Is Quantum Mechanics Scale Invariant?

In summary, the conversation revolves around the effects of the scale factor of cosmological expansion on quantum foam and virtual particle production rates. While the quantum foam itself is scale invariant, the rates for virtual particle production may vary depending on the comoving time in cosmology. This is due to the fact that the vacuum state of a field is defined as the lowest energy eigenstate of the Hamiltonian, which is an explicit function of time in an expanding space. One possible solution to this problem is to define the lowest energy eigenstate of the instantaneous Hamiltonian. This suggests that pair production is not constant and may be related to the expansion of the universe. This leads to the question of whether particles are extended objects that cannot be scale invariant. However,
  • #1
Mike2
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I'm wondering what happens if the scale factor of cosmological expansion increases without limit? Will you always calculate the same quantum foam and virtual particle production rates no matter what the scale is of the universe's expansion? If particles are extended objects, then of course virtual particle pair production is effected by the stretching of space. But if particles are singularities, then space may always have the same quantum foam properties no matter how much space is stretched by cosmic expansion. What do you think?
 
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  • #2
Hi,

I think that the quantum foam properties are self-regenerative.

That is to say, as the universe expands the sub-quantal volumes are replaced by new sub-quantal volumes with the same properties as the original.

However, it is possible that the new sub-quantal volumes so created have different properties, and such a situation would mean that the universe is constantly evolving and that over time some of it's macro-properties will become subject to change. The time frame here would relate to just how fast the universe is expanding and how many levels the new sub-quantal volumes would have to pass through before macro-properties are affected.

juju
 
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  • #3
juju said:
Hi,

I think that the quantum foam properties are self-regenerative.

That is to say, as the universe expands the sub-quantal volumes are replaced by new sub-quantal volumes with the same properties as the original.

However, it is possible that the new sub-quantal volumes so created have different properties, and such a situation would mean that the universe is constantly evolving and that over time some of it's macro-properties will become subject to change. The time frame here would relate to just how fast the universe is expanding and how many levels the new sub-quantal volumes would have to pass through before macro-properties are affected.

juju
Or is the quantum foam itself the mechanism by which space expands? If particles are extended objects, then perhaps space is pushed aside as a virtual particle is created. Then only those virtual particles that do not recombine would be responsible for the expansion of the universe. That would at least link the expansion rate with the cosmological constant, right? But if particles are extended objects, then the quantum foam cannot be scale invariant,right?
 
  • #4
what do you by scale factor of the cosmological expansion
 
  • #5
I think this is a question that we cannot answer yet because this involves Quantum Gravity. But speculation is always fun! :smile:
 
  • #6
Divij Desai said:
what do you by scale factor of the cosmological expansion

I don't know much about the subject but we can know the scale behaviour of the Schroedinger equation for example :

starting from space scaling:

x->ax implies t->t*a^2, V->V*a^2

With that scaling law, all the Schroedinger physics is invariant...but for other equations, the scaling is different...was that the question ?
 
  • #7
Hi Mike,

The quantum foam itself is scale invariant since it only exists at the smallest sub-quantum levels.

Imagine that the foam arises from an infinite potential at various symmetric points in the universe. It is only indeterminate foam until it reaches the Planck level where it becomes a determinate potential.

juju

juju
 
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  • #8
juju said:
Hi Mike,

The quantum foam itself is scale invariant since it only exists at the smallest sub-quantum levels.

Imagine that the foam arises from an infinite potential at various symmetric points in the universe. It is only indeterminate foam until it reaches the Planck level where it becomes a determinate potential.

juju

juju
Let's see. If it were possible for the uncertainty principle to allow an infinite energy for the briefest of time, then the existence of infinities would seem to indicate singularities which would not vary with scale factor. But I hear that QED and such has an "ultraviolet cutoff" so that we don't consider pair production higher than a particular level. Did I get that wrong? Thanks.
 
  • #9
Mike2 said:
I'm wondering what happens if the scale factor of cosmological expansion increases without limit? Will you always calculate the same quantum foam and virtual particle production rates no matter what the scale is of the universe's expansion? If particles are extended objects, then of course virtual particle pair production is effected by the stretching of space. But if particles are singularities, then space may always have the same quantum foam properties no matter how much space is stretched by cosmic expansion. What do you think?
As far as I know the rates for virtual particle production are not the same (i.e. the vacuum is not the same) viewed from different comoving times in cosmology. This is due to the fact that the vacuum state of a field is defined to be the the lowest energy eigenstate of the Hamiltonian. However, in case of an expanding space, the Hamiltonian is an explicit function of time and does not have time-independent eigenstates that could be chosen as ‘the vacuum’. One possible solution to this problem (which does not always work) is to define the lowest energy eigenstate of the instantaneous Hamiltonian. This different instantaneous vacua lead to particle production.
 
  • #10
hellfire said:
As far as I know the rates for virtual particle production are not the same (i.e. the vacuum is not the same) viewed from different comoving times in cosmology. This is due to the fact that the vacuum state of a field is defined to be the the lowest energy eigenstate of the Hamiltonian. However, in case of an expanding space, the Hamiltonian is an explicit function of time and does not have time-independent eigenstates that could be chosen as ‘the vacuum’. One possible solution to this problem (which does not always work) is to define the lowest energy eigenstate of the instantaneous Hamiltonian. This different instantaneous vacua lead to particle production.
Let's see, if pair production is related to ZPE which is related to the cosmological constant which is related to universal expansion, then since expansion is not constant, then ZPE and therefore pair production is not constant. It would seem that pair production is related to expansion so that a Conformal invariance, that is, scale invariance in not in effect. Does this prove that particles are extended objects which cannot be scale invariant? Thanks.
 
  • #11
EVERYTHING in the Universe IS EXPANDING!
this includes YOU, the distances in atoms, molecules, and the Planck distance!
the equations of Physics are independent of scale guage.
for example, if all your meter sticks were marked off only in even numbers; SO WHAT?!
love and peace,
and,
peace and love,
(kirk) kirk gregory czuhai
 
  • #12
And this expansion of the Universe is now Accelerating!
love and peace,
and,
peace and love,
(kirk) kirk gregory czuhai
 
  • #13
i should add that these expansions are a lot of times "overruled" "temporaily" by other attractive forces such as gravitation or nuclear or electric charge.
peace and love,
and,
love and peace,
(kirk) kirk gregory czuhai
 

1. What is scale invariance in quantum mechanics?

Scale invariance in quantum mechanics is the property that the laws of physics remain unchanged when the scale of the system is altered. This means that the behavior of particles and systems at different size scales follows the same rules and equations.

2. How does scale invariance affect the behavior of particles?

Scale invariance allows for the prediction and understanding of the behavior of particles at different size scales. This means that the same laws and equations can be used to describe the behavior of particles at the microscopic level, such as atoms and subatomic particles, as well as at the macroscopic level, such as planets and galaxies.

3. Is quantum mechanics truly scale invariant?

There is still ongoing research and debate about the extent to which quantum mechanics is scale invariant. While many theories and experiments have shown evidence of scale invariance, there are also cases where it appears to break down, such as in certain extreme conditions like black holes.

4. How does scale invariance relate to the concept of symmetry in quantum mechanics?

Scale invariance is a type of symmetry in quantum mechanics. Symmetry refers to the invariance of physical laws and equations under certain transformations, such as changes in scale, time, or position. Scale invariance specifically refers to the invariance of laws and equations under changes in scale.

5. What are the implications of scale invariance in quantum mechanics?

The concept of scale invariance has important implications for understanding the fundamental laws and behavior of the universe. It allows for the prediction and explanation of phenomena at all size scales, and has led to significant advancements in fields such as particle physics and cosmology. It also raises questions about the ultimate nature of reality and the relationship between different scales in the universe.

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