Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thebrain13 on 30/03/2011 05:11:18
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In chemistry we learned, E=hν which means energy equals planks constant times frequency. Our professor (and our book) then suggests that this means that energy can only exist in certain quantized amounts that are integers of planks constant. Is this true? The way I see it, assuming this equation is correct (which I am) this in no way suggests that electromagnetic energy is quantized. because ν, frequency, is not an integer. It can be any possible value, and any possible value times a constant can be anything. And if energy can be anything, that is the opposite of quantized. But that is not at all how it is being represented to us in class or in our literature. Am I missing something?
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In chemistry we learned, E=hν which means energy equals planks constant times frequency. Our professor (and our book) then suggests that this means that energy can only exist in certain quantized amounts that are integers of planks constant. Is this true? The way I see it, assuming this equation is correct (which I am) this in no way suggests that electromagnetic energy is quantized. because ν, frequency, is not an integer. It can be any possible value, and any possible value times a constant can be anything. And if energy can be anything, that is the opposite of quantized. But that is not at all how it is being represented to us in class or in our literature. Am I missing something?
I'm no expert in this field, so someone will point out if this is wrong, but perhaps if you consider the wavelength rather than the frequency, the quantization aspect will become more apparent. I'm assuming there is some connection between integer wave cycles and quantization, but that may well be baloney!
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In chemistry we learned, E=hν which means energy equals planks constant times frequency. Our professor (and our book) then suggests that this means that energy can only exist in certain quantized amounts that are integers of planks constant. Is this true? The way I see it, assuming this equation is correct (which I am) this in no way suggests that electromagnetic energy is quantized. because ν, frequency, is not an integer. It can be any possible value, and any possible value times a constant can be anything. And if energy can be anything, that is the opposite of quantized. But that is not at all how it is being represented to us in class or in our literature. Am I missing something?
EM energy is quantized *fixing the frequency*. If frequency is free, then you can have whatever energy you want.
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Well Geezer, wavelength is completely dependent on frequency given the equation ν=c/λ with ν as frequency and λ as wavelength, so if frequency can be anything so can wavelength.
And lightarrow, if you "fix the frequency" you dont get quantized EM levels, you get the same exact energy every time!!! The only thing that determines the energy of a photon is its frequency. Unless you fix the frequency to equal quantized energy levels, you don't get quantized energy levels.
Okay let me give you guys a few quotes from my book, "Einstein deduced that each photon must have an energy equal to plancks constant times the frequency of the light: E=hv Thus radiant energy is quantized". How are they making that logic jump?
"According to Plancks theory, matter is allowed to emit and absorb energy only in whole-number multiples of hv, such as 1hv, 2hv, 3hv, and so forth. If the quantity of energy emitted by an atom is 3hv, for example, we say that three quanta of energy have been emitted. Because the energy can be released only in specific amounts, we say that the allowed energies are quantized, their values are restricted to certain quantities."
I don't understand this at all, how much energy is 1 quanta? hv can equal anything. And since the only thing that determines the energy of a photon is its frequency, once the frequency is known, how would it make any sense to multiply it be integers of 2 or 3 or whatever? there is no such thing as a double electron or a triple electron that has higher energy with the same frequency, so what are they talking about?
To me it seems like people are just going out of their way to make things "quantumy".
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If frequency is quantized how small would the quanta be in the HF radio range.
Digital frequency synthesisers do in fact create at sort of quantization depending on the resolution of the electronics, how does this compare to a Planck's constant resolution.
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And lightarrow, if you "fix the frequency" you dont get quantized EM levels, you get the same exact energy every time!!!
No. If I send you 1 photon of frequency f, you get the energy E = h*f. If I send you N photons, you get N*E energy.
"Quantized EM energy" means that, and nothing else.
You can have only integer values of the unit of energy E. You cannot have 1.23E or ½E, ecc.
Of course we are still talking of fixed frequency.
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If frequency is quantized how small would the quanta be in the HF radio range.
I believe you are able to make that simple computation, but in case you don't want to, tell me the frequncy and I'll multiply it by h. [;)]
Digital frequency synthesisers do in fact create at sort of quantization depending on the resolution of the electronics
What does it mean?
how does this compare to a Planck's constant resolution.
after have explained the concept up, give a numerical value.
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Energy can only be emitted or absorbed in specific quantities, but it can exist at any quantity.
The energy difference between two orbitals is a fixed amount. I believe this is due to the "fact" (new theory) that every species of particle is a strange attractor in the chaotic mix of regular energy and dark energy. So you can only have transitions from one strange attractor to another strange attractor.
Once a photon is emitted into the vastness of empty space, it gradually becomes redshifted by the expansion of space, so it's energy changes continuously, rather than in discrete jumps. There is also the matter of Doppler shift, time dilation and length contraction between moving reference frames. If time and distance are not quantized, then neither is velocity or energy. The quanta of time and distance, if they exist, must be near the Planck scale, so they can never be measured or even detected.
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If I make a digital frequency synthesiser generating a frequency of about 10 MHz is the smallness of the frequency increments that I can generate limited by the precision of the electronics or is there some more fundamental limitation.
I am assuming that all correspondent are familiar with the design of digital frequency synthesisers
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Yes. A single photon has a certain amount of energy, and that energy is a function of the particular frequency. What I was getting at is that I suspect there is a connection between that amount of energy, and the length of a single cycle of a wave. You can't have one and a bit cycles, if you see what I mean. Of course, I'm willing to believe that it's nothing to do with that at all! [:D]
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Yes. A single photon has a certain amount of energy, and that energy is a function of the particular frequency. What I was getting at is that I suspect there is a connection between that amount of energy, and the length of a single cycle of a wave. You can't have one and a bit cycles, if you see what I mean. Of course, I'm willing to believe that it's nothing to do with that at all! [:D]
It depends on the physical situation doing the quantization. If you're in an absorbing cavity (a model for the black body radiator), then the only waves which can exist in it are those which are zero at the boundary, i.e. you can squeeze a half-integer number of wavelengths into the cavity.
Photons are nastier beasts, so you can't really talk about classical wavelengths being squeezed into a photon, since photons don't have a nice simple description as a wave function over a region of space.
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"how much energy is 1 quanta?"
Sweet question. If we go after red and blue shift then the energy in a photon has to be a relation to the observer. The next question I have would be if photons can come intrinsically in different 'energies', and that they seem to do as proved by the black body radiation (Planck) and photoelectric effect (Einstein). The next question would be how that energy is 'deployed'? And there it seems as if they looked at waves and then, with Einstein redefining those waves bouncing as photons, they just translated the frequency observed, into the photons energy? Planck was the guy finding that that radiation from a oven (temperature) only made sense when he assumed that the energy of a vibrating molecule was 'quantized' into certain steps, 'jumping' from one energy, or as he saw it frequency, to another. Physicists used that idea a long time thinking of it as a mathematical 'trick'
"The energy would have to be proportional to the frequency of vibration, and it seemed to come in little "chunks" of the frequency multiplied by a certain constant. This constant came to be known as Planck's constant, or h"
He must have been an awesome mathematician Planck. Then Einstein came along proposing that light was particles, or quanta, that he called photons (not really him, sorry. It was Gilbert Lewis that coined the word photon to express a quantum of light, 1926. The two words used differently in different situations making me for the longest time to consider them as being 'different':), having a energy of Planck's constant, times its frequency.
So I guess it all came from looking at it as waves, or frequency's, that would make the translation into 'quanta' a natural step once one accepted Einsteins ideas of 'photons'. But it would have been so much easier (for me) to expect a 'quanta' to just be of one 'energy' I think. As it is you have different 'photons' with different 'energies', all getting red and blue shifted. And translating a stream of waves into photons', depending on how many there are per 'time unit', as measured at some point, makes no sense to me when considering a expansion for example. There it only makes sense when thinking of it as waves. :)
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My possibly erroneous arithmetic calculates that the wavelength of the highest energy gamma rays observed i.e 10^20 ev is equivalent to .3*10^-25 meters, assuming that the smallest unit of length is that postulated by Planck i.e 1.6*10^-35 m it would seem that no quantization of energy would be observable although it may have been at the time of the BB.
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What defines the possibly fundamental 'sizes' making sense is Planck units. "Originally proposed in 1899 by German physicist Max Planck, these units are also known as natural units because the origin of their definition comes only from properties of nature and not from any human construct. Planck units are only one system of natural units among other systems, but are considered unique in that these units are not based on properties of any prototype object, or particle (that would be arbitrarily chosen) but are based only on properties of free space." From H e r e. (http://en.wikipedia.org/wiki/Planck_units)
"I have always felt that Planck units are trying to tell us something fundamental but that view is often undermined by frequent mentions that are is nothing physical or fundamental about the Planck length. In other words the Planck length does not represent a minimum distance. It is easy to see how a discrete Planckian coordinate system falls apart. Imagine a grid of coordinates of based on units of one Planck length. A diagonal can not be made of a whole number of units. The circumference of a circle with radius of one Planck unit is not a whole number of Planck units. Even if we "square off" a circle at the Planck scale to give it a "circumference" of 4 Planck units the diagonals are no longer a whole number. One way out of this dilemma is to forget about the discreteness of distance at the Planck scale and consider the Planck unit of time or its inverse (frequency) as being the more fundamental minimum unit. With time as the discrete unit the problem of Planck circles or diagonals disappears if no longer insist on distance as being discrete. The wavelength of a photon still comes in discrete units of Planck length but that is side effect that is completely determined by the discreteness of time and the constancy of the speed of light. Knowing the frequency of a photon (which is always a discrete inverse multiple of time units) determines the discreteness of its other physical qualities such as energy and momentum. You can also think of the temperature and mass of a Planckian black hole in terms of a characteristic frequency."
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So if you mean that those might define 'SpaceTime' as from measurements I agree.
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This is my whole point. Energy is not quantized. Yes, energy is carried around by particles, but the particles can have any energy. A photon can carry any amount of energy as long as it isn't an amount that makes it turn into something else. My professor and I'm sure most others are trying to convince people otherwise. and the reason they do it is because quantum mechanics is popular, and the idea that everything has to be quantized fits most peoples notions of modern day science. Everybody in my class who was listening now thinks that photons can only carry certain amounts of energy because of planks constant. Everybody now thinks that an individual photon can only carry with it 1e 2e 3e and so forth and that 1.5 e is impossible. That is what is being taught, and that is not what is supported by experimentation.
And yes lightarrow, energy would be quantized if frequency were fixed, but its not, so it isn't. That's my whole point.
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Now, that one you need to expand on Brain?
'Something else' you write?
Spontaneous pair production?
And do you see the energy as being undefined until the interaction? How about the photoelectric effect?
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well if you applied enough energy to a photon, it could become an electron/positron pair. I want to say an electron and a positron are .511 mev. dont quote me on it, but if a photon carried that much energy x 2 (since it needs to create a pair) I think it would just convert.
regardless of that, it doesn't really contribute to my topic though.
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It's interesting. Why don't you open a topic in 'New Theories' and describe what you are thinking of in detail? I'm not sure how it can have 'any energy' at the same time as we see it act inside certain 'energy jumps'. Then again, I assume virtual photons and 'real' photons to be the same :) But there I lean on HUP. But open a topic there, I promise you that I will read it with interest.
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See here's the thing, it's not a new theory. A photon can carry an energy of pretty much any value, not only quantized jumps of energy. I think its ridiculous that college students are being taught otherwise.
It speaks to a major problem science has as a whole. The problem is that science moves with the opinions of "everybody in aggregate", that is what people want to teach or talk about is what ultimately becomes mainstream science. For example, consider the experiment known as superfluidity. Most people have no idea what that is. If you type that name in this box, it will be underlined in red for not being a real word. If you don't know what it is, look it up and watch a video of it. It will blow your mind, if they showed this experiment to students they would be shocked and amazed. The first video I saw of it was in black and white from the 50's or something. So its not new.
So the question becomes: why does nobody seem to know about it? I think the answer is because its so counter-intuitive. Nobody, particularly professors, want to "explain" things to a group of people that they cant explain. If that makes sense, people like to talk about things that go along with their pre-conceived notions, superfluidity doesn't go along with anybodys pre-conceived notions, including my own. I wouldn't even know where to start with something like that. But that's the thing, professors wouldn't want to teach it to their students, so it basically flys under the radar and ultimately gets ignored. If superfluidity could be explained using some brand new theory, I'm willing to bet it would gain fame quite quickly.
Superfluidity has the problem that it seems to violate many laws, particularly perpetual motion. In the video I saw, they had a fountain. With a superfluid, if you start a fountain, it never stops!!! You did not mis-read me. Look it up. Its got a bunch of other really unusual characteristics, that seem to not be related with anything. Superfluids create way more questions than they answer and thats why its ignored. When you think about it, all the experiments you do in lab, are based off the theories you learn in class. So the experiments based on theories you don't learn about in class, get ignored.
Heres another example. Bose-novas. What this is, is an experiment where under certain conditions, exactly one half of the mass in the experiment disappears. However, very little energy is released under the reaction. Where does half the mass go? Nobody knows. It seems to fly right in the face of conservation of mass and E=mc^2. Nobody can explain it, it flys in the face of what is already accepted, if this cant disprove conservation of mass, what can? science cant just change directions on a dime, so what happens is the experiment becomes largely ignored.
Quantum mechanics works just like this, it follows the biases of the people as a whole. Go to any book store (at least in the U.S.) and look at the selection, its always about quantum mechanics and string theory(which has a bunch of similar themes) Very few science books would completely omit q.m. The history channel will talk about it. Teachers will talk about it. My chem book, calls it "the theory of the future". The public funding is largely aimed at it. If somebody is trying to impress you with their science knowledge they'll talk about. They'll say "quantum, blah blah blah, determinism blah blah blah, probability blah blah blah, mechanics blah blah blah" just cause it sounds good. (I am picturing a real life encounter with that example, not just forums) Nobody "really" gets it, nobody's an "expert" that's why it sounds so good.
I guess my point is, it's so accepted, that they are now teaching us false things in school just to try to make it more compatible with their favorite theory. It's not really anybodys fault, it isn't intentional, it's just when everyone has the same bias, the accepted "norm" only naturally will follow.
Photons can have any "reasonable" energy. They can be anything, the exact opposite of quantization.
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See here's the thing, it's not a new theory. A photon can carry an energy of pretty much any value, not only quantized jumps of energy. I think its ridiculous that college students are being taught otherwise.
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Photons can have any "reasonable" energy. They can be anything, the exact opposite of quantization.
Photons can have any energy, including some very unreasonable ones! Of course, once you've picked an energy, you've picked a frequency, and once you've picked a frequency, that frequency gives you minimal packets of energy. This has been checked by experiment, so there's not really a question here.
As for your rant against mainstream physics, plenty of people know exactly what they're talking about with quantum mechanics. Just because you don't like or understand it doesn't mean it's wrong.
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I really liked the tip you gave on Bosenova. (http://en.wikipedia.org/wiki/Bosenova) Very interesting indeed. As for superfluidity I knew some of it. When you say they can't explain it I'm not sure. There are some really weird effects in a chilled Bose Einstein condensate. But your fountain will only exist as long as the Helium4 is chilled near absolute zero. So it takes 'energy' to create and maintain it.
"Further studies showed that this superfluid, now called Helium II, behaved as a two-fluid model, partly in a low energy ground state, and partly in an excited state. With a little added heat and manipulation of the superfluid, an interaction of the two states was enhanced, producing a fountain effect, as though 2 fluids existed.
In our own Sun and countless other stars, hydrogen fusion produces helium, the second most abundant element, and is in turn eventually fused by steps into carbon-12. On Earth there isn’t much, a trace atmospheric gas but found in quantity up to 7 percent in some natural gas. It’s produced by nuclear decay, as from radium and polonium, dangerous alpha radiation releasing, in fact bare nuclei of helium that eventually pick up electrons and form stable helium isotopes.
Given an electric charge, helium can fluoresce like neon. Even rarer molecules of helium-3 have been produced in helium-4 during ionization. Superfluid helium is also a superconductor, 30 times more efficient than copper as well as a thermal conductor 300 times that of copper. And both helium-3 and helium-4 have been cooled to near absolute zero, helium-4 retaining its superfluidity, helium-3 crystallizing, yet still capable of movement like other BECs. Adding enormous pressure of 25 atmospheres and more, forces even helium-4 to act like other BEC ‘solids’." From Here.. (http://bigsciencenews.blogspot.com/2008/07/superfluids-becs-and-bosenovas-ultimate.html)
It's very weird effects creating a lot of questions.
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Here's a discussion on bosenova's taken from the Large Hadron Collider Safety Facts (http://www.lhcfacts.org/?tag=bosenova)
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"There is a remarkable amount of incorrect information and claims made about Bose Einstein condensation (BEC) and the Bosenova in the above discussion.
As the person who supervised the Bosenova work, as well as participating in creation of the first BEC in a gas, I can state ABSOLUTELY CATEGORICALLY that it is totally inconceivable that a black hole could be produced by these phenomena. To even suggest the possibility of such a thing demonstrates not just a terrible ignorance of physics but a basic lack of understanding of numbers. A BEC is literally many many billions of times farther from the conditions needed to create a black hole than is the paper clip sitting on your desk. The condition required to create a black hole is enormously high density. A BEC is vastly less dense than a paper clip and even many thousands of times less dense then the air in the room. The laws of physics and all the experimental data shows that when we try to make a BEC even a little denser, it simply reverts to ordinary cold low density gas atoms. In the Bosenova, the BEC is seen to get slightly denser than a regular BEC for a brief time, but it still remains thousands of times less dense than regular air. Further studies have also shown us where the “missing” atoms went. They turned into rather mundane molecules and so we could not see them in the way we were looking.
If you want something to worry about, it would make more sense to worry about an alien space ship crashing on your house and killing you than it does to worry about BECs forming destructive black holes. While it is ridiculously unlikely that such a crash will occur, at least it is conceivable within the laws of physics, while formation of a black hole from a BEC is absolutely and utterly far outside the realm of any possibility." By Former Nuclear Safety Officer, Cosmic Ray Researcher and CBEST Math Champion, Walter L. Wagner.
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And yes lightarrow, energy would be quantized if frequency were fixed, but its not, so it isn't. That's my whole point.
But probably it's a matter of definition. Which is the definition of the statement "Energy is Quantized"?
I think that *your* definition is that energy in general can only have integer values of a fundamental unit E. But does this definition match with the real one? No.
You can say that it's an improper way to say things, and maybe we could agree on this, but we can't question definitions.
What is quantized in the sense that you mean, is the "action" not the energy.
Geezer: your idea of integer numbers of cycles is correct but you have to apply it to the action, not to the energy. In the classical limit, the phase of a wavefunction is S/h where S is the classic action. So the fact that action is quantized is the obvious fact that the phase of a wave comes in integer vaues of 2π.
After I have "discovered" this trivial truth (not long ago) I started to realize that the concept of "phase" is very important, probably is the central concept in physics (the principle of minimum action becomes that of the minimal phase).
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Geezer: your idea of integer numbers of cycles is correct
Wow! It was an uneducated guess [;D]
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Geezer: your idea of integer numbers of cycles is correct but you have to apply it to the action, not to the energy. In the classical limit, the phase of a wavefunction is S/h where S is the classic action. So the fact that action is quantized is the obvious fact that the phase of a wave comes in integer vaues of 2π.
After I have "discovered" this trivial truth (not long ago) I started to realize that the concept of "phase" is very important, probably is the central concept in physics (the principle of minimum action becomes that of the minimal phase).
And this underlies much of modern quantum mechanics, since that's what Feynman diagrams and modern quantum field theory use. And they also underly the relationship between ray optics and wave optics (which was Feynman's inspiration for introducing his work on path integration in quantum mechanics). If you have waves taking many possible paths, the contributions which end up mattering are those very close to the minimal action (or maximal action).
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In chemistry we learned, E=hν which means energy equals planks constant times frequency. Our professor (and our book) then suggests that this means that energy can only exist in certain quantized amounts that are integers of planks constant. Is this true? The way I see it, assuming this equation is correct (which I am) this in no way suggests that electromagnetic energy is quantized. because ν, frequency, is not an integer. It can be any possible value, and any possible value times a constant can be anything. And if energy can be anything, that is the opposite of quantized. But that is not at all how it is being represented to us in class or in our literature. Am I missing something?
EM energy is quantized *fixing the frequency*. If frequency is free, then you can have whatever energy you want.
Not sure what that means.
To be precise, the EM field is quantized by quantizing the fiel into photons. I don't see where the frequency of these photons are fixed. What about a static electric field?
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In chemistry we learned, E=hν which means energy equals planks constant times frequency. Our professor (and our book) then suggests that this means that energy can only exist in certain quantized amounts that are integers of planks constant. Is this true? The way I see it, assuming this equation is correct (which I am) this in no way suggests that electromagnetic energy is quantized. because ν, frequency, is not an integer. It can be any possible value, and any possible value times a constant can be anything. And if energy can be anything, that is the opposite of quantized. But that is not at all how it is being represented to us in class or in our literature. Am I missing something?
EM energy is quantized *fixing the frequency*. If frequency is free, then you can have whatever energy you want.
Not sure what that means.
To be precise, the EM field is quantized by quantizing the fiel into photons. I don't see where the frequency of these photons are fixed. What about a static electric field?
If you fix the frequency of the field, say for example making it perfectly green light of a given frequency, then the absolute smallest packet of energy you can see is 1 photon of that green light. You can't subdivide the field into any smaller energy packets than that one photon. You're free, of course, to choose any frequency you want, so those tiniest packets can be of different sizes if you choose a different frequency, but in all cases, there is a smallest packet of energy for your field and it is 1 photon.
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:)
http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton.27s_second_law
Energy,,what is it?,, and what need to be exist,, that we can calculate energy?
F=ma,, m=mass,,m=matter
So,,we need matter, and therefore Energy is matter-motion result.
Without matter, mathematical calculated and technical system measured energy, cannot exist.
http://en.wikipedia.org/wiki/Planck_constant
I dont see that E=hv formula any m=matter,,so it cannot be nature thruth?
- Wave cannot made energy without matter-motion.
- Wave cannot exist without matter=m.
That is my thought,,can be wrong or right,,but that is my thought how i see this nature-situation with mathematical formulaes.
All physics theoretical stuff is not describe of nature-world,, i think,,:)
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JP
"You're free, of course, to choose any frequency you want,"
In my opinion your are not free to choose any frequency you want I believe that the wavelength can only changed in discreate multiples of the Planck unit of length 1.6*10-35 m.
This has no practical effect now but may have been a factor during the 'big bang'
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JP
"You're free, of course, to choose any frequency you want,"
In my opinion your are not free to choose any frequency you want I believe that the wavelength can only changed in discreate lengths of 1.6*10-35 m the Planck unit of length.
This has no practical effect now but may have been a factor during the 'big bang'
That's interesting. We should be able to detect those steps in frequency/wavelength. I always assumed the spectrum was continuous, but this would suggest it is not.
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Not sure what that means.
To be precise, the EM field is quantized by quantizing the fiel into photons. I don't see where the frequency of these photons are fixed. What about a static electric field?
I have not written that the frequency of these photons are fixed. As JP wrote, what I mean is that if you let the frequency f be as free as you want, you will never find a smallest packet of energy:
lim hf = 0.
f→0
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JP
"You're free, of course, to choose any frequency you want,"
In my opinion your are not free to choose any frequency you want I believe that the wavelength can only changed in discreate lengths of 1.6*10-35 m the Planck unit of length.
This has no practical effect now but may have been a factor during the 'big bang'
That's interesting. We should be able to detect those steps in frequency/wavelength. I always assumed the spectrum was continuous, but this would suggest it is not.
Do you have in mind the separation between the two lines of the sodium's doublet? (one line of the doublet is at 589.0 nm, the other at 589.6 nm) You have 4*1025 possible lines between them. Are them enough for you? [:)]
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The question posed is 'Is Electromagnetic Energy Quantized' I agree that Quantization is not very apparent at optical frequencies but in the high temperature era early in the big bang it may well of had a part to play
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The question posed is 'Is Electromagnetic Energy Quantized' I agree that Quantization is not very apparent at optical frequencies but in the high temperature era early in the big bang it may well of had a part to play
Interesting point, though I'm not sure if there's any way to test the idea that EM. My feeling on the Planck units is that they're just an issue with our current theories, i.e. the standard model would need to account for quantum gravity at sub-Planck scales, which it doesn't currently do. Therefore we can't reasonably make predictions in that region, but the Planck length might not have fundamental physical meaning other than us needing a better theory at those distances. If string theory turns out to be right, from what I understand it does explain some sub-Planck structure. Then again, the Planck length might be something extremely significant, but we just don't know yet.
By the way, if we're going to talk about Planck units, there is one thing that's bugged me with the explanation that they're special or in some way signify a breakdown of our laws of physics. The Planck mass is huge compared to the other units: roughly 20 micrograms. We can see things under a microscope with masses less than this...
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If you fix the frequency of the field, say for example making it perfectly green light of a given frequency, then the absolute smallest packet of energy you can see is 1 photon of that green light. You can't subdivide the field into any smaller energy packets than that one photon. You're free, of course, to choose any frequency you want, so those tiniest packets can be of different sizes if you choose a different frequency, but in all cases, there is a smallest packet of energy for your field and it is 1 photon.
That was not what I was referring to. I was addressing the more general question regarding quantum field heory and the photons that make up the field. Those photons are, of course, virtual.
Regarding quantinization - Quantum mechanics doesn't imply that energy is always equantized. E.g. consider of a free particle. The quantum state has a continuum of energy states. The energy is only quantized when certain conditions hold true, e.g. when a particle is moving in a potential well.
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Ah, I did misunderstand you. I do agree that the physical process determines what frequencies of photons you can get. Since these processes can vary, there is no rule saying that you can only get certain frequencies of photons in the universe.
However, quantization of light usually refers to the fact that each photon, no matter how it's been generated, cannot be sub-divided in energy. It also refers to the fact that classical monochromatic light is in what's called a coherent state, and in that state, it is made up of only one kind of photon, so that there is a minimal packet of energy for that kind of light.
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JP
"You're free, of course, to choose any frequency you want,"
In my opinion your are not free to choose any frequency you want I believe that the wavelength can only changed in discreate lengths of 1.6*10-35 m the Planck unit of length.
This has no practical effect now but may have been a factor during the 'big bang'
That's interesting. We should be able to detect those steps in frequency/wavelength. I always assumed the spectrum was continuous, but this would suggest it is not.
Do you have in mind the separation between the two lines of the sodium's doublet? (one line of the doublet is at 589.0 nm, the other at 589.6 nm) You have 4*1025 possible lines between them. Are them enough for you? [:)]
I suppose it would! Thanks!
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However, quantization of light usually refers to the fact that each photon, no matter how it's been generated, cannot be sub-divided in energy. etc.
Exactly! :)
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By the way, if we're going to talk about Planck units, there is one thing that's bugged me with the explanation that they're special or in some way signify a breakdown of our laws of physics. The Planck mass is huge compared to the other units: roughly 20 micrograms. We can see things under a microscope with masses less than this...
But you should confine those 20 micrograms in a 10-35 m radius black hole:
http://en.wikipedia.org/wiki/Planck_mass
The Planck mass is the mass of the Planck particle, a hypothetical minuscule black hole whose Schwarzschild radius equals the Planck length.
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There are several tings I wonder about there :) But let's take Planck mass fist.
"The Planck mass is the mass a point particle would need to have for its classical Schwarzschild radius (the size of its event horizon, if you like) to be the same size as its quantum-mechanical Compton wavelength (or the spread of its wave-function, if you like). That mass is 1019 GeV/c2, or about 10-8 kilograms." So the concept of a plank mass being important to physics seems to be that it is at the relative size where general relativity and quantum gravity effects both can act on it. And that way the Planck length gets defined by that point particles possible mass.
If you compress that particle any more (Schwarzschild radius) you will get a black hole as Lightarrow pointed out. And if you look at the Compton wavelength you will find that it is what seems to define the border for where Quantum mechanical effects take over. Combining those two formulas "and solve for m, we find that at a mass of (hc/G)1/2 (about 10-5 g) the Schwarzschild radius and the Compton length are equal. This mass is called the Plank mass. The length at which the Schwarzschild radius and the Compton length are equal is called the Plank length. At the Plank length, both relativistic and quantum affects are equally dominant."
The Schwarzschild radius is given by Gm/c2 and the Compton length by h/mc. Then one also have to remember that 'point particles' is assumed to have no spatial size what so ever. Like a electron, and that seems to be proved by scattering experiments where they act different from what you can expect of particles of a definite size. And as we know, they can also become superimposed, in this case being in two locations at the same time, which is another excellent reason for calling their orbitals orbitals, instead of orbits which we use macroscopically.
But then we come to light. In the particle definition of photons we find that it is its frequency (the amount of waves passing a given point in time) that will define the energy. But if we instead look at waves the definition seems to be its amplitude (think of that as the highest and lowest points of a wave. Or as a 'length/measure' made of its vibrations up and down.)
So a waves amplitude is a photons frequency? If we now think of a wave getting 'expanded/red shifted' in space by a 'expansion'. How do I describe that as photons? As fewer passing some certain point in time? But a photon can also be sent one and one, as we define it? Or should I consider it as its 'frequency' changing by the expansion'? How can there be a frequency in one photon, quantized 'energy' is easier to accept for me that any frequency. To me it seems that all this started with assuming waves studying 'black body radiation'?
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And what about a relative blue-shift as observed between two spacecrafts meeting? If looked at as waves it will then be the amplitude, but not the frequency changing? Well, not entirely true as you will see both a Lorentz contraction and Doppler Effect, but I should still have to define the energy increasing as having deeper troughs and higher crests?
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If I got this correctly a single photon can't be 'red shifted'. The only thing that can red shift here is its position relative its companions (other photons) But that becomes weird to me. Easier to see it as a 'continuous' wave although that too becomes weird as we then will define energy as the (length too?) heights and troughs passing in that 'expansion'. But why would that decrease the height of it? Why couldn't it as easily be seen as just 'lengthening it' but staying on that 'height' when looked at purely as geometry? To assume that it 'sinks' is the same as having two poles with the wave as a slack rope in the middle, hanging in a bow. Then the 'expansion' would be the poles moving in opposite directions tensing that rope and stretching it, making the bow shrink into a line at some point, as it seems to me?
The other way is to assume it as something magnifying all positions. In that case any point of your wave will be added too, in three dimensions simultaneously, but there will be no bow 'shrinking' instead the wave will only get 'enlarged' in each point, begetting more points.
Well?
As I (naively) think of it.
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I agree with what most of you guys are saying now, we are coming together a bit. However, I do think that most people think quantized energy levels for photons means something completely different than basically, "light is carried by photons".
Anyways, Yor on, I think you bring up a very good point, and I never thought about that before. I have an answer for you, but its based upon my own (completely anti-particle) stuff, not modern physics.
However figuring out all the little nuances for how a "group" of things creates quantized objects, with "sometimes" quantized forces takes a ridiculous amount of work. It's not simple, to change directions from an all particle theory, like we are basically using now, to a completely divisible one like I am using, requires an enormous amount of new logic. You can't say anything without it appearing to have a million problems. I'll post my basic conceptual picture of what I think "particles" are.