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Author Topic:   Ruling out an expanding universe with conventional proofs
Alphabob
Member (Idle past 1289 days)
Posts: 55
Joined: 06-28-2013


Message 166 of 223 (705525)
08-28-2013 12:24 PM
Reply to: Message 156 by Percy
08-27-2013 1:03 PM


Re: Kook Report
quote:
Getting involved in discussions about whether or not you're a crank is the kind of things cranks do. The rest of your behavior is also just like a crank. Cranks are unable to make their ideas comprehensible to laypeople, and they prefer less to discuss their ideas than complain about perceived censorship and ill treatment.

It's not that I care if I'm called a crank or whatever, but more of people making up their own definitions for words. If your going to accuse someone of being something, then you might want to at least have an understanding of the basic meaning. What is being argued for with respect to "crank" or "censorship" couldn't be farther from the actual definition. It seems to me like these personal definitions are somewhat made up in order to further individuals own interests rather than have a logical discussion. If someone were to grab an article or website with a legit definition and make an argument, that would be different.

More importantly, "In Internet slang, a troll is a person who sows discord on the Internet by starting arguments or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community (such as a forum, chat room, or blog), either accidentally or with the deliberate intent of provoking readers into an emotional response or of otherwise disrupting normal on-topic discussion"


This message is a reply to:
 Message 156 by Percy, posted 08-27-2013 1:03 PM Percy has acknowledged this reply

Replies to this message:
 Message 168 by Theodoric, posted 08-28-2013 2:07 PM Alphabob has not yet responded

    
Alphabob
Member (Idle past 1289 days)
Posts: 55
Joined: 06-28-2013


Message 167 of 223 (705531)
08-28-2013 1:28 PM
Reply to: Message 159 by Son Goku
08-27-2013 2:42 PM


Re: Questions.
I think you are missing the point on a lot of my answers.

quote:
This doesn't really make much sense as a response to my statement.

I said that "Quantum Mechanics is not derived from Classical Field Theory". That is, the principles of quantum mechanics were/are not developed out of the physics of classical field theory.

Saying that the electromagnetic field tensor* is in the Lagrangian has nothing to do with this.

As an analogy, imagine if I had made the statement that "Darwin did not deduce evolution from medical descriptions of the liver". Your response would be equivalent to "But this evolutionary textbook has a chapter about the liver".


My response is similar to saying differential geometry is derived from calculus. Although QED has the Dirac field for the electron's position and momentum (within the ensemble perspective), there is also the photon's field. This is the classical electromagnetic field and since classical field theory is defined by the interaction of fields with each other and/or other particles, it is safe to say that QM is indeed derived from classical field theory. Of course there are some additional rules for introductory QM or fields for QFT, but the entire foundations are based upon classical field theory.

quote:
Quantum mechanics doesn't rest on the position and momentum of the electron. It can describe any particle we've currently observed, none are fundamental to the formalism.

The only observables in basic QM are position and momentum, i.e. the uncertainty principle. I never said the electron was the only type of particle, that depends on the specific theory being referenced to. Are you saying that the Schrodinger equation describes the probability of any other particle besides the electron?

quote:
Wow, QED increases the degrees of freedom from conventional quantum mechanics by an infinite amount!
In the quantum mechanical theory of an electron in a potential there are only six degrees of freedom, the spatial coordinates of the spin up and spin down component of the electron (i.e. x,y,z position of each spin).

It reduces the degrees with respect to coupling additional fields in the equations, not with respect to basic QM.

quote:
The addition of probability turns it into a completely different theory, described using a completely different branch of mathematics, with entirely different predictions.
Also the classical version of the Lagrangian already has spin.

Not for the Schrodinger equation, it needs to be included with Pauli matrices; the Dirac equation includes it though. Of course it is going to change it into a different theory, but the observables and forces are all from classical theory.

quote:
The Dirac field doesn't describe position or momentum, so I don't understand what this means. The Dirac field is an object which fills spacetime and which commonly has excitations known as electrons. Can you explain what your statement means.

The probability density is defined directly from the dirac field, which provides the position and momentum distribution for an ensemble of all possible states. The inclusion of spin complicates the direct interpretation of the wavefunction; however, position and momentum can still be obtained from it.

quote:
A classical spinor can be viewed this way. That is, a single spinor can be viewed this way. However, a spinor field, where you now have a spinor at each point in spacetime can not.

A spinor field is simply an ensemble of classical spinors and is well described by the space-time algebra approach.

quote:
More importantly: You seem to be conflating the Dirac field and the electron in your writings. Electrons are excitations of the Dirac field.

If the Dirac field is directly related to position probability, then a higher probability would essentially make the likelihood of finding an electron there higher. I suppose you could consider this to be an excitation of the Dirac field, but in reality it's only an increased region for finding an electron due to the underlying field/particle dynamics.

quote:
That is not the definition used in physics. That sounds more like wave-function collapse.

Yes, but it is a legit definition. Wave-function collapse is a different concept. What I'm working on is the path integral formulation along one of the infinitely possible trajectories. I'm saying that this single particle perspective for an electron has an electric field, intrinsic spin and a gravitational potential. To get the QED results, all that is needed is the ensemble interpretation of this semi-classical field(s).

Edited by Alphabob, : No reason given.

Edited by Alphabob, : No reason given.

Edited by Alphabob, : No reason given.

Edited by Alphabob, : No reason given.


This message is a reply to:
 Message 159 by Son Goku, posted 08-27-2013 2:42 PM Son Goku has responded

Replies to this message:
 Message 171 by Son Goku, posted 08-28-2013 4:08 PM Alphabob has responded

    
Theodoric
Member
Posts: 5765
From: Northwest, WI, USA
Joined: 08-15-2005
Member Rating: 3.3


Message 168 of 223 (705538)
08-28-2013 2:07 PM
Reply to: Message 166 by Alphabob
08-28-2013 12:24 PM


Re: Kook Report
So you are a troll? Not a crank?

Facts don't lie or have an agenda. Facts are just facts

"God did it" is not an argument. It is an excuse for intellectual laziness.


This message is a reply to:
 Message 166 by Alphabob, posted 08-28-2013 12:24 PM Alphabob has not yet responded

    
Theodoric
Member
Posts: 5765
From: Northwest, WI, USA
Joined: 08-15-2005
Member Rating: 3.3


Message 169 of 223 (705540)
08-28-2013 2:11 PM


Alphabob vs. Son Goku
This ought to be fun.

Won't be pretty, but it will be fun.

How long till Alphabob claims victory and leaves the discussion?


Facts don't lie or have an agenda. Facts are just facts

"God did it" is not an argument. It is an excuse for intellectual laziness.


Replies to this message:
 Message 170 by Percy, posted 08-28-2013 2:46 PM Theodoric has not yet responded

    
Percy
Member
Posts: 15645
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.3


Message 170 of 223 (705542)
08-28-2013 2:46 PM
Reply to: Message 169 by Theodoric
08-28-2013 2:11 PM


Re: Alphabob vs. Son Goku
Theodoric writes:

How long till Alphabob claims victory and leaves the discussion?

It wouldn't surprise me at all if Son Goku quits first. I didn't expect this, but it seems that Alphabob is now adopting the same approach on the technical side that he's using on the crank issue. He doesn't care whether he's right or makes sense, he just wants to be contentious. Illumination is not his goal, in fact the opposite. He seems to have a large emotional investment in winning rather than in getting things right.

--Percy


This message is a reply to:
 Message 169 by Theodoric, posted 08-28-2013 2:11 PM Theodoric has not yet responded

    
Son Goku
Member
Posts: 1069
From: Ireland
Joined: 07-16-2005


(1)
Message 171 of 223 (705546)
08-28-2013 4:08 PM
Reply to: Message 167 by Alphabob
08-28-2013 1:28 PM


Re: Questions.
I think you are missing the point on a lot of my answers.

Probably, but you have admitted to using non-standard terminology of your own invention.

Although QED has the Dirac field for the electron's position and momentum (within the ensemble perspective), there is also the photon's field.

The Dirac field is not used to describe an electron's position and momentum. Electrons are excitations of it. See "Peskin and Schroeder: An Introduction to Quantum Field Theory, Chapter 3".

This is the classical electromagnetic field and since classical field theory is defined by the interaction of fields with each other and/or other particles, it is safe to say that QM is indeed derived from classical field theory. Of course there are some additional rules for introductory QM or fields for QFT, but the entire foundations are based upon classical field theory.

I'm sorry, but this is completely false. The particular quantum theory that we happen to be discussing is related to a classical field theory, but there are several relativistic quantum theories that cannot be related to classical fields. See for example the discussion in Araki's book "Mathematical Theory of Quantum Fields", the second and third chapters. There are similar comments in Haag's monograph "Local Quantum Physics".

Even historically, quantum mechanics was not derived from classical field theory.

The only observables in basic QM are position and momentum, i.e. the uncertainty principle.

The uncertainty principle does not state that position and momentum are the only observables in QM.
The closest true statement to what you are saying is that all observables are functions of position and momentum. However that is only true in quantum mechanics, not quantum field theory.

Are you saying that the Schrodinger equation describes the probability of any other particle besides the electron?

Of course it can, the Schrdinger equation is a whole class of equations, describing different particles in different potentials.

It reduces the degrees with respect to coupling additional fields in the equations, not with respect to basic QM.

Think about it, introducing additional fields could only increase the degrees of freedom.

Not for the Schrodinger equation, it needs to be included with Pauli matrices;

Where did the Schrdinger equation come from? I said the classical version of the Lagrangian has spin.

Look at it this way, Quantum Electrodynamics is a relativistic quantum field theory. Get rid of the "quantum" part and you have classical spinor electrodynamics, which has spin, this is the classical version of the theory that I mentioned.

The Schrdinger equation comes from removing the "field" and "relativistic" parts. In other words you are confusing two completely different reductions of the theory.

A spinor field is simply an ensemble of classical spinors and is well described by the space-time algebra approach.

Point me to a reference for this statement. By spacetime algebra, I assume you mean the Clifford algebra in 3+1 dimensions. Yes, this algebra can be used to manipulate the spinor/Dirac field (the field the electron is an excitation of) mathematically, however the interpretation you mention really only makes sense for the single spinor associated with an electron, not the spinors of the Dirac field. These spinors are two seperate objects. Again see Peskin and Schroeder: Chapter 3 to get an idea of this.

If the Dirac field is directly related to position probability

It is not. See any introductory textbook on quantum field theory. The second section of Mark Schrednicki's textbook will demonstrate this to you. Or Part 1 of Anthony Zee's textbook. I can get you the exact page numbers if you wish.

What I'm working on is the path integral formulation along one of the infinitely possible trajectories.

How can one have a path integral over one trajectory? The path integral is an integral over all trajectories of the Dirac field, not a single trajectory of an electron.

To get the QED results, all that is needed is the ensemble interpretation of this semi-classical field(s).

Exactly what do you mean here? If it is what I think it means, i.e. you can get QED with classical fields + ensembles, then there is a solid mathematical proof that this is false.
This message is a reply to:
 Message 167 by Alphabob, posted 08-28-2013 1:28 PM Alphabob has responded

Replies to this message:
 Message 182 by Alphabob, posted 08-30-2013 2:18 PM Son Goku has not yet responded

  
Son Goku
Member
Posts: 1069
From: Ireland
Joined: 07-16-2005


(3)
Message 172 of 223 (705576)
08-29-2013 5:31 AM
Reply to: Message 165 by New Cat's Eye
08-28-2013 9:31 AM


Re: Questions.
Well, I'll take a simple system, a single hydrogen atom, Even this is quite complicated.

So as I said, particles are caused when the fields get excited to some degree. Quantum mechanics and relativity demand these excitations be concentrated in small lumps called particles.

Now, for some fields another type of excitation is possible, extended excitations. These are dispersed over a wide area. In the case of the photon field, the particle excitations are photons and the extended excitations are electric and magnetic fields or a beam of light*. Now, there are several fields that cannot have extended excitations.

So, a given electron is an excitation of the electron field. Since the electron field and the photon field are coupled (can pass energy to eachother), the presence of an electron excites the photon field, creating one of these extended excitations, that we would recognise as an electric field.

Then, there are the eight gluon fields and six quark fields. It is impossible for these fields to become excited individually**. Only
excitations of all 14 similtaneously are possible. There are several different such possibilities, depending on the amount of energy in each of the 14 fields. However, of the hundreds of possibilities, only one is actually stable. This stable combination also takes very little energy to create, and hence is very common. We denote it the proton.

Hopefully the paragraph above gives some indication of how complicated the proton is, being a similtaneous excitation of 14 fields. For this reason there are several questions about its
structure and physics. One of the most poorly understood aspects of the proton is what is known as its "form factors", this is basically how the fields combine to give the proton a specific shape. LHCb is currently studying these properties of the proton, which will be particularly helpful for nuclear fusion.

Six of the fields associated with the proton are also coupled to the photon field, so the proton comes with an electric field as well.

Then, when an electron and proton come into contact with each other the electric field around both of them alters their dynamics. Essentially altering the probability field of the electron, so that it becomes vanishingly unlikely to be far away from the proton. This is a hydrogen atom.

So to recap, a hydrogen atom is a region of space at the center of which sits an excitation of 14 fields, known as a proton. This excitation disturbs the photon field, creating an extended excitation (commonly known as an electric field).
A nearby electron, an excitation of the Dirac field, interacts with this extended excitation, and gets its probability field altered so that it is no longer likely to be situated away from the proton.

*Contrary to popular explanations a beam of light is not made of photons/is a stream of photons any more than an electric field is. It's an extended excitation of the photon field.

**Sometimes it makes calculations simpler to imagine they can and we use fictional "quark particles". However at the current low tempertures of the universe none of these fields can be excited on their own, so no quarks currently exist. Also the proton is not made of quarks, despite what one will commonly see in texts.

Edited by Son Goku, : No reason given.


This message is a reply to:
 Message 165 by New Cat's Eye, posted 08-28-2013 9:31 AM New Cat's Eye has responded

Replies to this message:
 Message 173 by New Cat's Eye, posted 08-29-2013 9:25 AM Son Goku has responded

  
New Cat's Eye
Member
Posts: 11440
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 173 of 223 (705594)
08-29-2013 9:25 AM
Reply to: Message 172 by Son Goku
08-29-2013 5:31 AM


Re: Questions.
That is so awesome. Thanks again for taking the time to write it. It actually makes sense and I feel like I've got a lot more understanding now. It was neat to imagine it coming together from the other side... that is, rather than thinking from the macro level down into the individual atom and proton level.

I'll keep asking questions, but I'll understand if you don't bother answering them.

there are the eight gluon fields and six quark fields.

I realize that a 3D image of something like that isn't really a good idea, but how should I imagine these fields being in relation to each other? Like, are they wrapped up around each other, or would it be more like a lamellar structure or something?

*Contrary to popular explanations a beam of light is not made of photons/is a stream of photons any more than an electric field is. It's an extended excitation of the photon field.

I remember seeing the double-slit experiment in a physics lecture. (they even had a shallow water bath placed on an overhead projector with a little wave pusher so we could first see the constructive and destructive interference of the water waves... which was pretty sweet). Then they did it with a laser against the wall.

Anyways, for the light part of it, they said that there was an experiment with an emitter that emitted a single photon of light at a time, and then they go on to explain how the pattern still emerges. But what I don't get, now, is where the emission of a single photon, which QM+R demand be concentrated in small lumps, could also be an extended excitation?

Also the proton is not made of quarks, despite what one will commonly see in texts.

Being "made of" quarks was always something that didn't quite add up for me. The way you've explained it actually seems more intuitive to myself.

Hopefully the paragraph above gives some indication of how complicated the proton is, being a similtaneous excitation of 14 fields.

For sure. This universe is really freakin' weird. It can't believe it gets sooo complicated at such minute levels. You'd think it'd get simpler

Then, when an electron and proton come into contact with each other the electric field around both of them alters their dynamics. Essentially altering the probability field of the electron, so that it becomes vanishingly unlikely to be far away from the proton. This is a hydrogen atom.

Thanks again. You really nailed my question. I feel like I'm learning a lot.


This message is a reply to:
 Message 172 by Son Goku, posted 08-29-2013 5:31 AM Son Goku has responded

Replies to this message:
 Message 174 by Son Goku, posted 08-29-2013 12:23 PM New Cat's Eye has responded

  
Son Goku
Member
Posts: 1069
From: Ireland
Joined: 07-16-2005


(3)
Message 174 of 223 (705609)
08-29-2013 12:23 PM
Reply to: Message 173 by New Cat's Eye
08-29-2013 9:25 AM


Re: Questions.
I realize that a 3D image of something like that isn't really a good idea, but how should I imagine these fields being in relation to each other? Like, are they wrapped up around each other, or would it be more like a lamellar structure or something?

As you said, these things are flat out impossible to imagine. However, the closest macroscale system that quantum fields are similar to is a grid of springs, like you would find in a mattress.
Now, this is not something I'm making up, such a picture is given in a few graduate level textbooks (such as Anthony Zee's "QFT in a Nutshell").

So a given quark field is essentially like (in the sense of: this is the macroscale system it is most similar to) a vast system of springs filling all of spacetime. All six quark fields and eight gluon fields form a set of 14 mattress like layers filling spacetime.
In case this seems silly, look at the first page of these notes to see that this is the mental picture commonly used:
http://www.itp.phys.ethz.ch/...rchive/12HSQFT1/Chapter02.pdf

Now this mattress like layers of springs can be "plucked" setting up a travelling disturbance through them, which we would see as a particle. In the case of the quark and gluon fields it is impossible to have a single field excited. All fourteen layers will be disturbed simultaneously. However there is only one such disturbance which doesn't disperse, this is the proton. It is a travelling stable disturbance all fourteen layers.

You might also visually these disturbances as musical harmonies on fourteen separate drum-like membranes (the mathematics is quite similar). A sound on any of the membranes will produce a resonance on the other thirteen, they cannot vibrate alone. The proton is the only stable "musical note" that these fourteen membranes are capable of producing together.

Now again, I know it might seem stupid to use a mattress or a drum as an analogy, but if you take the mathematics of 4D set of springs or drum membranes add in quantum mechanics and take the limit as the springs get infinitely small, you literally get the mathematics of a quantum field. So this is "objectively" the best analogy. Particles are more mathematical similar to musical harmonies than any other macro-scale phenomena.

Anyways, for the light part of it, they said that there was an experiment with an emitter that emitted a single photon of light at a time, and then they go on to explain how the pattern still emerges. But what I don't get, now, is where the emission of a single photon, which QM+R demand be concentrated in small lumps, could also be an extended excitation?

The pattern actually isn't reproduced by a single photon. If you emit single photons, one after the other, they eventually (after a few million) build up the same pattern as a beam of light.

For sure. This universe is really freakin' weird. It can't believe it gets sooo complicated at such minute levels. You'd think it'd get simpler

Well to give you an idea, the first reasonably accurate simulation of a proton (the simulation ignored four of the six quark fields) in 2008, took IBM supercomputers hundreds of hours to complete. This was for a single proton. Now keep in mind that these same computers can simulate black hole collisions, the fluid dynamics of Boeing aircrafts and the collisions of galaxies in less than a tenth of the time the proton simulation took.
This message is a reply to:
 Message 173 by New Cat's Eye, posted 08-29-2013 9:25 AM New Cat's Eye has responded

Replies to this message:
 Message 175 by NosyNed, posted 08-29-2013 1:53 PM Son Goku has responded
 Message 176 by New Cat's Eye, posted 08-29-2013 2:29 PM Son Goku has responded
 Message 177 by NoNukes, posted 08-29-2013 10:39 PM Son Goku has responded
 Message 178 by Tanypteryx, posted 08-29-2013 11:22 PM Son Goku has not yet responded

  
NosyNed
Member
Posts: 8779
From: Canada
Joined: 04-04-2003
Member Rating: 4.3


Message 175 of 223 (705612)
08-29-2013 1:53 PM
Reply to: Message 174 by Son Goku
08-29-2013 12:23 PM


Thank you!
This is really interesting stuff! I was thinking about asking what it meant for a field to be "excited" but I think I have a finger nail grasp with the idea that the field vibrates like a drum head.

The "layers" is a bit of a problem for me. That makes my wee brain see things on top of and under each other. That seems to me to be a poor view. Is there another way to describe it?


This message is a reply to:
 Message 174 by Son Goku, posted 08-29-2013 12:23 PM Son Goku has responded

Replies to this message:
 Message 180 by Son Goku, posted 08-30-2013 5:31 AM NosyNed has not yet responded

  
New Cat's Eye
Member
Posts: 11440
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 176 of 223 (705613)
08-29-2013 2:29 PM
Reply to: Message 174 by Son Goku
08-29-2013 12:23 PM


Re: Questions.
s you said, these things are flat out impossible to imagine. However, the closest macroscale system that quantum fields are similar to is a grid of springs, like you would find in a mattress.

Alright, your description that follows makes a fair amount of sense.

All fourteen layers will be disturbed simultaneously. However there is only one such disturbance which doesn't disperse, this is the proton.

So for the disturbances that do disperse: Is that something that is happening all the time? If so, does it manifest itself in some way?

Now again, I know it might seem stupid to use a mattress or a drum as an analogy, but if you take the mathematics of 4D set of springs or drum membranes add in quantum mechanics and take the limit as the springs get infinitely small, you literally get the mathematics of a quantum field. So this is "objectively" the best analogy. Particles are more mathematical similar to musical harmonies than any other macro-scale phenomena.

That's really cool. I love reading this shit.

Anyways, for the light part of it, they said that there was an experiment with an emitter that emitted a single photon of light at a time, and then they go on to explain how the pattern still emerges. But what I don't get, now, is where the emission of a single photon, which QM+R demand be concentrated in small lumps, could also be an extended excitation?

The pattern actually isn't reproduced by a single photon. If you emit single photons, one after the other, they eventually (after a few million) build up the same pattern as a beam of light.

Oh, sure. I didn't mean to imply otherwise.

What I was questioning wass that, since QM+R demand the excitation be concentrated into small lumps (i.e. a photon) then how can a single photon emission also be an extended excitation (and thus exhibit the wave-like behavior needed to make the pattern)?

Well to give you an idea, the first reasonably accurate simulation of a proton (the simulation ignored four of the six quark fields) in 2008, took IBM supercomputers hundreds of hours to complete. This was for a single proton. Now keep in mind that these same computers can simulate black hole collisions, the fluid dynamics of Boeing aircrafts and the collisions of galaxies in less than a tenth of the time the proton simulation took.


This message is a reply to:
 Message 174 by Son Goku, posted 08-29-2013 12:23 PM Son Goku has responded

Replies to this message:
 Message 181 by Son Goku, posted 08-30-2013 6:22 AM New Cat's Eye has responded

  
NoNukes
Member
Posts: 9651
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.1


Message 177 of 223 (705621)
08-29-2013 10:39 PM
Reply to: Message 174 by Son Goku
08-29-2013 12:23 PM


Alleged flaws in GR
Son Goku,

I am particularly interested in the alleged flaws in GR that are described starting at the end of page 23 and continuing forward. In particular AB makes a number of what appear to me to be naked assumptions about GR errors, but I cannot discount the possibility that I simply cannot follow the paper.

For example, AB claims to have demonstrated that "the metric of space-time is of mathematical origin and plays no role in the physical structure of space" midway through the first column of page 24.

In the first column of page 25, AB alleges (essentially) that it is mere coincidence that the periastron advance of binary system PSR B1913+16 agrees with GR. He also argues that it is improbable that gravity waves have yet to be detected if they actually exist, whereas it is my understanding that most of the experiments performed so far have a low or zero probability for detecting gravity waves. AB seems to think that accumulating a bunch of zero or near zero experiments ought to add up to something fairly substantial, but the analysis looks simplistic to me.

Can you express an opinion re: these pages of AB's work?

Edited by NoNukes, : No reason given.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


This message is a reply to:
 Message 174 by Son Goku, posted 08-29-2013 12:23 PM Son Goku has responded

Replies to this message:
 Message 179 by Son Goku, posted 08-30-2013 5:04 AM NoNukes has acknowledged this reply

    
Tanypteryx
Member
Posts: 1471
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 4.8


Message 178 of 223 (705622)
08-29-2013 11:22 PM
Reply to: Message 174 by Son Goku
08-29-2013 12:23 PM


Re: Questions.
Son Goku, thank you so much! Your descriptions have have given me the first chance of mental images that I have ever had for how the universe is put together. Well done!!

What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy


This message is a reply to:
 Message 174 by Son Goku, posted 08-29-2013 12:23 PM Son Goku has not yet responded

    
Son Goku
Member
Posts: 1069
From: Ireland
Joined: 07-16-2005


Message 179 of 223 (705638)
08-30-2013 5:04 AM
Reply to: Message 177 by NoNukes
08-29-2013 10:39 PM


Re: Alleged flaws in GR
For example, AB claims to have demonstrated that "the metric of space-time is of mathematical origin and plays no role in the physical structure of space" midway through the first column of page 24.

It's just a statement, the alleged justification for it is a non sequitur proceeded by a description of GR that is incorrect.

He says:

Einsteins field equations apply quantized densities
in order to determine the curvature and metric of space-time.

Firstly quantised densities has no meaning as a phrase, I can only assume Alphabob means that GR requires mass to be concentrated at points (as he states previously) and not spread out continuously over an area. This is false, as GR can deal with both. For instance an introductory textbook like Schutz's "A first course in General Relativity" has students work out both cases in the exercises.

The real problem is the statement:

The second flaw is similar to the first, where
particles must exist as localized fields rather than
point-like objects. Similar to relativistic electro-
dynamics, the field of a particle becomes deformed
when the background vacuum energy density
varies.

Both of these statements are fine in a sense, the second is somewhat nonsensical. The energy of the vacuum never varies in the way he is imagining. However we'll leave this aside and just accept the two statements. We are then presented with this as the conclusion:

Therefore, the metric of space-time is of
mathematical origin and plays no role in the
physical structure of space.

If we put these two statements and the conclusion together, we have:
1. Particles must be somewhat spread out.
2. The field (I assume either their electric or probability fields, it's not clear which is meant) of a particle is deformed when the vacuum energy varies (unfortunately vacuum energy does not vary).

Then:
3. The spacetime metric (something unconnected to the objects discussed in 1. and 2.) is not physically real.

There is nothing to say really, it is a conclusion which doesn't follow from the two statements and one of these statements involves a process which doesn't occur.

He also argues that it is improbable that gravity waves have yet to be detected if they actually exist, whereas it is my understanding that most of the experiments performed so far have a low or zero probability for detecting gravity waves. AB seems to think that accumulating a bunch of zero or near zero experiments ought to add up to something fairly substantial, but the analysis looks simplistic to me.

It's just nonsensical. General Relativity predicts that it would be quite unlikely that these detectors would see gravitational waves.
So currently, we cannot accept or reject the predictions of GR over the null hypothesis of no gravtiational waves. The equipment currently isn't sensitive enough. No amount of statistics can tell you anything if it is simply based on null results from equipment that should produce null results under both scenarios. This of course, is what you said yourself.
This message is a reply to:
 Message 177 by NoNukes, posted 08-29-2013 10:39 PM NoNukes has acknowledged this reply

  
Son Goku
Member
Posts: 1069
From: Ireland
Joined: 07-16-2005


Message 180 of 223 (705639)
08-30-2013 5:31 AM
Reply to: Message 175 by NosyNed
08-29-2013 1:53 PM


Re: Thank you!
In the mattress analogy, a single quantum field consists of a set of points with a set of springs connecting them, as shown in the pdf I linked to.

Another quantum field is simply a second set of springs connected to the same set of points. We can take the simplest picture of the Higgs field and the photon field. Both are sets of springs attached to points in spacetime. Imagine the Higgs field as red springs, photon field as black springs (or however you want to distinguish them, that's just one I sometimes use.) Then a Higgs particle is a vibration travelling along the red springs. When the vibration reaches one of the points there is a probability (this is where quantum mechanics is involved) that the vibration will be passed on to the black springs (photon field). This is would appear as a Higgs particle decaying into two photons.

Again from Anthony Zee (lecturer at Univerity of California, Santa Barbra), "Quantum Field Theory in a Nutshell" (a graduate textbook), Chapter 1.3, p.20:

We would like to create a particle and watch it propogate for a while....To see how to do this, let us go back to the mattress. Bounce up and down on it, to create some excitations.......By bouncing up and down on the mattress we get wave packets (Son Goku: this means harmonic vibrations in the mattress) going off here and there....this corresponds precisely to [particles]

This message is a reply to:
 Message 175 by NosyNed, posted 08-29-2013 1:53 PM NosyNed has not yet responded

  
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