[Bogie_smiles (OP)]

Reply #20

While I’m reading that PDF, you can watch this video, posted by Evan_au on a Bill S thread, “Could there be “static” instants of time?”
https://youtu.be/-6rWqJhDv7M
Carlo Rovelli The Physics and Philosophy of Time

In the video, Rovelli covers the topics that we science enthusiasts often think about. There is time that passes, and there is the way our brain deals with the passing of time. There is a lot of emphasis on the discrete nature of time at the quantum level, and on the difference between what goes on at the quantum level and what human individuals need to best function as living beings in an environment where what goes on at the quantum level is essentially irrelevant.


Rovelli is also one of the researchers named in the LQG Wiki in reply #19, which says, “There has also recently been work (2011) by Carlo Rovelli, et al. on relating LQC to the spinfoam-based spinfoam cosmology."

And there are plenty of clicks to more recent research.

[guest45734]

Quote from: dead cat on 31/08/2018 14:45:27

    Quote from: Bogie_smiles on 31/08/2018 13:27:43

        I have given my thoughts on related topics like the meaning of nothingness

    interesting!!!

People don't all agree on this definition so let me know how you would modify it.

Nothingness; No space, no time, no energy, and no potential for any space, time or energy

time  and gravity have both been shown to be emergent dependant on entanglement . space time cuvature is a consequence of entanglement.

[Bogie_smiles (OP)]

Reply #22

time  and gravity have both been shown to be emergent dependent on entanglement . space time curvature is a consequence of entanglement.

It is true that time and gravity are thought to be emergent in what is being referred to as a new paradigm; a follow-on and enhancement to Big Bang Theory with Inflation.

That is an important part of the theme of the paper I’m reading about the status of LQC. It is actually addressed specifically in the first of the five sections of the Introduction, Cosmological paradigms. That sections takes the reader through a brief historical evolution of cosmological thinking, and showing why there is a need for LQG and its related cosmology, LQC. The need is based on, among other things, the fact the space-time paradigm is not quantized and therefore doesn’t explain how things would work in the extreme energy densities that would have been experienced in the very early universe that evolved from a big bang. We now have a new paradigm: In the Beginning there was the Big Bang.

I consider that to be carefully worded in the paper, not to exclude preconditions to the big bang, but to be cautious not to invoke specific preconditions when there may or may not have been complete randomness from nothingness

Likewise, I think you are being cautious in how you worded your post, not to take a position on if you think the definition is aggressive enough to make the idea of something from nothing an impossibility.

[jeffreyH]

If you follow indeterminacy, then quantisation of time or space is not applicable. At the Planck scale there would be no way to determine if these measurements were discrete or continuous. Nevermind Zeno. In which case they may as well be considered continuous. This is a good thing for quantum mechanics. This is a different situation to quantum action. Where the Planck constant defines the quanta.

[Bogie_smiles (OP)]

If you follow indeterminacy, then quantisation of time or space is not applicable. At the Planck scale there would be no way to determine if these measurements were discrete or continuous.

I have to agree with that. Perhaps that is why I am looking at LQG first, instead of String Theory, though I could be wrong as to how ST deals with indeterminacy until I look closer.

Nevermind Zeno. In which case they may as well be considered continuous. This is a good thing for quantum mechanics. This is a different situation to quantum action. Where the Planck constant defines the quanta.

I know what you mean. Quantum mechanics is up for an overhaul, just like GR and inflation theory, if there is going to be a quantum solution to gravity.

The quantum of action, aka Planck’s constant, is too big and bulky to be the operative quantum of energy when you start looking deeper into quantum level interactions. Right off you have to question the idea that the fundamental particles of the standard model of particle physics are nothing more complicated than point particles with no internal composition.

Thanks for the comment. Here is the Wiki to Indeterminacy:
https://en.wikipedia.org/wiki/Quantum_indeterminacy
Quantum indeterminacy is the apparent necessary incompleteness in the description of a physical system, that has become one of the characteristics of the standard description of quantum physics.
Prior to quantum physics, it was thought that (a) a physical system had a determinate state which uniquely determined all the values of its measurable properties, and conversely(b) the values of its measurable properties uniquely determined the state.
Quantum indeterminacy can be quantitatively characterized by a probability distribution on the set of outcomes of  measurements of an observable. The distribution is uniquely determined by the system state, and moreover quantum mechanics provides a recipe for calculating this probability distribution.

Indeterminacy in measurement was not an innovation of quantum mechanics, since it had been established early on by experimentalists that errors in measurement may lead to indeterminate outcomes. However, by the later half of the eighteenth century, measurement errors were well understood and it was known that they could either be reduced by better equipment or accounted for by statistical error models. In quantum mechanics, however, indeterminacyis of a much more fundamental nature, having nothing to do with errors or disturbance.

[guest45734]

I think you are being cautious in how you worded your post, not to take a position on if you think the definition is aggressive enough to make the idea of something from nothing an impossibility.

every point in the vacuum of space time is full of entanglement (quantum fluctutions). there is no vacuum in space time except perhaps inside a blackhole where entanglement is reduced to a minimum and time slows, and space contracts, speculating perhaps to zero or exits via a singularity and a wormhole ER bridge to a whitehole etc yada yada
.
almost all versions of quantum gravity now appear to agree time and space are emergent depending on entanglement, Which version do you which to pursue do you have a specific paper on LQG or approach you wish to discuss on the subject.

[guest45734]

The basic Layman approach to LQG is that it seaks to unify quantum mechanics with einsteins relativity and the OTHER 3 funamental forces. ie it attempts to formulate an approach to gravity in exactly the same way as EFE (EFE predict dark matter exists). Other approaches such as MOND and various other emergent approaches to gravity do not predict dark matter exists and in fact do not agree with fully EFE's . According to Einstein, gravity is not a force – it is a property of space-time itself. Loop quantum gravity is an attempt to develop a quantum theory of gravity based directly on Einstein's geometric formulation, which according to some of the newer theories may not be completly correct.

I will continue to watch your thread to see if any entangled ideas emerge . If both time and space are emergent based on entanglement, and LQG doesnt include entanglement and and 

[Bogie_smiles (OP)]

Thanks dead cat. It is going to take me a couple of weeks to get through the material I have on my list, including the link you gave me earlier, (Dead cat’s link https://arxiv.org/pdf/1707.01012.pdf), and the 138 page paper I'm working through, (Status of LQC https://arxiv.org/pdf/1108.0893v2.pdf). I don't want to go off that path until I get through that material.  I do want to address your reply #26 too, and I invite you and other participants to post and comment on any of the paths that quantum gravity takes us since general discussion of QG is appropriate here.

[Bogie_smiles (OP)]

Reply #28

I think you are being cautious in how you worded your post, not to take a position on if you think the definition [of nothingness] is aggressive enough to make the idea of something from nothing an impossibility.

every point in the vacuum of space time is full of entanglement (quantum fluctutions). there is no vacuum in space time except perhaps inside a blackhole where entanglement is reduced to a minimum and time slows, and space contracts, speculating perhaps to zero or exits via a singularity and a wormhole ER bridge to a whitehole etc yada yada …

Why do I get the idea that you are not going to commit yourself on the definition of “nothingness” that I posted? Do you agree that if we define nothingness as no space, no time, no energy, and no potential for any space, time, or energy, then it would be impossible for anything to emerge from nothingness. The point I am making is that there was an apparent event we refer to as the big bang, but given the definition, it could not have come from or “emerged” from nothingness; it must have had preconditions that resulted in the big bang event. Do you agree or would you revise the definition of nothingness?
.

The basic Layman approach to LQG is that it seaks to unify quantum mechanics with einsteins relativity and the OTHER 3 funamental forces. ie it attempts to formulate an approach to gravity in exactly the same way as EFE (EFE predict dark matter exists). Other approaches such as MOND and various other emergent approaches to gravity do not predict dark matter exists and in fact do not agree with fully EFE's . According to Einstein, gravity is not a force – it is a property of space-time itself. Loop quantum gravity is an attempt to develop a quantum theory of gravity based directly on Einstein's geometric formulation, which according to some of the newer theories may not be completly correct.

Yes, that is a fair analysis. As for any of the newer theories being completely correct, I’m not finding they are said to be correct, and there is still a deviation between the math and the precise observations, which can be a hint that there is plenty more to know.

Any QG solution will have to fit as an extension from the best theories we have, to get to theories that give us a level of precision that satisfies the professional community. LQG probably is not going to be the answer, but when it comes to the links earlier in the thread, it is the one that I find most readable. I’m still working through the material, and hope to post my take on it after that. 

I will continue to watch your thread to see if any entangled ideas emerge . If both time and space are emergent based on entanglement, and LQG doesnt include entanglement and and 

I know what you mean. We have to go a step at a time, and there is plenty of time for laymen to try to understand what they are saying about quantum gravity. In the meantime, looking at and discussing the possibilities that come up as we read the professional level papers is a way of passing the time until the professionals reach their consensus. In general, those discussions will have to be within the NS guidelines, which are understandably more strict in the main science sub-forums.

[guest45734]

Why do I get the idea that you are not going to commit yourself on the definition of “nothingness” that I posted? Do you agree that if we define nothingness as no space, no time, no energy, and no potential for any space, time, or energy, then it would be impossible for anything to emerge from nothingness. The point I am making is that there was an apparent event we refer to as the big bang, but given the definition, it could not have come from or “emerged” from nothingness; it must have had preconditions that resulted in the big bang event. Do you agree or would you revise the definition of nothingness?

I stated earlier I find the subject interesting, I did not state I had answers but have already pointed out both time and space are likely emergent and are dependent on entanglement of space time.

The concept of ZERO energy depends on your reference point, what is zero energy Can all forms of known energy except space time be regarded as positive energy, could the development of space time be regarded as negative energy. This line of thought flows over to a zero energy universe theory. This theory as I am sure you are aware assumes the total energy of the universe is still zero, and has not deviated from this. The expansion of space time due to the cosmological constant/dark energy (and the curvature/contraction of space time due to gravity) may not be as a result of a big bang but may in actual fact be a a result of how space time and the universe develops in our reference frame.

 

I know what you mean. We have to go a step at a time, and there is plenty of time for laymen to try to understand what they are saying about quantum gravity. In the meantime, looking at and discussing the possibilities that come up as we read the professional level papers is a way of passing the time until the professionals reach their consensus. In general, those discussions will have to be within the NS guidelines, which are understandably more strict in the main science sub-forums.

I agree its a good way of killing time but just because a bunch of paid persons decide via a majority imaginary teapots or none existent dark matter exists and then put forward obfuscated arguments to explain their beliefs doesnt mean we have to believe them, especially when better or more logical ideas explain the observed universe better.

Serious discussions on new or developing theories are often done on closed forums, filtering out the chaff from the wheat on open forums is not easy, I tend to apply occams razor often cutting myself in the process If it doesnt involve entanglement and an appreciation of how space time develops then it doesnt cut the mustard for me. 

[Bogie_smiles (OP)]

I stated earlier I find the subject interesting, I did not state I had answers but have already pointed out both time and space are likely emergent and are dependent on entanglement of space time.


The concept of ZERO energy depends on your reference point, what is zero energy Can all forms of known energy except space time be regarded as positive energy, could the development of space time be regarded as negative energy. This line of thought flows over to a zero energy universe theory. This theory as I am sure you are aware assumes the total energy of the universe is still zero, and has not deviated from this. The expansion of space time due to the cosmological constant/dark energy (and the curvature/contraction of space time due to gravity) may not be as a result of a big bang but may in actual fact be as a result of how space time and the universe develops in our reference frame.

You did say that, and we miscommunicated.

I agree its a good way of killing time but just because a bunch of paid persons decide via a majority imaginary teapots or none existent dark matter exists and then put forward obfuscated arguments to explain their beliefs doesn’t mean we have to believe them, especially when better or more logical ideas explain the observed universe better.

I’m glad your brought up imaginary teapots and nonexistent dark matter and the obfuscated arguments to explain them. I respect your opinion which is completely opposite of mine on matters like the consensus views. I honor and respect you for the personal rigor that it takes for a layman to form opinions on subjects as difficult as energy and cosmology, and our discussions show we’re not pretending to be professionals, so we have some excuse for not always agreeing with main science views. So stay with me as I make a brief comparison between our views; you imply a degree of skepticism about the methods and motives behind consensus theory, and my view is to state appreciation of the difficulties professionals face when they set off to follow the scientific method and independently come up with different conclusions, lol.

Serious discussions on new or developing theories are often done on closed forums, filtering out the chaff from the wheat on open forums is not easy, I tend to apply occams razor often cutting myself in the process If it doesn’t involve entanglement and an appreciation of how space time develops then it doesn’t cut the mustard for me. 

We don’t have to agree on definitions of nothingness or “somethingness” , or even on entanglement or emergence to agree or be realistic about the direction of science.


You are bold and settled on your view, and that is great. Nevertheless, are you also of the view, like I am, that quantum gravity is the wave of the future? I’m hoping that a solution to QG comes up in my lifetime that professionals get their heads around, and together develop a new “paradigm” like occurred with general relativity. We could sure use a quantum gravity model that respects the work of professionals of the past, but moves forward to solve problems like the mechanics of zero energy or dark matter, which I hope QG does?


I’m still working through the links in order to get a feel for what they are saying about quantum gravity, but one conclusion I have come to so far is we don’t have to agree on specifying definitions, but we do have to understand what we mean specifically when we use common words that can have specific meanings in the context we use them. For that reason I ask, what do you mean by entanglement when you use it in the contexts of zero energy and of how space time develops? Give me a link you like, or tell me in your own words, but I want to be talking the same language as you when we get into entanglement matters.

[guest45734]

You are bold and settled on your view, and that is great.

My views change regularly, but my current interests flip between Verlindes theories and the holographic universe theories, they are closely linked but different. I joined this forum to discuss them. Mainstream thought is dark matter exists and space time is 4 dimensions, opportunities to get people to discuss more dimensions or different types of space is limited. Entanglement,  and quantum tunneling are normally only discussed around particles, Verlindes theories include space time entanglement not just particle entanglement. Space time as you are aware looking at the HUP is full of entangled virtual particles pairs which come into and out of existence continuously. I have posted lots of links on this subject but do not wish to hijack your thread, so will continue to watch and learn.

By the way what version of quantum gravity are you wanting to discuss, can you post a paper on exactly what you want to investigate it for perusal. Quantum gravity is a general term and means a lot to different people.

I think generally all theories are trying to model a space time that is expanding in open space, and contracting around masses/energy. ie the earth sucks Realistically it is impossible to model the entire universe in every detail, so generalisations are required. EFE do not attempt to model anything at the quantum level and assume space time is smooth, quantum effects are ignored. At the quantum level space time is anything but smooth, but when zooming out it becomes smooth.

http://backreaction.blogspot.com/2017/03/is-verlindes-emergent-gravity.html
In summary, Verlinde’s emergent gravity has withstood the first-line bullshit test. Yes, it’s compatible with general relativity.

[guest45734]

We don’t have to agree on definitions of nothingness or “somethingness” , or even on entanglement or emergence to agree or be realistic about the direction of science.

I think we maybe both 50% right and wrong on the definitions of nothingness and time. Is it possible that points in space time where neither space or time or energy existed, are continually coming into existence all the time. At the quantum level a mini bang and the beginning of time and space is continually happening as dark energy expands time and space. Zooming out we just view this as space time, ie from our perspective time and space is continually coming into existence adding to the whole of what we perceive giving us an assumed t = 0 at some perhaps not believable big bang.

Energy can not be created or destroyed, however space time obviously is. If gravity and dark energy are both viewed as fluctuations in space time and are considered negative energy. In a zero energy universe some form of positive energy must also be coming into existence to offset the new -ve energy, via possibly converting space time into matter. Could Hawking radiation on the edge of a black hole be converting space time into +ve energy by absorbing entangled space time. I know hawking radiation is supposed to allow the gradual evaporation of a black holes mass (BUT Big Bangs and super novaes are beyond the scope of your thread)
 

[Bogie_smiles (OP)]

Reply #33

My views change regularly, but my current interests flip between Verlindes theories and the holographic universe theories, they are closely linked but different. I joined this forum to discuss them. Mainstream thought is dark matter exists and space time is 4 dimensions, opportunities to get people to discuss more dimensions or different types of space is limited. Entanglement,  and quantum tunneling are normally only discussed around particles, Verlindes theories include space time entanglement not just particle entanglement. Space time as you are aware looking at the HUP is full of entangled virtual particles pairs which come into and out of existence continuously. I have posted lots of links on this subject but do not wish to hijack your thread, so will continue to watch and learn.

Have you seen this video?
https://youtu.be/vJi3_znm7ZE?list=WL
Hacking Reality, from Quantum Gravity Research youtube channel

If you can, watch it all the way, and let me know if you get through it.

Here is the E8 graphic to meditate on, lol.
https://www.thenakedscientists.com/forum/gallery/43933_19_09_18_1_42_48.jpeg
Here is a link to E8 theory, just to view:
https://answers.yahoo.com/question/index?qid=20070320003337AAUcOV1
E8 equation

It has been debunked so here is a link to the debunking:
https://www.sciencedaily.com/releases/2010/03/100326132341.htm
No simple theory of everything inside E8

By the way what version of quantum gravity are you wanting to discuss, can you post a paper on exactly what you want to investigate it for perusal. Quantum gravity is a general term and means a lot to different people.

The research is in several directions, and there is no consensus yet as to what path will be productive. As to my selected version, I noted that String theory has met with objections, as has Loop Quantum Gravity. My current reading is about LQG and its vehicle, Loop Quantum Cosmology, though I don’t predict where the ultimate solution will come from.

I think generally all theories are trying to model a space time that is expanding in open space, and contracting around masses/energy. ie the earth sucks Realistically it is impossible to model the entire universe in every detail, so generalisations are required. EFE do not attempt to model anything at the quantum level and assume space time is smooth, quantum effects are ignored. At the quantum level space time is anything but smooth, but when zooming out it becomes smooth.

http://backreaction.blogspot.com/2017/03/is-verlindes-emergent-gravity.html
In summary, Verlinde’s emergent gravity has withstood the first-line bullshit test. Yes, it’s compatible with general relativity.

From a layman science enthusiast perspective, the scientific papers are intriguing, but I don’t find that I can get much out of them in regard to exactly how a final version of QG will work mechanically (wave mechanics). The papers represent much of the material mathematically, but our minds can only visualize in 3D. So the “version of QG” that I am capable of discussing is one that starts from the bottom up and is restricted to the 3 dimensions of space and one of time. That means I look at the scientific explanations of physical observations in space like redshift, the observed separation of galactic structure (galaxies and galaxy groups under the influence of dark energy), and the microwave background (WMAP and Planck sky survey data), and apply quantum thinking.

The one thing that has to be considered is that quantum gravity will be about how gravity works at the quantum level, i.e., the detail of spacetime that smooths it out at the macro level. That is where I would take this discussion.

I think we maybe both 50% right and wrong on the definitions of nothingness and time. Is it possible that points in space time where neither space or time or energy existed, are continually coming into existence all the time. At the quantum level a mini bang and the beginning of time and space is continually happening as dark energy expands time and space. Zooming out we just view this as space time, ie from our perspective time and space is continually coming into existence adding to the whole of what we perceive giving us an assumed t = 0 at some perhaps not believable big bang.

Energy can not be created or destroyed, however space time obviously is. If gravity and dark energy are both viewed as fluctuations in space time and are considered negative energy. In a zero energy universe some form of positive energy must also be coming into existence to offset the new -ve energy, via possibly converting space time into matter. Could Hawking radiation on the edge of a black hole be converting space time into +ve energy by absorbing entangled space time. I know hawking radiation is supposed to allow the gradual evaporation of a black holes mass (BUT Big Bangs and super novaes are beyond the scope of your thread)

We will be pondering those things for a long time, but are you with me in regard to the fact that what they are saying about quantum gravity takes the discussion to what is physically going on at the quantum level, from the bottom up?

[guest45734]

I will watch the links but am on holiday at the moment, they will have to wait until I get back home.

The research is in several directions, and there is no consensus yet as to what path will be productive. As to my selected version, I noted that String theory has met with objections, as has Loop Quantum Gravity. My current reading is about LQG and its vehicle, Loop Quantum Cosmology, though I don’t predict where the ultimate solution will come from.

Its any ones guess, String theory has given rise to many insights in physics but no reliable predictions, such as the holographic universe and Verlindes entropic emergent gravity. My attraction to these two theories are they do not need dark matter or the graviton, are just about understandable, and include entanglement with the possibility of an additional dimension via wormholes in space time.

So the “version of QG” that I am capable of discussing is one that starts from the bottom up and is restricted to the 3 dimension of space and one of time

You may miss something with tunnel vision, but agreed the best way is from the bottom up. Big bang theory is from the top down is it not and is not completely correct according to the expanding universe theory, do you wish to bring a version of BB into the discussion.

[guest45734]

We will be pondering those things for a long time, but are you with me in regard to the fact that what they are saying about quantum gravity takes the discussion to what is physically going on at the quantum level, from the bottom up?

Edit :YES.


 

Have you seen this video?

Hacking Reality, from Quantum Gravity Research youtube channel

If you can, watch it all the way, and let me know if you get through it.

Here is the E8 graphic to meditate on, lol.
https://www.thenakedscientists.com/forum/gallery/43933_19_09_18_1_42_48.jpeg
Here is a link to E8 theory, just to view:
https://answers.yahoo.com/question/index?qid=20070320003337AAUcOV1
E8 equation

It has been debunked so here is a link to the debunking:
https://www.sciencedaily.com/releases/2010/03/100326132341.htm
No simple theory of everything inside E8

Ok as requested I went through the links. E8 theory is one I read about some time ago, but have not payed much attention too. The reason for this is that pesky graviton and lack of any entanglement mentioned in the whole theory. The reason I dont like the graviton or theories including it, is that it is supposed to get out of a black hole whilst having less energy than a gamma ray which apparently cant escape a BH. The graviton seems to change its characteristics according to requirement. If particles emit or absorb gravitons which have energy they will lose or gain energy. Many if not all theories have doubters as does string theory and E8 and many other theories, you have put forward a debunkers view on E8. E8 makes no predictions on the existence or otherwise of dark matter, it makes no claims to agree in part with EFE, its place may be in particle physics, not in modelling spacetime. It does however place if I am correct the additional E8 dimensions on top of space time, which gives it 11 dimensions like string theory. String theory uses strings and E8 uses rings I am lost .

Maths often obfuscates exactly what is happening when comparing different theories, pop science explanations often obfuscates it even further, as I think the video does. EFE explain many things, and accurately predict many things to amazing accuracy. Dark matter, MIGHT be stretching EFE beyond breaking point. Observations do not support the existence of dark matter but do suggest that MOND or another form of emergent gravity may be correct. Keeping an open mind, what is your take on what you posted for everyone to go through.

There a number of lengthy papers on E8 on the arxiv archive which you may want to read. I am wading through stuff on entropic emergent gravity as defined initially by Verlinde and others which is way more interesting at the moment. Basically all the different ideas are converging on a final theory of everything MAYBE .   

[Bogie_smiles (OP)]

Reply #36

Its any ones guess, String theory has given rise to many insights in physics but no reliable predictions, such as the holographic universe and Verlindes entropic emergent gravity. My attraction to these two theories are they do not need dark matter or the graviton, are just about understandable, and include entanglement with the possibility of an additional dimension via wormholes in space time.

So the “version of QG” that I am capable of discussing is one that starts from the bottom up and is restricted to the 3 dimension of space and one of time

You may miss something with tunnel vision, but agreed the best way is from the bottom up. Big bang theory is from the top down is it not and is not completely correct according to the expanding universe theory, do you wish to bring a version of BB into the discussion.

Every cosmological model is incomplete, but they are professional level models intended to make sense out of what we physically observe.

I do have a version of Big Bang Theory that I work from. It is very simple and generally accepted, starting from a big bang event. It is an accumulation of physical observations that fit into the Big Bang event scenario, including Inflation, the redshift data, accelerating expansion/dark energy), the cosmic microwave energy background radiation observations (CMBR), and the WMAP and Planck sky surveys, and many other links, many of which are embedded in those major topics.

The initial event to which our observable universe is connected has a visible portion and a major causally connected “as yet” unobservable portion. The observable portion is our Hubble view which covers about one twenty-four millionth of the sky (1/24,000,000):
https://en.wikipedia.org/wiki/Hubble_Deep_Field
That view can be considered to be essentially what the Hubble telescope would see in every direction across all of the 24 million snapshots that make up the whole spherical field of observable space.
Keeping that Hubble view in mind, here is a list of some of the related links that make up the rest of my working version of Big Bang Theory with Inflation (consider the list open for additions from anyone, subject to discussion):
Big Bang Event
Inflation
Redshift
Accelerating expansion/dark energy
The Cosmic Microwave Background Radiation observations (CMBR) WMAP sky temperature survey
Planck sky survey
and related links.

The observations of type Ia supernovae that are used to measure the rate of acceleration support the popular media perspective of a universe that has grown so fast and so big that it makes sense to conclude that the universe is expanding at an accelerating rate everywhere.

[Bogie_smiles (OP)]

Reply #37

Yes, [to a layman discussion of QG starting from the bottom up].
…

More power to you in your study and contemplation. Your own work is most important, but having someone responding to this thread has been an encouragement. Hopefully you will find a moment from time to time to post here in this effort to gain a bottom up layman understand of QG.

From the links about a general working version of Big Bang Theory in reply #36, I hope members generally agree that the most significant observation that makes BBT (including Inflation) so compelling is the observed separation of galaxies and galactic structure taking place at an accelerating rate. BBT is the macro level context within which much of the micro level quantum gravity research is taking place, and the QG effort focused on here is about applying quantum thinking to unite general working versions of BBT, with the extensive research and quantum level theories about QM.

Thus in this thread we are putting the focus inward, as if we were looking at the quantum world through the opposite end of the Hubble telescope. Like with the macro view, we can only see to limited depths, but that limited micro view stimulates an intellectual environment where quantum gravity theories abound at the professional level, and where the interest of layman science enthusiasts can be sparked.

The perspective one can get from reviewing the resulting papers on QG is that a good place to start is with virtual particles, and right away you know you are in the realm of quantum field theory. The uncertainty principle is immediately invoked, and applies in regard to what amount of mass a VP might have, where it is, and where it is going, though the Wiki insists that they always conserve energy and momentum.

Ordinary particle interactions require exchanges of virtual particles, and that is where Feynman diagrams are employed to show virtual particles as the lines between the various interacting real particles. However, being comfortable with real particles is not going to have a good outcome for you, because “real” particles aren’t all that real down in the realm of QFT; real particles are excitations of underlying fields. So when real particles interact, the interactions are between field excitations that persist and that can leave lasting effects on the “real” particles, while the virtual particles that appeared are field excitations that are temporary, and that fade away as the real particles move on.

Simple layman logic says that the virtual particles appear as a result of energy contained by known particles that interact, and they appear in and around the point of interaction, observed at best as interference patterns. They borrow wave energy provided by virtual photons, for example, which are predicted to be the carriers of energy between particles as they interact, but return that energy to space as they fade and disappear.


Comment freely.

[jeffreyH]

If you want to brush up on virtual particles then read this article by Matt Strassler.
Virtual Particles:What are they?

[Bogie_smiles (OP)]

Reply #39

The Strassler article presents a much different view of virtual particles than the Wiki article I was going to quote, and is a good fit for a layman discussion of both virtual, and real particles. It cautions us not to consider virtual particles to have the same effects on the field as real particles. The field responds to the presence of real particles based on the nature of the individual particles, and virtual particles do not have established frequencies, charges or energy levels like pre-existing real particles.

It points out that the natural motion of real particles through the field is “smooth” relative to the effect of virtual particles, because virtual particles are attributed to unpredictable random disturbances caused when they pop in and out of existence. The article acknowledges that a natural motion in the field that is characteristic of the presence of the real particles, is not characteristic of virtual particle disturbances in the field. Real particles remain stable as they traverse space, while the presence of virtual particles is temporary and will die away and disappear as the virtual particle disappears.

But don’t take that layman level explanation at face value, read the Strassler article and start to form a new impression of not only what he says virtual particles are like, but what “real” particles are like too. I touched on it in reply #37 when discussing the Wiki link to Virtual Particles, and so be sure to read that whole link at the Wiki source.

If we compare the field to the quiet surface of water of a pond, I see the comparison as being like the evolving continuous wake that spreads out on the surface behind a toy boat (real particle) that is being propelled by a breeze, as opposed to the circular ripple that appears and dissipates when you drop in a pebble (virtual particle).