Welcome to
Science a GoGo's
Discussion Forums
Please keep your postings on-topic or they will be moved to a galaxy far, far away.
Your use of this forum indicates your agreement to our terms of use.
So that we remain spam-free, please note that all posts by new users are moderated.


The Forums
General Science Talk        Not-Quite-Science        Climate Change Discussion        Physics Forum        Science Fiction

Who's Online
0 registered (), 349 Guests and 0 Spiders online.
Key: Admin, Global Mod, Mod
Latest Posts
Top Posters (30 Days)
Page 2 of 2 < 1 2
Topic Options
#41413 - 11/12/11 05:12 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
"Unenergized empty space"

Is that space full of "stuff", virtual "stuff" and energy (virtual or otherwise)that is simply in the lowest possible energy state?

At the boundaries, does it interact with the universes?
_________________________
There never was nothing.

Top
.
#41414 - 11/12/11 05:18 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Originally Posted By: O
QM basicly saying the universe is a whole lot bigger and weirder than science had it.


The more I read of what QM is saying about the Universe, the more I think I should like it.
_________________________
There never was nothing.

Top
#41416 - 11/12/11 06:55 PM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Originally Posted By: Bill S.
"Unenergized empty space"

Is that space full of "stuff", virtual "stuff" and energy (virtual or otherwise)that is simply in the lowest possible energy state?

At the boundaries, does it interact with the universes?


Remember this one of of many theories in QM but it is the one most relevant to this discussion. The others are Quantum loop theories and string theories.

In this unruh version the unenergised space is simply space at the lowest possible energy state. The universe event front represents the wavefront of it being charged up to a vacuum state as we see it.

One way to visualize it get a big dry sponge then drop a coloured liquid drop in the midle and watch it spread out.

At the boundary the Quantum field energy is continually charging up new new space as it races out.


Edited by Orac (11/12/11 06:56 PM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41417 - 11/12/11 06:57 PM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Originally Posted By: Bill S.
Originally Posted By: O
There could actually be a universe next door expanding like us and eventually we will collide.


Does QM make any proposals as to what the nature of the "space" between these universes be?


Exactly whatever our space is made of minus the quantum fields.
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41419 - 11/12/11 07:41 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
So all the Pop Sci books that tell us that the Universe is not expanding into anything are either behind the times, or following a different theory in a sort of "anything goes" scientific jungle.

Go for it, Finiter! Even if Orac is right in this Universe, there's going to be one out there in which you will have the last laugh. laugh
_________________________
There never was nothing.

Top
#41421 - 11/13/11 02:16 AM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Science is a progression based on new observation.

I sort of cringe at theories of the seventies era and I note string and quantum loop theorists are now sort of laughed at called stringies and loopies.

When everett proposed the multiverse it was howled at and then became mainstream almost.

This is just another in a long line of theories it will take but one inconsistant observation to kill it, something that finiter won't accept and why his theory isn't science.

The current phase space QM theory currently has no inconsistancies and it has a number of predictions on the table the failure of anyone of them and the theory falls.

I like its elegant symplicity but that is often a death kiss as with the Higgs mechanism simplicity is not a criteria for nature.

The next two years will make or break phase space there are a number of important tests set to happen on which the theory will pass or faulter and die.

Meanwhile I look forward to mondays conference announcements which I will report in as soon as I hear.
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41422 - 11/13/11 03:39 AM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
gan Offline
Member

Registered: 07/21/10
Posts: 55
QM really makes me confused. Classical Theories gone wrong in QM. I want to ask, why phase factor=e^(kx-wt+phi) ? The induction of Schrodinger's equation is easy. but where is this e^(kx-wt+phi) come from?

Momentum is proportional to frequency. p=hf
Can we measure motion which smaller than h-bar? and now, why is h-bar?

Top
#41424 - 11/13/11 04:28 AM Re: Question to Physics experts Re: Light & Space [Re: gan]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Originally Posted By: gan
QM really makes me confused. Classical Theories gone wrong in QM.


That is because we believe classical theories were always wrong. People thought the world was flat because thats what you see, until you can circum-navigate it and make other key observations then you realize it isn't flat.

Perception is everything to us and we most easily decieve ourselves.

Originally Posted By: gan

I want to ask, why phase factor=e^(kx-wt+phi) ? The induction of Schrodinger's equation is easy. but where is this e^(kx-wt+phi) come from?


It comes from the premise that phase space has that there are two and exactly two positions for matter in the universe created by two waves in superposition. Unlike Everetts multiverse where there are many universes phase space has only two so when something is in superposition it is oscillating between them.

Look at the formulation of two standing waves beating against each other (http://www.kettering.edu/physics/drussell/Demos/superposition/superposition.html)

See superposition is not unique to QM it's a behaviour of any normal waves.

So the derivation of that formula describes two wave spaces in superposition beating against each other.

This one is an overview that is reasonably old it still shows compatability of the theory with other theories like SUSY but it will give you an feel for the subject because it's reasonable simple presentation

http://www.lpt.ens.fr/IMG/pdf/Bars.pdf

It all sounds weird until you realize that you need this sort of mathematics for describing movement in an ocean because you have wind and tide motions which create standing waves.

If you tried to describe motion on an ocean with no global reference, so you are at sea no GPS no sign of land how do you describe your motion? You can only do it realive to things around you like a log on the water etc. But you have a huge problem don't you because you realize that you must be drifting but without reference how do you calculate that, think about what your world looks like.

I am sure sailors who have been lost at sea could describe the world very well for you. See phase space is not so strange if you are far out at sea with no GPS :-)

Quote:

Momentum is proportional to frequency. p=hf
Can we measure motion which smaller than h-bar? and now, why is h-bar?


You can not measure anything smaller than the smallest beat between the two wave spaces which becomes your plank constants. Thats another strength of the theory it explains why plank distance, plank time etc exist. And that explains your question if you follow the extraction of formulas out.

Phase space is not going to be like string theory hang around for a longtime if it's wrong because it makes alot of predictions it will die very fast if wrong.


Edited by Orac (11/13/11 04:52 AM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41426 - 11/13/11 05:03 AM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
gan Offline
Member

Registered: 07/21/10
Posts: 55
Wow! And now can explain me the Hermitian operator ?

Top
#41431 - 11/13/11 03:42 PM Re: Question to Physics experts Re: Light & Space [Re: gan]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
I think you mean Hamiltonian operator gan and this is probably going to get way outside you understanding at a full level unless you have exceptional mathematics.

So lets se if I can simplify this ... I am going to take some liberties here so you can follow so this is a layman approximation.

Essentially the hamiltonian is going to going to be the sum of the kinetic and potential energies which is all reasonably easy in our normal classical world.

I have taken a liberty here in that we have to assume the system is closed and speeds and acceleration are not relativistic so we don't need to consider special relativy time effects.

So the Hamiltonian operator would describe the movement of energy across time.

All of your normal classical motion laws can be described by hamiltonian operators.

If you look at a normal orbital of a planet around the sun you are probably aware the planet goes fast near the sun and slows down as it goes away. There is kinetic energy and gravitational potential energy exchanging backwards and forwards and the planet has a total energy (see this example of the working http://www.arachnoid.com/gravitation_equations/orbital_mechanics.html)

In that sample the combined energy I could rewrite the energy with respect to time of the planets position relative to the sun. Lets say I chose the position closest to the sun and called it time t = 0. I could then rewrite the energy with respect to that time and position as an equation and that would be a simple Hamiltonian operator.

Why are they useful? we already have the laws of motion and could calculate everything anyhow. That is true but say I gave you two orbiting planets at 90 degrees to each other, how do I calculate if and when the two planets will collide.

What the hamiltonian operator form of the orbitals will allowed you to do is solve for time the planets collide.

What happens if another sun drifts in and makes our sun bigger over a period of 20 years, okay it can't happen but you get the idea. What is happening is we need a way to change the energy in the system slowly over time so it correctly portraits the situation. Your classic laws assume things are fixed not evolving over time and at any point you calculate them they will be only correct for one point in time if the system is evolving.

In cosmology and QM hamiltonian operators describe how things partiles, planets, balls, objects or you and me whatever exchange energy over time.

If you want to know more it's probably best you do some reading because some of these details I find extremely difficult to simplify especially with English being my second well third language :-)


Edited by Orac (11/13/11 03:45 PM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41432 - 11/13/11 03:46 PM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
finiter Offline
Senior Member

Registered: 08/15/11
Posts: 211
Originally Posted By: Bill S.

Go for it, Finiter! Even if Orac is right in this Universe, there's going to be one out there in which you will have the last laugh.

No, nothing short of this 'very universe of ours' will do. If Orac is willing, let him take one of the others.

Top
#41434 - 11/13/11 04:06 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
gan Offline
Member

Registered: 07/21/10
Posts: 55
I mean Hermitian operator. Yeah, I know Hamiltonian mechanics well smile

Top
#41437 - 11/13/11 05:10 PM Re: Question to Physics experts Re: Light & Space [Re: gan]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
This is going to get very involved and very maths abstract gan :-)

You will need to give me some background do you know about matrix mathematics and hermite curves in you want to go deeper than what I am about to do for simplicity?

So you have your hamiltonian operator which is how your systems is evolving over time, which you understand.

Since by definition your hamiltonian has the dimension of energy then if we are describing that system from a waveform input as in QM (schrodinger wave equation) then we can describe your hamiltonian via a matrix calculation and that matrix eigenvalues are real.

Essentially what we are saying is we can tie the movement of our input waveforms through to your hamiltonian system.

Many matrix solutions provide non real solutions so your hamiltonian will work when we look at a static value but it will not play out in the correct order if we looked at it over time. So given a wave input your hamiltonian values would plot to some correct value but when we slowly move the input wave the output would jump all over the place to a value on our output but the time sequence would be all wrong.

A hermitian operator is a solution from your input waveform to your hamiltonian system so it is time consistant or smooth as opposed to one that jumps around all over the place.

I guess if you imagine a joystick as your waveform input connected thru your computer to some machine. If you imagine the joystick has 256 positions what you want is a fluent movement not the 256 positions being represented all weirdly on the machine so it jumped around all over the place. Such a nice mapping I would call hermitian in operation.

In QM all observable properties must be represented by hermitian operators as we don't see balls jumping from one location to another then back they move fluently.

The reason for that requirement is the mathematics will give you many solutions but many will be of that jumpy, jerky type which are not hermitian.

The background of this sort of movement is hermite curves and hence the expression.

So hermitian operators are what we would call possible real world solutions there will be many other jerky, disjointed solutions.

I have taken a few liberties again because this is very difficult to bring down to this sort of level.


Edited by Orac (11/13/11 05:13 PM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41439 - 11/13/11 06:48 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Revlgking Offline
Megastar

Registered: 01/17/07
Posts: 2311
Loc: markham (Thornhill), Ontario, ...
Now, the following makes sense to me:

http://en.wikipedia.org/wiki/Charles_Hermite

So, what is the practical value of hermite curves?
==================
I have no idea the meaning of the following, but it does show what the curves look like:
http://en.wikipedia.org/wiki/Cubic_Hermite_spline

http://www.cubic.org/docs/hermite.htm
_________________________
G~O~D--Now & ForeverIS:Nature, Nurture & PNEUMA-ture, Thanks to Warren Farr&ME AT www.unitheist.org

Top
#41441 - 11/13/11 07:12 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
From my point of view, that was a fortunate misunderstanding. I almost understand hamiltonian operators now - almost. smile

Thanks Orac.
_________________________
There never was nothing.

Top
#41445 - 11/14/11 02:13 AM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
Yes I wasn't expecting a 15 year to understand hamiltonian operators either Bill S ... I couldn't even imagine he would have run across hermite continuity conditions.

Our Gan is very gifted ... watch out :-)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41448 - 11/14/11 03:26 AM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
gan Offline
Member

Registered: 07/21/10
Posts: 55
thx for the praise. I am not gifted, but I have a well basic on maths. I can just run through and understand all the mathematical abstract formulas. Like Hamiltonian operators and Hermition Operator. Thx Orac. You really solve many of my difficulties on "non-maths" in Hermition Operator.

http://www.cubic.org/docs/hermite.htm
this describe well.. Thx Revlgking. And my last question smile

I have some problems on bra-ket vector.
alpha lA> + beta lB> = lZ>
<ZlZ>=alpha alpha* + beta beta* + alpha* beta <AlB> + alpha beta* <BlA>
And the probability should added up and equals to 1. So
<ZlZ> = 1
And now,
alpha alpha* + beta beta* = 1
<AlB> and <BlA> = 0 am I right?

Top
#41508 - 11/17/11 11:03 AM Re: Question to Physics experts Re: Light & Space [Re: gan]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
This ones for you Gan.

Thats the new unifying Quantum theory that everyone has been excited about

http://www.nature.com/news/proof-found-for-unifying-quantum-principle-1.9352

Don't ask me to explain it .. I can't sorry way to complex mathematics.

The paper is in the references if you think you are up to it.
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#41515 - 11/17/11 04:00 PM Re: Question to Physics experts Re: Light & Space [Re: SWMayers]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Quote:
When John Cardy proposed a far-reaching principle to constrain all possible theories of quantum particles and fields1, he expected it to be quickly rebutted.


If Cardy had been posting this in SAGG, should it have been in Physics or NQS?
_________________________
There never was nothing.

Top
#41521 - 11/18/11 01:00 AM Re: Question to Physics experts Re: Light & Space [Re: Bill S.]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
It's science Bill because it extends things.

The rules for science theories are really simple there are exactly two

Here is the reference (http://en.wikipedia.org/wiki/Scientific_theory)

Look at Essential criteria there are two rules:

1.) It is consistent with pre-existing theory, to the extent the pre-existing theory was experimentally verified, though it will often show pre-existing theory to be wrong in an exact sense.

2.) It is supported by many strands of evidence, rather than a single foundation, ensuring it is probably a good approximation, if not totally correct.


Those two rules are set in stone by all science organisation because of what they do, expand science ever outwards.

Intelligent Design, PreEarths theory and Finiters Theory may meet essential criteria 2, we would have to look at that as a seperate issue.

However they all fail criteria 1. The net effect of failing criteria one is we would be contracting science, stuff that is currently explainable and calculatable suddenly isn't accepted or explainable?????.

Science does not allow itself to go backwards it is the number 1 rule and not open for discussion.

Lets take a wild leap Intelligent Design, Finiters and Preearth theories basis behind there theory could even be correct. They can't be totally correct because they can't explain some observations. So science simple sides on the one that can explain more.

Thus Intelligent Design, PreEarths theory and Finiters theory may be limitedly correct (although I really doubt all 3 as we haven't applied test 2 yet). They still are not scientific and can not be taught as science because they create contraction in knowledge. There job if they want to become science is to expand out and extend science.

If you like many theories are born non scientific and only when they expand out to meet and expand science can they become scientific.

We can even have scientific discussions about ideas in Intelligent Design, Finiters Theory and PreEarth theories and in general any new theory goes through that process.

They cross the line when they try and say they are scientific what they have breached in doing that is rule 1 of scientific theories.

Go back to the finiter thread

Finiter => I have a theory about the universe.
Science => absolutely no problem there, shoot.
Finiter => QM doesn't exist.
Science => Umm ok so what explains all the QM stuff
Finiter => I don't know some alternate explaination someone will work it out
Science => ummm ok so this isn't a science theory then.
Finiter => Yes it is now lets talk about the definition of science.
Science => Umm no not up to you and I to define science

Finiters theories problem is it denies QM and does not fix the observations and calculations it can never become science it is in the same boat as Intelligent Design.

Now go back up to the article above from John Cardy he created a scientific theory. It was always a scientific theory because it expanded science outwards. All current observations still work under the new theory so the only question that then remained was does it add in new observations to prove itself. It does so it can overturn the old theory because it explains all the current observations and adds new ones in .. that is it expands science.

So whenever you look at a theory ask yourself does this expand our knowledge, if yes then it is scientific, no it contracts it then that theory is not scientific. Remembering here we are assuming we have observations and experiments to verify it is true, it can't be just made up.


Edited by Orac (11/18/11 05:56 AM)
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
Page 2 of 2 < 1 2



Newest Members
debbieevans, bkhj, jackk, Johnmattison, RacerGT
865 Registered Users
Sponsor
Facebook

We're on Facebook
Join Our Group

Science a GoGo's Home Page | Terms of Use | Privacy Policy | Contact Us
Features | News | Books | Physics | Space | Climate Change | Health | Technology | Natural World

Copyright © 1998 - 2016 Science a GoGo and its licensors. All rights reserved.