Does the Uncertainty Principle imply a linear cosmology?

Click For Summary

Discussion Overview

The discussion revolves around the implications of the Uncertainty Principle in the context of cosmology, specifically whether it can lead to a linear cosmological model. Participants explore the relationship between the uncertainty in the age of the Universe and energy fluctuations, as well as the application of the Uncertainty Principle to the Universe as a whole.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant proposes that the uncertainty in the age of the Universe leads to an uncertainty in energy, suggesting a linear cosmology model based on the Uncertainty Principle.
  • Another participant expresses skepticism, indicating that the application of the Uncertainty Principle may be outside its relevant domain.
  • A third participant argues against the applicability of the Uncertainty Principle to the Universe as a whole, stating that external measurements cannot be made and challenging the existence of an "energy-time" uncertainty principle in this context.
  • A fourth participant adds to the critique by stating that the concept of "energy fluctuations" in the Universe is also incorrect.

Areas of Agreement / Disagreement

Participants generally disagree on the application of the Uncertainty Principle to cosmology, with multiple competing views regarding its relevance and the validity of the proposed linear cosmology model.

Contextual Notes

Participants highlight limitations in the assumptions made regarding the Uncertainty Principle and its application to the Universe, noting the challenges in making external measurements and the definition of energy fluctuations.

jcap
Messages
166
Reaction score
12
If the uncertainty in the age of the Universe is ##\Delta t## then the Uncertainty Principle implies that it has an uncertainty in its energy ##\Delta E## given by
$$\Delta E \ \Delta t \sim h.\tag{1}$$
If this energy fluctuation excites the zero-point electromagnetic field of the vacuum then a photon is created with energy ##\Delta E## and wavelength ##\lambda## given by
$$\Delta E \sim h \frac{c}{\lambda}.\tag{2}$$
Combining Equations ##(1)## and ##(2)## we find that
$$\lambda \sim c\ \Delta t.\tag{3}$$
Now as this characteristic length ##\lambda## is the wavelength of a photon it is a proper length that expands with the Universal scale factor ##a(t)## so that
$$\lambda \sim a(t).\tag{4}$$
Combining Equations ##(3)## and ##(4)##, and taking ##\Delta t \sim t##, we arrive at a unique linear cosmology with the normalized scale factor ##a## given by
$$a(t) = \frac{t}{t_0}.$$
where ##t_0## is the current age of the Universe.
 
Last edited:
Space news on Phys.org
I'll leave it to more knowledgeable folks to weight in, but what I think is that you have extrapolated the HUP to WAY outside of it's domain of relevance.
 
jcap said:
If the uncertainty in the age of the Universe is ##\Delta t## then the Uncertainty Principle implies that it has an uncertainty in its energy

You can't apply the uncertainty principle to the universe as a whole since there is no way to make an external measurement on it, and the uncertainty principle applies to external measurements.

Also, there is no "energy-time" uncertainty principle as you are using it. See, for example, here:

http://math.ucr.edu/home/baez/uncertainty.html

So your post is based on at least two incorrect premises.
 
jcap said:
If this energy fluctuation excites the zero-point electromagnetic field of the vacuum

Correction, three incorrect premises. The universe as a whole doesn't have "energy fluctuations" in this sense.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K