Resolution Of The Heisenberg Uncertainty Principle 50
What does this mean? Femtosecond resolution apparently provides the localization needed to treat electrons as classical spheres in space, nearly following Newtonian physics. However, femtosecond chemistry has been around for years, so why hasn't this worked yet? Well, there is a great deal of error in gathering energy values, even when energies are collected at femtosecond intervals. This is due to freaky quantum physics i don't understand. But, as Zewail states, 'this freaky quantum error can be nearly eliminated if the matter is made coherent'. This means that the wavelike properties of matter are superimposed leading to the addition or destruction of waveforms. This is like the 'double slit experiment', in which regular light is shown through two slits, the waveforms either completely add or subtract, and what you see on the wall is a bunch of tiny spots of light at a defined point in space."
Re:f=ma? (Score:1)
Re:measurement problems (Score:1)
Clarification of Zewail's result (Score:2)
The second point is that is Zewail had actually found a violation, or even a slight deviation from HUR, he would win massive instant fame. He has done no such thing, and does not even claim to.
He never mentions "F=M*A", and those concepts do not appear anywhere in the paper.
What he has really done is a kind of quantum mechanical analog to the Mossbauer Effect. The key in both cases is to realize that the coherent behavior of a large group is quite different from that of single atoms, and creates a whole different situation for measurement. This is yet another vindication of QM, and another reminder that QM is quite counter-intuitive, even for those who make a living at it.
Quantum Computers and Decoherence (Score:1)
Now, if this is true, then I guess quantum computation must have higher hopes then. The biggest problem with building a practical quantum computer is that in most physical quantum systems decoherence phenomena will randomize the state of your qubits before you can make any kind of useful calculation. Present research in quantum computing has focused on attempting to find physical systems where you can compute and read out the result of your computation before decoherence sets in. If a coherent quantum superposition is really more stable than initially thought (and as Zewail suggests), then a practical quantum computer might not be as hard as everyone thinks.
Re:God does not play dice. (Score:1)
Its a theory. So it can't be proven. And most theories in physics are math - this isn't biology. If you could point us to a theory that explains the same phenomena as relativity (and does it as well), then I'd be more than willing to take it into consideration. But don't go around calling him a dumb Jew and using that as a reason to call his theory false.
Relativity supporters are not completely closed minded to something better coming around sometime in the future. But right now, it's the best thing we've got.
Re:Astounding (Score:1)
Astounding (Score:4)
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Re:f=ma? Last post I promise (Score:1)
Re:God does not play dice. (Score:1)
If you want your measurements to confirm relativity, then they must all confirm my theory too.
Re:some clarifications (Score:2)
Guess you didn't try this experiment in physics class. Anyone who wan'ts to see for themself, I recommend an ordinary Tungsten filament light bulb, a card board box, and two slits from a razor blade in a dark room.
Don't feel bad. An alarming number of my students in a junior level physics lab at MIT were suprised by this.
measurement problems (Score:2)
Simple explanation: How do you measure the energy value (tantamount to speed or momentum) of an electron? By looking at it. How do you look at it? With photons. What happens when a photon hits an electron? They trade some energy. What is it you were trying to measure? . . .
If you bombard a subatomic particle with other particles, and do it 10^12 times per second, of course you're going to have a hard time keeping the answer straight, because your measuring device is causing the answer to change.
Suspicious (Score:2)
Ahmed Zewail is quite the physical chemist, and I have a lot of respect for him and his work. However, I have to be suspicious of such a claim, which might just be journalistic hype for what little I know.
I have to wonder if there's a shell game, where "incoherence" is a synonym for rejecting those particles whose (x,p) values would pollute the probability distribution in favor of Heisenberg's inequality.
Re:Clarification of Zewail's result (Score:2)
More than when he won the Nobel Prize in Chemistry in 1999?
Re: Resolution Of TheHeisenberg Uncertainty Princi (Score:4)
This is all great news, but... (Score:1)
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Re:some clarifications (Score:1)
Re:f=ma? (Score:1)
And maybe you've never heard of 'wave-particle duality' either. Go figure. That's pretty fundamental to quantum mechanics. Photons can act like waves or particles, depending on the situation. Light is NOT measured in waves, it's measured in quanta. That's another little nugget of fundamental quantum mechanics you neglected. Light has a wavelength, but that's not a quantitative measurement. Knowing the wavelength of some light will not tell you how much of it there is.
And the mass of a photon is not 'very tiny'. Photons are virtual particles. They have no mass, by definition. As far as different 'color' photons being of different 'masses', that's relativistic mass. Relativistic mass depends on velocity. Real mass doesn't. M = E_0 / c^2. E_0 is the energy of the object at rest.
Energy does not really exist? What is that supposed to mean? Do you know the difference between 'does not exist' and 'is not matter' ? Anything that affects reality in any way 'exists'. Of course energy is not matter. You could just as easily (and more correctly) say that velocity and mass do not exist, being spinoffs of energy. And I really have no idea what your last three sentences are supposed to mean, but I suspect you aren't familiar with the Constancy of the Speed of Light principle. If that's not what you're getting at, I certainly hope English is not your first language.
I strongly suggest you actually pick up a book and read something about relativity and quantum mechanics, because your seem to know about as much about the two as any American who has never read anything more in-depth than a high school physics text book. I personally recommend Hawking's A Brief History of Time.
Re:f=ma? (Score:1)
I also find it curious that you are mixing material particles and virtual particles in your arguments, as if they have anything in common. I believe you don't understand the fundamental difference between a mass-carrying particle and a virtual particle, and the fact that one cannot be expressed in terms of the other. You are trying to explain photons, which are virtual, in terms of electrons, which are material. Don't do that.
Re:f=ma? (Score:1)
And someone like you saying 'get a clue' is exactly the ad hominem crap I'd expect from someone who is willing to believe a priori that a theory is false, simply because they want to believe that. You certainly are a metaphysicist, and not a philosopher. You're only engaging in escapism to continue your line of thinking, and I've done my best to try to explain why the people that came before you that thought the same things abandoned their unreasonable theories. You have no grasp on many fundamental laws, and I will only cite one more. Ockham's Razor. You are certainly inventing unnecessary steps.
No matter how ad hominem your reply to my other post is, let me lay your mind to rest here: I'm not going to reply to it.
Re:f=ma? You are such a troll. (Score:1)
Uncertainty Haiku (Score:2)
I observed the article
Now i'm not so sure.
Re:God does not play dice. (Score:3)
Re:f=ma? Last post I promise (Score:1)
because photons do have mass, just not rest mass. they have 'relativistic' mass. they have momentum. they have no rest mass because they are never at rest, duh.
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Re:f=ma? (Score:1)
1) The Pauli Principle: Electrons at lower energy states prevent the other electrons from going there. The reason why something like "states" exists is the wave-like nature of particles (electrons), which give also rise to:
2) The Heisenberg Uncertainty Principle: If the electron would be at rest (in the nucleus, or anywhere) it would have infinite uncertainty in momentum, i.e. in the next instant it would be somewhere else (and you wouldn't know where). So it IS possible for electrons to be at the position of the nucleus, but only for a very short time (this leads to something called "Fermi-Contact-Interaction" between s-electrons and nuclei).
Re:some clarifications (Score:2)
I think our problem is that "regular light" was not defined exactly enough.
some clarifications (Score:3)
a) it's a matter of numbers
b) coherence (which is needed for spatial localization) is not as instable as initially thought
for a) it's important to remember that he is talking about positions of NUCLEI which are quite
heavy objects (compared to e.g. electrons). Heavy objects have large momentum (p=mv) therefore a small uncertainty is not as disturbing as for light objects.
Now some comments on Hemos' text/questions:
Femtosecond resolution apparently provides the localization needed to treat electrons as classical spheres in space, nearly following Newtonian physics.
No, he is talking about "atomic motion", i.e. about nuclei. See above.
However, femtosecond chemistry has been around for years, so why hasn't this worked yet?
It has worked. The article is just a summary/explanation of why it has worked.
Well, there is a great deal of error in gathering energy values, even when energies are collected at femtosecond intervals. This is due to freaky quantum physics i don't understand.
The error is given by the HUR: Delta(E) >= hbar/(2*Delta(t)). The shorter you look, the larger the uncertainty. However, it turned out that the timescale of several ten femtoseconds is still large enough to have sufficient energy resolution.
This is like the 'double slit experiment', in which regular light is shown through two slits, the waveforms either completely add or subtract, and what you see on the wall is a bunch of tiny spots of light at a defined point in space.
No. The double slit experiment doesn't work with regular light, you need *coherent* light (e.g. a Laser). That's exactly the point Zewail makes: if they had used incoherent states (or if the coherency was destroyed fast) they would not have observed localized atoms ( = your "tiny spots of light")
Future Uses... (Score:1)
IBM had PL/1, with syntax worse than JOSS,
Hum (Score:1)
Re:f=ma? (Score:1)
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Re:f=ma? (Score:1)
On effecting the velocity of an electron. Momentum=MV. The mass of a photon is very tiny. It would take a very high velocity to change the course of one electron or millions upon millions of photons. I agree with you on this point. Anyways, the point is, Energy does not really exist. It is a measurement of velocity and mass. People always seem to forget about relativity when talking about velocities. All masses have relativity, even very small ones and that changes what the value is measured as. We are just so used to having approximately the same relativity because Earth and the stars are traveling relatively compared to the velocity of a light particle.
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Re:f=ma? (Score:1)
I am not so happy with your claim that energy does not exist... one could argue that mass does not exist, it is merely energy condensed to a slow vibration. I could easily argue that too. I don't believe it but I could argue that mass does not exist. Their is also an interesting theory that mass does not exist(and I did a 20 page philosophy report on this(believe it or not)) on the basis that if you look at something like a proton and you zoom in really close, what do you find, a particle divided among many particles. If you look at one of these particles and zoom in farther, what should you theoretically find, a particle that is actually composed of even smaller particles. If you zoom in one of those particles, what should you find, a division among smaller particle. Repeat the cycle. So, in theory, their is almost no mass in a particle. Their are naturally problems with this theory and is based on a hierarchial system of zooming in on something like a galaxy. Anyways, everything we are argueing about are still in theory and none of them have been proven to the satisfaction of the world or becoming a law.
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Re:f=ma? (Score:1)
As for my philosophy report, I got a pure A. It was an Arguement against St. Thomas of Aquinas fifth arguement in his five ways of St. Aquinas(the argument against Intelligent Design). It's completely theory with a lot of Umph behind. I'm not the person who came up with the theory or am I the one who keeps the theory going. Their are a lot of facts behind it. None, 100% conclusive but still, they exist. Everything we are talking about is still theory and most of it hasn't been proven. Until I see proof otherwise or actually have evidence for your case, I will be inclined to go against it.
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Re:f=ma? (Score:1)
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Re:f=ma? You are such a troll. (Score:1)
I know what the hell 'Priori [maths.org]' means, I'm just ignoring it. It relates more to you then me. Mostly everybody believed the world was flat once but is that the case. NO(I said that about 2 posts ago.) I agree with the Anonymous Poster, you need to have a more of an open mind. Something with as little proof as their is needs to be questioned. I spilled theory on your plate. I never said it was right. I said it had the possibility of being right. I don't agree with Einstein's theory of relativity because it has problems(too many assumed unproven theories.) I've read many Physics books and have taken several physic's classes and understand theory. I just don't agree with it. I'm probably in a better position to argue because I ACTUALLY UNDERSTAND PHYSICS. Their are more then one theory, live with it. Try to prove yours right. I'll believe it when I see it. Like I said earlier, everything we deal with are still theories. Just because millions of people believe something and continues the theory by researching it and building on it, does not make it more right. People will believe what they want to believe.
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Re:f=ma? (Score:1)
Energy is something that can be measured but isn't real as it actually exists. It is the product of several components. Einstein crossed the line and said Energy existed and could be converted to Mass and Mass could be converted to energy as what happened in the big bang. I don't see it. Energy has never been proven to exist without the existence of Mass. So far, you need mass to have energy and energy to have mass. If you set the m=0 in the formula Energy = Mass * Velocity^2, Energy suddenly equals 0. Suddenly, we have a problem. Anyways, my point is: either mass exists or energy exists, not both or it leaves the remote possibility of this formula being wrong. Science has yet to solve this problem conclusively.
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Re:f=ma? Last post I promise (Score:1)
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Re:f=ma? (Score:1)
Just because someone has a difference of an opinion than you does not make them stupid or a troll. I'm actually quite an intelligent person(I don't use the preview button before I press submit and check my mistakes) but I'm still an intelligent person with an opinion and you sir are a Lemming.
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Re:f=ma? Last post I promise (Score:1)
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Re:f=ma? Last post I promise (Score:1)
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Re:f=ma? (Score:1)
On the other, you are _not smart_. On the other hand, I am smart and you are dumb. Dumb I say. Anybody else enjoying this more then I am. I get sick of dumb people who call other people dumb because they have nothing better to do and instead of trying to refute someone elses claim, they resort to name calling.
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Re:f=ma? (Score:1)
You can find many people who will refute any given theory, and seemingly quite intelligently. The trick is finding one of these people who isn't a raving paranoid looney. There are plenty of people out there with websites who can give you reams of evidence that everything you know is wrong, but then discredit themselves by claiming the government killed their dog to shut them up, or claiming that satan lives in their microwave. Their are also people who are willing to jump off a tall building because a comet passed near the Earth, doesn't mean the majority is right, it just means it is more accepted.
I didn't know that. I guess all this quantum mechanics stuff is bullshit. I never ditched Quantum Physics. I actually agree with 99% of it. I'm sure most of it is true. Since we can't really see electrons, we can pretty much guarantee that not all of it is going to be true but most likely, most of it will be true.
As for f=ma, it was the first thing that popped into my mind. I could've came up with a better formula like d=do +vt+1/2A*t^2+1^/6dA^3 +1/24dda^4+1/120ddda^5 +
As for the cursing and shit like that, I just do it because I'm bored and having nothing better to do. If I wanted to be professional, I would. Fortunately, this is a publc forum and I can say whatever I want.
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Re:f=ma? (Score:1)
Anyways, this forum has been the longest one I've ever replied to. Do you really want to know the truth about me? Here it goes. I like to piss people off. I like saying things to get responses. I like to argue. I don't care if I'm right or not or if the other person is right or not(I'm still going to dispute Einstein's theory of relativity because it really assumes too much how things are(as I said in an earlier post, the math might be right that explains a phenomenon within a specified range but the reasoning behind it still might be wrong)) I just like to argue. I'm sorry for calling you stupid, I don't know if your stupid or not. If you can even understand Einstein's theory of relativity, you must have atleast an IQ of 120 which is better then most people. Anyways, argueing is fun, don't you agree? I love to argue. I'll go down a path that I know is completely wrong if I can argue it and if asked a question against myself, I would argue it too. I just enjoy it that much. I'm really quite intelligent when it comes down to it. I haven't got where I've gotten in life by being stupid(in other words, I didn't join the Army.)
The main points I have against the theory of relativity include:
1) Is their anything really special about the velocity of light.
2) Why would relativity at the speed of light change when the relativity below the speed of light is normal.
3) The space-time continuum problem. Does time exist. In other words, can we make time non-linear. I have yet to see proof of this.
4) The energy->mass->energy conversion problem.
It's been fun but I have to go.
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Re:enter pot, stage left... (Score:1)
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Re:God does not play dice. (Score:1)
Re:God does not play dice. (Score:1)
Re:f=ma? (Score:1)
I'm going to be all nit-picky and say that electrons are pretty darn small, essentially point particles, while photons are just energy so they have no size, so the size argument doesn't make any sense. Furthermore photons really only travel at one speed, c (the speed of light, go figure), so they are often going much faster than electrons unless you've got highly relativistic electrons. However, their frequency (not their speed) defines their momentum, as a blue photon has more momentum than a red photon: p=h/lambda (where lambda is wavelength).
Pretty sure though that your average blue photon (lambda = 400nm) has p=10^-28 kgm/s about, while an electron will have between p=0hell... I could be wrong... I haven't been in school for a while.
-your sig, it taunted me!
Re:f=ma? (Score:1)
A single photon can still have a "frequency" and thus a single quanta of energy, momentum or "mass," if you will, one can definitely produce single photons of different energy, or momentum (for you who does not believe in energy), in the same medium; its done everyday and it is even measurable. Frequency can be merely a way of expressing the amount of energy or momentum a single photon has.
I am not so happy with your claim that energy does not exist... one could argue that mass does not exist, it is merely energy condensed to a slow vibration. Anyway... these are fairly fundamental things and the only point of my post was really to say that I do remember relativity, albeit imperfectly.
Comment+Clarification (Score:3)
First, Zewail apparently has been pushing these ideas for some time, and Nature just gave him the opportunity to get it publicized a little. This is theory, people aren't going to go simultaneously calculate position and velocity of fundamental particles this afternoon, but he theorizes that with these two conditions met, such a characterization could be possible. As far as I understand, that is all he is claiming.
Second, when I said "he proposes in a recent issue of Nature...that one can solve, USING CLASSICAL PHYSICS (ie: f=ma)..." the (f=ma) is an EXAMPLE of what classical Newtonian physics is. I am not sure how that got misunderstood, but I apologize for my ambiguity. Perhaps it would have been better to simply quote Zewail as I will do now: "But if these waves are added up coherently with well-defined phases, the probability distribution becomes localized in space. The resultant wave packet and its associated de Broglie wavelength has the essential character of a classical particle: a trajectory in space and time with a well-defined (group) velocity and position - a moving classical marble but at atomic scale!" (Nature 2001, 412, p.279).
Even if my explanation was convoluted, I simply hope to get across Zewail's main idea: that quantum uncertainty is no longer an obstacle, and therefore openening the theoretical possibility for the resolution of HUP.
Raising an eyebrow (Score:2)
Re:f=ma? Last post I promise (Score:1)
The quick and dirty proof of photons having no mass is from E=mc^/sqrt(1-v^2/c^2) which is the correct Einstein equation. (It is so frustrating that people insist on using E=mc^2, which is only a special case) You can see that in a vacuum v=c, therefore E=infinity unless m=0. Obviously infinite energy is impossible so m=0. If m=0, then E=0/0 and 0/0 is an indeterminate number which is allowed, but doesn't give a solution. You can't use this equation to find the energy of the photon. For that you have to use the QM equation E=hf. For a good FAQ on the topic see http://math.ucr.edu/home/baez/physics/photon_mass