Quantum Fluctuations/Foam

[interested]

I am seeking some clarification ref quantum fluctuations in space. What could they caused by? 

The quantum effects are probabilistic, not deterministic. Therefore, a quantum fluctuation has no "cause." Quantum fluctuations are a point change in the energy of a volume of space due to the Heisenberg Uncertainty Principle.

Can they be viewed as a result of interference waves moving at light speed in various directions, (similar to the double slit experiment), creating an apparent probabilistic and not deterministic effect. If they are viewed in this way they have a cause but it is not possible to calculate there appearance other than via probability theory.

https://en.wikipedia.org/wiki/Quantum_fluctuation

 

[Strange]

10 minutes ago, interested said:

What could they caused by?

They are a consequence of the uncertainty principle. As the link explains. (I was going to try and explain it, but then realised I would just be repeating what was one that page.)

15 minutes ago, interested said:

Can they be viewed as a result of interference waves moving at light speed in various directions

No.

[interested]

19 hours ago, Strange said:

They are a consequence of the uncertainty principle. As the link explains. (I was going to try and explain it, but then realised I would just be repeating what was one that page.)

No.

Wave functions can also describe quantum fluctuations, I found a paper on it, it also explains entanglement in terms of wave functions.

https://arxiv.org/ftp/arxiv/papers/1402/1402.4764.pdf Reality of the wave function

https://en.wikipedia.org/wiki/Wave_function

Whilst Heisenburgs uncertainty principle gives answers. Waves give a plausible explanation as to why there is quantum fluctuations filling all of space.

 

Edited April 22, 2018 by interested

[Strange]

2 hours ago, interested said:

Wave functions can also describe quantum fluctuations, I found a paper on it, it also explains entanglement in terms of wave functions.

https://arxiv.org/ftp/arxiv/papers/1402/1402.4764.pdf Reality of the wave function

 

The uncertainty principle is (or can be considered as) a consequence of the fact that quantum effects can be described as waves.

That paper appears to be claiming that the wave function of a particle (e.g. an electron) can be considered to arise as a result of quantum fluctuations. Kind of the opposite of what you said.

However, as the non-zero energy if the vacuum and associated quantum fluctuations are a consequence of the fact that fields (and the associated wave functions) are quantised, that argument seems to be a bit backwards.

[interested]

On 4/22/2018 at 12:12 PM, Strange said:

The uncertainty principle is (or can be considered as) a consequence of the fact that quantum effects can be described as waves.

That paper appears to be claiming that the wave function of a particle (e.g. an electron) can be considered to arise as a result of quantum fluctuations. Kind of the opposite of what you said.

However, as the non-zero energy if the vacuum and associated quantum fluctuations are a consequence of the fact that fields (and the associated wave functions) are quantised, that argument seems to be a bit backwards.

Is it not a case of the chicken and egg,  quantum fluctuations do not exist without waves  and vice versa. 

[Strange]

2 minutes ago, interested said:

Is it not a case of the chicken and egg,  quantum fluctuations do not exist without waves  and vice versa. 

I would say the wave description comes first, and both the non-zero vacuum energy and uncertainty principle are a consequence of that. But on the other hand, I don't think it makes sense to separate cause and effect in something like this. 

[interested]

On 4/24/2018 at 10:06 AM, Strange said:

I would say the wave description comes first, and both the non-zero vacuum energy and uncertainty principle are a consequence of that. But on the other hand, I don't think it makes sense to separate cause and effect in something like this. 

An after thought from the links posted above can virtual particles combine to form real particles electrons for instance, which according to field theory spend fleeting moments of their lives as virtual particles.

[swansont]

24 minutes ago, interested said:

An after thought from the links posted above can virtual particles combine to form real particles electrons for instance, which according to field theory spend fleeting moments of their lives as virtual particles.

Combine? No. Any fluctuation will be particle/antiparticle pairs.

If you add energy to the virtual particles, they can become real particles.

[interested]

18 hours ago, swansont said:

Combine? No. Any fluctuation will be particle/antiparticle pairs.

If you add energy to the virtual particles, they can become real particles.

How do you add energy to a virtual particle?

Is it possible to compress virtual particles together to form a particleor photon? 

In a smaller  universe would quantum fluctuations in space be more compressed and result in real particles or photons appearing from quantum fluctuations? (kind of BB idea  ) 

[Strange]

14 minutes ago, interested said:

How do you add energy to a virtual particle?

Using a strong electric field, maybe?

Or a laser: https://www.newscientist.com/article/dn19327-lasers-could-make-virtual-particles-real/

I don't know if Unruh radiation can be thought of as being created from the energy that provides the acceleration. Rather like Hawking radiation can be described in terms of the gravitational energy of the black hole separating virtual particle pairs. Although it isn't clear (to me) if that is an accurate analogy or not.

17 minutes ago, interested said:

Is it possible to compress virtual particles together to form a particleor photon?

Well, they would annihilate to create a pair of photons, if that is what you mean.

18 minutes ago, interested said:

In a smaller  universe would quantum fluctuations in space be more compressed and result in real particles or photons appearing from quantum fluctuations?

Surely, being closer together would make them more likely to annihilate one another?

[swansont]

28 minutes ago, interested said:

Is it possible to compress virtual particles together to form a particleor photon? 

In a smaller  universe would quantum fluctuations in space be more compressed and result in real particles or photons appearing from quantum fluctuations? (kind of BB idea  ) 

Quantum fluctuations require energy to be added for you to get a real particle, as I have already stated. No scenario you propose that ignores that requirement is going to work.

[interested]

1 hour ago, Strange said:

Well, they would annihilate to create a pair of photons, if that is what you mean.

Virtual particles pairs are normally entangled. Do they need to appear adjacent to each other, also other virtual particles might appear between virtual particles and move them apart. separated 

1 hour ago, Strange said:

Surely, being closer together would make them more likely to annihilate one another?

I was wondering if a less expanded space( in the extreme case a singularity) might have more intense quantum fluctuations, appearing as a function of a BB for instance. 

1 hour ago, swansont said:

Quantum fluctuations require energy to be added for you to get a real particle, as I have already stated. No scenario you propose that ignores that requirement is going to work.

Accepted,

BUT energy cant be created or destroyed, so where did it come from.? The HUP allows quantum fluctuations  to appear out  of the vacuum of the vastness of space and exist momentarily before disappearing again . I was wondering what would these quantum fluctuations be like at the point of a Big Bang in a more concentrated space, a singularity for instance. Space still has the same amount of energy  as it did at the Big Bang, how did it get it? What are the chances of multiple quantum fluctuations all appearing at the exact same space and time, would they appear as actual particles.  

The energy in the Big Bang must have released more EM radition than any laser ever could. If the EM radition of the BB interacted with virtual particles would  real particles apppear perhaps, as per

1 hour ago, Strange said:

https://www.newscientist.com/article/dn19327-lasers-could-make-virtual-particles-real/

. 

 

[Strange]

7 minutes ago, interested said:

Virtual particles pairs are normally entangled.

Are they? (I don't know. I don't even know if entanglement means anything for virtual particles. But it seems plausible that they would be.)

8 minutes ago, interested said:

Do they need to appear adjacent to each other

I assume so. Although, there will be an uncernatityw in their position, inversely proportional to the uncertainty in momentum.

9 minutes ago, interested said:

I was wondering if a less expanded space( in the extreme case a singularity) might have more intense quantum fluctuations, appearing as a function of a BB for instance.

It is a function of the non-zero energy of the vacuum. I don't know how or if that is related to the density of matter around - I assume not as it is the energy of the vacuum.

10 minutes ago, interested said:

The energy in the Big Bang must have released more EM radition than any laser ever could. If the EM radition of the BB interacted with virtual particles would  real particles apppear perhaps, as per

There is a difference between the energy in a plasma (which is evenly distributed and the same anywhere) and the energy in a laser, which is highly collimated, coherent, single-frequency source. 

And, in all cases, the anti-particle will soon annihilate with a particle to produce two photons. You are not magically creating "new matter" doing this.

[interested]

16 minutes ago, Strange said:

Are they? (I don't know. I don't even know if entanglement means anything for virtual particles. But it seems plausible that they would be.)

I assume so. Although, there will be an uncernatityw in their position, inversely proportional to the uncertainty in momentum.

It is a function of the non-zero energy of the vacuum. I don't know how or if that is related to the density of matter around - I assume not as it is the energy of the vacuum.

There is a difference between the energy in a plasma (which is evenly distributed and the same anywhere) and the energy in a laser, which is highly collimated, coherent, single-frequency source. 

And, in all cases, the anti-particle will soon annihilate with a particle to produce two photons. You are not magically creating "new matter" doing this.

Assuming quantum fluctuations are a result of the underlying field and can be described as field quanta having energy E=hf similar to electrons, positrons etc. Quantum fluctuations appear and disapear all the time, why isnt space full of radition as a result of this apparent continual loss of virtual particles. Could it be that these virtual particles appearing in space  are not produced in pairs, but are just the result of fields or waves interacting with each other  producing an interference effect., with peaks and troughs.

You have mentioned the energy of the vacuum a number of times do you have a link to how it is calculated? 

There is an imbalance of matter antimatter particles in the universe could it be they are not always produced as pairs, which then annihilate each other. 

I am not trying to create matter, I just want to know how it could happen, if virtual particles pairs do not appear next to each other, why would they need to annihilate.

[Strange]

34 minutes ago, interested said:

Assuming quantum fluctuations are a result of the underlying field and can be described as field quanta having energy E=hf similar to electrons, positrons etc.

They can't.

34 minutes ago, interested said:

Quantum fluctuations appear and disapear all the time, why isnt space full of radition as a result of this apparent continual loss of virtual particles.

Because they are virtual (short-lived, transient) particles. Why would space be full of radiation because of them?

35 minutes ago, interested said:

Could it be that these virtual particles appearing in space  are not produced in pairs, but are just the result of fields or waves interacting with each other  producing an interference effect., with peaks and troughs.

The answer hasn't changed.

We have a theory explaining why. So what is the point of trying to make up another one (that ins't based on physics)?

37 minutes ago, interested said:

You have mentioned the energy of the vacuum a number of times do you have a link to how it is calculated? 

https://en.wikipedia.org/wiki/Zero-point_energy

(Do you have short/medium term memory problems? Or am I hallucinating the fact that we have been round this loop half a dozen times, at least. Is this Groundhog Physics?)

37 minutes ago, interested said:

There is an imbalance of matter antimatter particles in the universe could it be they are not always produced as pairs, which then annihilate each other. 

There is (still) no evidence for this.

38 minutes ago, interested said:

I am not trying to create matter, I just want to know how it could happen, if virtual particles pairs do not appear next to each other, why would they need to annihilate.

Because they are virtual particles. They have no real existence except as a temporary fluctuation allowed by the Heisenberg Uncertainty Principle. You can think of them "borrowing" some energy from the vacuum as long as they pay it back almost instantly. The more massive they are, the less time they have the loan for.

[StringJunky]

46 minutes ago, interested said:

Assuming quantum fluctuations are a result of the underlying field and can be described as field quanta having energy...

They are called 'virtual' because they are not quanta, they are less than that. Anything that is less than a quanta has no affect on matter and is not individually measurable.

Edited April 26, 2018 by StringJunky

[swansont]

1 hour ago, interested said:

 BUT energy cant be created or destroyed, so where did it come from.? The HUP allows quantum fluctuations  to appear out  of the vacuum of the vastness of space and exist momentarily before disappearing again .  

The vacuum energy is not zero, according to QM. In addition, the restriction of energy conservation is modified by the HUP. You can't say energy conservation has been violated on short time scales, as long as the uncertainty is consistent with the HUP.

[interested]

17 hours ago, StringJunky said:

They are called 'virtual' because they are not quanta, they are less than that. Anything that is less than a quanta has no affect on matter and is not individually measurable.

The expansion of the universe Dark energy may be driven by quantum fluctuations. The casimir effect is direct measurable evidence of virtual particles/quantum fluctuations. See stranges link above.

[Strange]

5 minutes ago, interested said:

The expansion of the universe Dark energy may be driven by quantum fluctuations. The casimir effect is direct measurable evidence of virtual particles/quantum fluctuations. See stranges link above.

not individually measurable.

[swansont]

19 hours ago, StringJunky said:

They are called 'virtual' because they are not quanta, they are less than that. Anything that is less than a quanta has no affect on matter and is not individually measurable.

As interaction exchange particles are virtual, I would disagree that they have no effect on matter. Quite the opposite.

[interested]

1 hour ago, Strange said:

not individually measurable.

yes agreed, the casimir effect only proves the existence of quantum fluctuations. 

Thanks for the wiki link ref zero energy, it was very interesting, I should have googled and found it myself, however I did not follow how zero energy is infinite. I will have to read it again. 

Random thought : Can space be viewed as maintaining  an average energy level over a volume of space.? I think I read a few years ago there was a theory based around this,  the memory is in the dim and distant past. I will google this myself.

18 hours ago, swansont said:

The vacuum energy is not zero, according to QM. In addition, the restriction of energy conservation is modified by the HUP. You can't say energy conservation has been violated on short time scales, as long as the uncertainty is consistent with the HUP.

Yes, in QFT also. Are the collapse of quantum fluctuations instantaneous. In QFT what are the boundaries of a Quantum fluctuation? 

[swansont]

2 minutes ago, interested said:

Are the collapse of quantum fluctuations instantaneous.

The time depends on the energy, in accordance with the HUP.

[interested]

4 minutes ago, swansont said:

As interaction exchange particles are virtual, I would disagree that they have no effect on matter. Quite the opposite.

The quantum foam in space as evidenced by the casimir effect are virtual particles and very short lived, the virtual particles used as exchange particles are way of simply stating the magnetic field is transmitted by virtual photons for instance, without defining the under lying shape of the wave or field causing the effect. 

4 minutes ago, swansont said:

 

[Strange]

1 hour ago, interested said:

however I did not follow how zero energy is infinite.

It isn’t infinite. But is non-zero. 

1 hour ago, interested said:

Can space be viewed as maintaining  an average energy level over a volume of space.? 

That sounds like the zero point energy. 

Or, possibly, dark energy. Which can also be described as the inherent energy of space. 

[interested]

21 minutes ago, Strange said:

That sounds like the zero point energy. 

Or, possibly, dark energy. Which can also be described as the inherent energy of space.

Are you trying to direct me at pop science articles and nutter theories  Here is one on zero point gravity, https://ac.els-cdn.com/S1875389212025151/1-s2.0-S1875389212025151-main.pdf?_tid=812b323f-a638-488b-abcf-91330c231328&acdnat=1524830042_8a8c50cb625d28ffb9f850780edd1e08 .

Also apparently energy is available free from the vacuum and its a government conspiracy why we havent found it yet, WOW.  

25 minutes ago, Strange said:

It isn’t infinite. But is non-zero. 

It was the wiki thread you posted that indicates it is infinite, but didnt show how it came to that conclusion.