String calculations only work for near extremal black holes, but they get the Immirzi-Barbero parameter right. Loop calculations work for all black holes, but need extra work to get the Immirzi Barbero parameter right. Something like that, anyway. Also, it seems that Strings require a dilaton, which leads to scalar-tensor gravity with a Brans-Dicke type metric. Also, you hear a lot about Gauss- Bonnet gravity, especially in connection with brane-worlds. There’s also a BTZ black hole or something like that, too. And of course, string black holes come in all sorts of weird dimensions all the way from 1+1 to 1+9. But I don’t get the bottom line.
For someone who understands metrics but not strings or loops, what is the difference between an old fashioned Kerr or Schwarzschild black hole and a stringy one or a loop one?
In particular, what black hole metric or metrics does String theory lead to? LQG? Are they the same or different?
References are good. TIA for any help. Jim Graber