QFT: Every particle is an excitation of it's own field?

[swansont]

1 minute ago, Silvestru said:

Hmm why are we so sure that the net energy of the universe is zero? I am not debating this, I am just curious, what observational data do we have for this?

I'm not aware that we know one way or another. But if one going to assume that it is, I'd like to know the justification for it.

1 minute ago, Silvestru said:

I know we mentioned before but how are we talking about the energy of an isolated system which is unchanging with time and is not stationary and we have to measure it as an observer sitting "outside" of it. Oh and also it's expanding. 

Does the expansion require net energy?

[Silvestru]

6 minutes ago, swansont said:

I'm not aware that we know one way or another. But if one going to assume that it is, I'd like to know the justification for it.

Good point  thanks.

7 minutes ago, swansont said:

Does the expansion require net energy?

I thought that the expansion is a good argument that the net energy is zero.

[swansont]

6 minutes ago, Silvestru said:

 I thought that the expansion is a good argument that the net energy is zero.

I don't think it rules out the scenario where we have a net energy.  

[Silvestru]

2 minutes ago, swansont said:

I don't think it rules out the scenario where we have a net energy.  

It's hard to say, the expansion that points towards zero net energy is based on the concept of Inflation and that dark energy fills expanding space like some sort of constant. As expansion takes place, dark energy and gravitational energy are simultaneously created and even themselves out.

I am afraid to speculate as virtually all of the concept above are hypothetical and we don't know yet what dark energy is.

Just now, Silvestru said:

dark energy and gravitational energy are simultaneously created and even themselves out.

Hmm I take back the term "created" for dark energy.  It "expands" is better.

[swansont]

5 hours ago, Silvestru said:

It's hard to say, the expansion that points towards zero net energy is based on the concept of Inflation and that dark energy fills expanding space like some sort of constant. As expansion takes place, dark energy and gravitational energy are simultaneously created and even themselves out.

I don't think we know that this is the case. And if the expansion has to do work, then some original energy would be required. So in this naive treatment, I don't think anything is ruled out.

5 hours ago, Silvestru said:

I am afraid to speculate as virtually all of the concept above are hypothetical and we don't know yet what dark energy is.

And that's a huge part of the problem. We don't know this, and we don't know what has the dark energy.

[Butch]

8 hours ago, swansont said:

Can you show that the energy had to "come from" somewhere? i.e. that the net energy of the universe is nonzero?

No. Well, the universed is expanding... IF that expansion includes fields and matter then we have duplicity, relative to our experience it is not expanding (although we would detect red shift). If "space" alone is expanding we could expect a net energy of zero.

I have to admit however that my thoughts on light speed seem to indicate the universe is closed, there must be "back pressure" of some sort... Perhaps however only our observable universe is closed?

7 hours ago, Silvestru said:

Based on your speculation:

 

1. If Energy in Our Universe is coming from Other Universes the question continues, where do the other Universes that are giving us Energy have theirs from? (please don't say other other Universes)

2. How are the BH from other Universes interacting with ours? How does the energy appear? Like from a "white whole", the other end of a black whole like a garden hose? And when did this energy start coming? Before during or after the BB?

3. What if I confidently tell you that the total energy in the Universe is negative because of gravity that only attracts? Would you believe me?

 

All good questions (the essence of science!)

I would not believe you... In a universe where expansion was absolute bodies would seem to attract one another... If you drop a penny does it fall to earth or do they both expand until they meet?

I enjoy the discussion, however I really only introduced my speculation in the hope of hearing some other speculations.

BTW, about dropping the penny, there is an explanation for orbits and the impetus for initial attraction of bodies... If you wish I can elaborate, however I will do so by opening a new topic in speculations.

Edited April 18, 2018 by Butch

[Mordred]

 Incorrect on light speed being involved with an open or closed universe. The speed limit does not rely upon wheher or not the universe is open or closed.  It is simply the speed of information exchange maximum. No cause is needed.

 Space itself is simply volume. The universe expands or contracts depending on the thermodynamic laws. It will cool down as the universe expands just like any ideal gas does ie PV=NrT. Though the precise application is the formula for an adiabatic and isentropic fluid.

 It is precisely the same formula under those two conditions as it is for a classical gas in statistical mechanics.

This article will get you started its not the greatest but its math level is lower

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.uio.no/studier/emner/matnat/fys/FYS4130/v10/undervisningsmateriale/Cosmology.pdf&ved=2ahUKEwiriIier8XaAhUF8GMKHSiVDZIQFjAAegQICBAB&usg=AOvVaw0jph7ZkMGUqUdYHArIOIir

It is an introductory level on the equations of state (thermodynamic term precise same application) and the FLRW metric with a small amount of GR.

 

Edited April 19, 2018 by Mordred

[Silvestru]

12 hours ago, swansont said:

I don't think we know that this is the case. 

I was just laying out the concept so we know what we are talking about. I did not support this hence the following: "I am afraid to speculate as virtually all of the concept above are hypothetical."

12 hours ago, swansont said:

And if the expansion has to do work, then some original energy would be required. So in this naive treatment, I don't think anything is ruled out.

It's dangerous with so many unknowns to go further with this discussion and I have to be careful but what about vacuum energy? (Virtual particles, matter and anti-matter, appear "from nothing" and annihilate themselves immediately.) 

Does this not affect the expansion? You are saying that it was impossible for this to spark it off which seems logical but what did?

I know you don't like to wander off to far into the hypothetical but I wold like to hear your thoughts.  

 

[swansont]

42 minutes ago, Silvestru said:

 It's dangerous with so many unknowns to go further with this discussion and I have to be careful but what about vacuum energy? (Virtual particles, matter and anti-matter, appear "from nothing" and annihilate themselves immediately.) 

Does this not affect the expansion? You are saying that it was impossible for this to spark it off which seems logical but what did?

I know you don't like to wander off to far into the hypothetical but I wold like to hear your thoughts.  

I don't know if it affects the expansion. We don't know how much vacuum energy is available to us, or to the universe.

[Silvestru]

Thank you swansont. 

I figured I would just add this paper on "VACUUM ENERGY AND THE COSMOLOGICAL CONSTANT" for other interested member with the mention that this does not link or specify that the vacuum energy is affecting or causing the expansion. It's just a read on this subject.

https://arxiv.org/pdf/1503.05483.pdf

[MarkE]

23 hours ago, Silvestru said:

3. What if I confidently tell you that the total energy in the Universe is negative because of gravity that only attracts? Would you believe me?

We live in a flat Universe in which the value of the combined energy is 1, and that of gravity is 1. The law of conservation of energy states that energy can only change in form, never increase its amount. So if all of the energy during the beginning of the Big Bang had the value of 1, that same energetic value applies to the Universe we have right now, even though there are lots of particles around. All the particles of the Universe together still make up that initial value of 1, so the composition of the distribution of energy in the Universe has changed, and is continuously changing, but the energy value itself can’t change. So you can’t add anything, only divide what you already have.

Taken this in account, it has been proposed by Edward P. Tryon that the Universe may be a large-scale quantum-mechanical vacuum fluctuation, where positive mass-energy is balanced by negative gravitational potential energy, a reference to measurements that indicate that we’re living indeed in a flat Universe. The inflation theory, which came later, was able to explain how our Universe could inflate from a tiny particle.

Before fermions, there must have been bosons, matter before energy. Why? Well, if you start off with a hot Universe, and you let it cool down, you’ll predict that you wind up with about 74% hydrogen and about 24% helium by mass, which is the initial composition of every star. Our sun right now consists of about 62% helium (because it's about 5 billion years old), but initially this was 24%. And all elements, except hydrogen and helium, are made in a star. If the Big Bang were to generate the right amount of helium and other light nuclei, then there must have been an era in the early history of our Universe in which light, not matter, made up most of the energy.

That being said, what I still don’t fully grasp is, if this is indeed the explanation of how our Universe came into being, and photons could have pair produced into + and – particles, then how did these newly created matter/antimatter particles further divide (because ‘adding’ energy is not allowed), and give rise to other particles, which lead to this Universe that is filled with photons and matter/antimatter particles?

They couldn’t, of course, because, as Sensei clearly remarked:

On 4/12/2018 at 2:02 PM, Sensei said:

Electron/positron can't decay anymore (at least according to current Standard Model knowledge..), but can e.g. annihilate with its anti-particle. And as a result, different set of particles (and eventually anti-particles) will appear instead.

Photons are able to divide (pair produce), but electrons/positrons can't. If these matter/antimatter particles could only undergo change by annihilating with each other to form photons again, then this process could only have taken place back and forth, and this could never have yielded the Universe we live in today.

Therefore there must be something else going on than just ‘quantum fluctuations’, and photons that turn into matter/antimatter particles, because the initial particles that made up the early Universe couldn’t just change form by dividing themselves further and further.

Edited April 19, 2018 by MarkE

[Silvestru]

15 minutes ago, MarkE said:

We live in a flat Universe in which the value of energy is 1, and that of gravity is 1.

What does this mean? I saw this confusion before,  do you mean the density parameter? And what about gravity? what do you mean it's value is 1?

Quote

General relativity explains that mass and energy bend the curvature of spacetime and is used to determine what curvature the universe has by using a value called the density parameter, represented with Omega (Ω). The density parameter is the average density of the universe divided by the critical energy density, that is, the mass energy needed for a universe to be flat. Put another way,

•  If Ω = 1, the universe is flat
•  If Ω > 1, there is positive curvature
•  if Ω < 1 there is negative curvature

 

20 minutes ago, MarkE said:

All the particles of the Universe together still make up that initial value of 1.

Can you provide a source for this?  What do you base this on? 

22 minutes ago, MarkE said:

The inflation theory, which came later, was able to explain how our Universe could inflate from a tiny particle.

That is not what it describes. What do you mean from a tiny particle?

[MarkE]

1 minute ago, Silvestru said:

Can you provide a source for this?  What do you base this on? 

I'm referring to the zero-energy Universe, which states that that matter (positive) is cancelled out by gravitational attraction (negative). Furthermore, the observations support it. There is a constant in the Friedmann–Lemaître–Robertson–Walker metric that determines whether the Universe is curved and infinite, curved and finite, or flat. The energy densities for those three curvature cases are +, - and 0. General relativity isn't valid at Planck time, or when the density of the Universe is greater than the Planck density. That needs quantum gravity (which we don't have). Extrapolation back to conditions like the Planck units is not legitimate.

[StringJunky]

3 hours ago, swansont said:

I don't know if it affects the expansion. We don't know how much vacuum energy is available to us, or to the universe.

Is the vacuum energy part of the total energy?

[Silvestru]

Wait, let's think about this for a second. I am questioning your quote below asking for a source.

48 minutes ago, MarkE said:

All the particles of the Universe together still make up that initial value of 1.

We live in a flat Universe in which the value of the combined energy is 1 .

You provide me a hypothesis which states that "The zero-energy universe hypothesis proposes that the total amount of energy in the universe is exactly zero".

So your source for saying that the combined energy in the universe is 1(which makes no sense) is a hypothesis that says it adds up to 0?

18 minutes ago, MarkE said:

Furthermore, the observations support it. There is a constant in the Friedmann–Lemaître–Robertson–Walker metric that determines whether the Universe is curved and infinite, curved and finite, or flat. The energy densities for those three curvature cases are +, - and 0. General relativity isn't valid at Planck time, or when the density of the Universe is greater than the Planck density. That needs quantum gravity (which we don't have). Extrapolation back to conditions like the Planck units is not legitimate.

I mentioned this just above. Where did you use the word density before this? 

18 minutes ago, MarkE said:

The energy densities for those three curvature cases are +, - and 0.

"The density parameter is the average density of the universe divided by the critical energy density, that is, the mass energy needed for a universe to be flat".

27 minutes ago, Silvestru said:

We live in a flat Universe in which the value of gravity is 1.

Can I please have a source for this?  I want to understand what you mean. 

Edited April 19, 2018 by Silvestru

[swansont]

26 minutes ago, StringJunky said:

Is the vacuum energy part of the total energy?

I would assume so, but that may be a distraction. If we can't access the energy, or it otherwise has no effect, it's moot. What matters is differences in energy — there are situations where you arbitrarily set an energy to zero (such as two masses or charges infinitely far apart), but the physics works just fine if you choose some other value,because that value cancels out in all of the calculations.

[MarkE]

26 minutes ago, Silvestru said:

Wait, let's think about this for a second. I am questioning your quote below asking for a source.

You provide me a hypothesis which states that "The zero-energy universe hypothesis proposes that the total amount of energy in the universe is exactly zero".

So your source for saying that for saying that the combined energy in the universe is 1(which makes no sense) is a hypothesis that says it adds up to 0?

It’s an hypothesis indeed, just like the heat death of the Universe, but in the absence of a more probable theory, Occam’s razor requires that the one with the fewest assumptions should be selected. I’ve provided evidence and measurements that support this hypothesis. If you have information for me I didn't take in account yet, please share, and I will reconsider, but so far, this is the most probable explanation.

Furthermore, it would make sense on other fields as well, since conservation of charge is a related principle to Maxwell’s equations, and even a requisite according to Noether’s theorem. Take also in account that the concept of general relativity doesn't view gravity as a force, rather as a curvature of spacetime, created by light (which is massless, but still attracted to it), just the way a field could be viewed as an excitation generated by a particle.

26 minutes ago, Silvestru said:

So your source for saying that for saying that the combined energy in the universe is 1(which makes no sense) is a hypothesis that says it adds up to 0?

The combined energy must be 1, and can’t become more or less than 1, because otherwise the law of conservation of energy would be violated. It could only become 2 if they would both represent 1/2 and 1/2.

Edited April 19, 2018 by MarkE

[StringJunky]

4 minutes ago, swansont said:

I would assume so, but that may be a distraction. If we can't access the energy, or it otherwise has no effect, it's moot. What matters is differences in energy — there are situations where you arbitrarily set an energy to zero (such as two masses or charges infinitely far apart), but the physics works just fine if you choose some other value,because that value cancels out in all of the calculations.

Yes, it''s moot when when it's just energy but it can produce quantum-sized particles, albeit briefly, can't it?

[Silvestru]

4 minutes ago, MarkE said:

Take also in account that the concept of general relativity doesn't view gravity as a force, rather as a curvature of spacetime, created by light.

Gravity is created by light huh? I'm afraid to ask for a source.

 

6 minutes ago, MarkE said:

The combined energy must be 1, and can’t become more or less than 1, because otherwise the law of conservation of energy would be violated.

I don't know how you can say this. The clue is in the name: "Zero-energy universe"! not "1 Energy Universe". (read you hypothesis again)

Also, the combined energy must be 1 what? joule? 

[MarkE]

2 minutes ago, Silvestru said:

Gravity is created by light huh? I'm afraid to ask for a source.

Without energy there wouldn't be any gravity. What would it attract?

Edited April 19, 2018 by MarkE

[StringJunky]

Just now, Silvestru said:

Gravity is created by light huh? I'm afraid to ask for a source.

 

Photons have energy-momentum and can curve spacetime, I think

[Silvestru]

3 minutes ago, MarkE said:

Without energy there wouldn't be gravity of course. What would it attract?

And to you energy means photons? How is light creating gravity? Can you explain the process?

Just now, StringJunky said:

Photons have energy-momentum and can curve spacetime, I think

I did not dispute this. Marke said that gravity is created by light. Not that photons influence the gravitational field.

[StringJunky]

3 minutes ago, Silvestru said:

I did not dispute this. Marke said that gravity is created by light. Not that photons influence the gravitational field.

Same things, just different terms.

Edited April 19, 2018 by StringJunky

[Silvestru]

Photons have an energy proportional to their frequency. They source a gravitational field and bend space-time, just like any other mass but gravity is not created by them.

 

Just now, StringJunky said:

Same thing.

Ok. Then I say that gravity is created by Fermions...

1 hour ago, MarkE said:

We live in a flat Universe in which the value  of gravity is 1.

I'm still waiting for a source for this MarkE. :(

[StringJunky]

2 minutes ago, Silvestru said:

Photons have an energy proportional to their frequency. They source a gravitational field and bend space-time, just like any other mass but gravity is not created by them.

 

Ok. Then I say that gravity is created by Fermions...

Gravity is curved spacetime and photons curve it, therefore, photons "create" gravity.