- #1
soothsayer
- 423
- 5
"Quantum" gravity -- Planck's constant as a scalar field?
I was just reading about a fascinating new theory on the solution to the quantum gravity problem:
http://arxiv.org/pdf/1212.0454.pdf
I really like it, but I have one big problem with it:
The author states that
[itex]G = \frac{\hbar c}{m_{Pl}^2}[/itex]
where [itex]m_{Pl}^2[/itex] is the Planck mass, and says that gravity can then be considered to be coupled to Planck's constant. But my issue is: if [itex]m_{Pl}^2[/itex] is defined to be [itex]\hbar c/ G[/itex], then isn't this an empty statement? Specifically, the author goes on to say that Planck's constant could in fact be a scalar field, and the observed nonzero value of the Planck constant could be due to symmetry breaking after the big bang, much like in the Higgs mechanism. When defining Newton's gravitational constant, the author casually mentions that the Planck mass is constant, but how can that be true if it is tied to the Planck constant, which the author says is not actually a constant? Does the author mean that the Planck mass is equal to [itex]\hbar_0 c/G[/itex] where [itex]\hbar_0[/itex] is the current, experimental value of Planck's constant (The ground state of the field)? Is that valid?
Just wanted to get PF's thoughts on it. Thanks!
I was just reading about a fascinating new theory on the solution to the quantum gravity problem:
http://arxiv.org/pdf/1212.0454.pdf
I really like it, but I have one big problem with it:
The author states that
[itex]G = \frac{\hbar c}{m_{Pl}^2}[/itex]
where [itex]m_{Pl}^2[/itex] is the Planck mass, and says that gravity can then be considered to be coupled to Planck's constant. But my issue is: if [itex]m_{Pl}^2[/itex] is defined to be [itex]\hbar c/ G[/itex], then isn't this an empty statement? Specifically, the author goes on to say that Planck's constant could in fact be a scalar field, and the observed nonzero value of the Planck constant could be due to symmetry breaking after the big bang, much like in the Higgs mechanism. When defining Newton's gravitational constant, the author casually mentions that the Planck mass is constant, but how can that be true if it is tied to the Planck constant, which the author says is not actually a constant? Does the author mean that the Planck mass is equal to [itex]\hbar_0 c/G[/itex] where [itex]\hbar_0[/itex] is the current, experimental value of Planck's constant (The ground state of the field)? Is that valid?
Just wanted to get PF's thoughts on it. Thanks!