Hubble constant

  • #1
1. Homework Statement
If [tex]\phi[/tex] is a usual field is it possible that
[tex]H\dot{\phi}=-\partial^2\phi/{\partial x^2}[/tex]
Where H is the hubble constant and the dot denotes time derivative




2. Homework Equations
[tex]H\dot{\phi}=-\partial^2\phi/{\partial x^2}[/tex]




3. The Attempt at a Solution
I tried different ways but am not able to find the particular expression for hubble constant used here.
 
Last edited:

Answers and Replies

  • #2
fzero
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On a curved spacetime, the Klein-Gordon equation for a massless scalar field is ##\nabla^\mu \nabla_\mu \phi =0##. If the spacetime is of the FRW type, then there will be a term proportional to ##H\dot{\phi}##. You seem to have missed the ##\ddot{\phi}## term in your expression, so you might want to go through the exercise of working this out from first principles.
 
  • #3
On a curved spacetime, the Klein-Gordon equation for a massless scalar field is ##\nabla^\mu \nabla_\mu \phi =0##. If the spacetime is of the FRW type, then there will be a term proportional to ##H\dot{\phi}##. You seem to have missed the ##\ddot{\phi}## term in your expression, so you might want to go through the exercise of working this out from first principles.
Thanks a lot. I did miss that term because this was the part i was confused about but i guess that was important too.
 

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