Why Quantum Physics is Cool Pt 2 (Updated with pt 3 URL)
Created on: September 23rd, 2006
Continuation of http://quantamiscool1.ytmnd.com
Part 3 at http://yqpic3.ytmnd.com/
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These conclusions have been drawn from over 50 years of experiments. And it still stands that when they don't observe an exact path or velocity of a particle, it always yields interference patterns.
Mathematically the results prove that the particle must be at more than one place at the same time. Which would be kind of a paradox. But the particle always goes back to normal when we try to observe the paradox.
Hah! I know this one! It's all to do with the Heisenberg uncertainty principle, which, in it's most basic form, means, that it is impossible to simultaneously measure the speed or position of a particle with certainty! Wiki Heisenberg Uncertaintity Principle for some light Quantum Physics reading. Man, i wish my physics teacher was cool...
^ "These conclusions have been drawn from over 50 years of experiments" ... WRONG! This is a subject that interests me, and I've read a lot on the subject and talked to a lot of people... Hot Pockets have only been around for about 25 years. Experiments on them took place slightly before that, in the 70's, but not 50 years ago! That's crazy! 5 for crazy
It is misleading to say that by merely opening and closing your eyes, you could afftect the wave pattern. A more realistic example would be that you would need a flashlight to see the electrons, and when you turned it on, the photons from your flashlight interacting with the electron probability wave force it to collapse.
The problem with the whole "it behaves this way when we watch and this way when we don't watch" is that the method of observation, under our current understanding of causality and statistics, necessarily is correlated with the results. The results are not repeatable (a necessary condition of empiricism) and thus no results can be derived from one to the other. The other stuff, having to do with "willpower" which, eventually, will be defined in more technical terms of physical behavior in the brain I would imagine, is interesting. It also makes sense that the electromagnetics in our body would be able to affect the outside world, especially one particle at a time...
The act of watching the photon doesn't change the experiment the act of measuring the photon changes the experiment, please don't start with this whole O YOU CHANGE THE RESULT bullsh*t, http://en.wikipedia.org/wiki/Measurement_problem to find the truth behind the problem, the problem lies with measurement not with observation
To keep from getting technical since we don't have room for an entire thesis, basically how can the measurement cause the collapse? I mean, there has to be a collapse since when there is no measurement of which slit or mirror, the ending result can only be explained by the particle traveling through both slits/mirrors, otherwise you wouldn't get the interference pattern. Further shown to be the case when you DO measure which path, it only goes one path and makes no interference pattern. If electrons constantly act as waves, how can measuring their trajectory make them suddenly act like matter?
Because they ARE particles of matter, and they will act the way we THINK they are going to act - lest one of the other 7 theorized dimensions composing and upholding our existence rip open and spill the all-consuming truth into our own - and we'll be REAL f*cked then, won't we? F*cked like the wavefunction of a housecat's particle. I bet that'd satisfy you RIGHTLY, to see our Universe fold in on itself because we finally witnessed the inner-workings of a mathematical paradox. I bet you'd get off on that.
The only problem with this is: How can you define 'observation?' Is a fly enough to change it? A dog? A cat? Are only -humans- enough to actually change what's going on? If the last is so, you step into the world of . . well, is arrogance the right word? Kind of takes me back to the whole "only humans have souls" thing, which is strictly religious in nature, not scientific.
Once again you stole that presentation from "What the Bleep do we
Know?"
I'll give you $20 if you can find the laser splitting experiment on What the Bleep. I saw that movie like 3 years ago, and they have no copyright on scientific fact. That movie was a nutjob new age hippie fest that needs to never be called science.
large heaping amounts of fail
light is not carried by electrons . light is EMITTED by electrons with frequency equal to the frequency vibration of the electron.. So wouldnt that infer that obviously at each point that the light that is emitted behaves, obviously, as a wave. Saying that light is carried somehow through or by matter is ridiculous.
its amazing how few people have taken an actual class in physics
however......... 5'd for hotpockets!
So far, we have shown how one goes from an ordinary quantum theory to a quantum field theory. There are certain systems for which no ordinary quantum theory exists. These are the "classical" fields, such as the electromagnetic field. There is no such thing as a wavefunction for a single photon in classical electromagnetisim, so a quantum field theory must be formulated right from the start.
The essential difference between an ordinary system of particles and the electromagnetic field is the number of dynamical degrees of freedom. For a system of N particles, there are 3N coordinate variables corresponding to the position of each particle, and 3N conjugate momentum variables. One formulates a classical Hamiltonian using these variables, and obtains a quantum theory by turning the coordinate and position variables into quantum operators, and postulating commutation relations between them
For an electromagnetic field, the analogue of the coordinate variables are the values of the electrical potential and the vector potential at every point . This is an uncountable set of variables, because is continuous. This prevents us from postulating the same commutation relation as before. The way out is to replace the Kronecker delta with a Dirac delta function. This ends up giving us a commutation relation exactly like the one for field operators! We therefore end up treating "fields" and "particles" in the same way, using the apparatus of quantum field theory. Only by accident electrons were not regarded as de Broglie waves and photons governed by geometrical optics were not the dominant theory when QFT was developed.
Supersymmetry assumes that every fundamental fermion has a superpartner which is a boson and vice versa. It was introduced in order to solve the so-called Hierarchy Problem, that is, to explain why particles not protected by any symmetry (like the Higgs boson) do not receive radiative corrections to its mass driving it to the larger scales (GUT, Planck...). It was soon realized that supersymmetry has other interesting properties: its gauged version is an extension of general relativity (Supergravity), and it is a key ingredient for the consistency of string theory.
The way supersymmetry protects the hierarchies is the following: since for every particle there is a superpartner with the same mass, any loop in a radiative correction is cancelled by the loop corresponding to its superpartner, rendering the theory UV finite.
A cat is placed in a sealed box. Attached to the box is an apparatus containing a radioactive atomic nucleus and a canister of poison gas. This apparatus is separated from the cat in such a way that the cat can in no way interfere with it. The experiment is set up so that there is exactly a 50% chance of the nucleus decaying in one hour. If the nucleus decays, it will emit a particle that triggers the apparatus, which opens the canister and kills the cat. If the nucleus does not decay, then the cat remains alive. According to quantum mechanics, the unobserved nucleus is described as a superposition (meaning it exists partly as each simultaneously) of "decayed nucleus" and "undecayed nucleus". However, when the box is opened the experimenter sees only a "decayed nucleus/dead cat" or an "undecayed nucleus/living cat."
The question is: when does the system stop existing as a mixture of states and become one or the other (see basis function)? The purpose of the experiment is to illustrate a paradox; as Schrödinger wrote:
"The [wavefunction] for the entire system would [have] the living and the dead cat (pardon the expression) [sic] mixed or smeared out in equal parts."[1] Because we cannot get along without making classical approximations, quantum mechanics is incomplete without some rules to relate the classical and quantum descriptions. One way of looking at this connection is to say that the wavefunction collapses and the cat becomes dead or remains alive instead of a mixture of both. NEDM!
"Also, if we were shrunk down, how would watching it with our own eyes
change from if we were regular size."
You would actually be able to see the evidence yourself. So i guess you could say it doesn't seem to be the physical action of watching, but rather the conscious act of seeing and knowing. Of course many argue that the measurement taints the evidence, but sight is also our form of measurement. So it's impossible to take all measurement out and have a truly unbiased truth. However, if the electron is going through both slits, in order to make the wave pattern (which it must since it doesn't with one slit) how does measuring it passing through one slit prevent its probability wave from traveling through the other???? Things to ponder.
You can't exactly bounce photons off an electron to "see" it. I'm not sure, but I think the scientists are using some type of magnet the electron has to pass by, or "shield" that the electrons has to pass through. Otherwise, how would you detect it? Either one of these (even bumping a photon off it) disturbs the path of the electron. I don't know exactly why this would cause it to act like a particle instead, but it is not simply just "watching" an electron that makes it do this. It's interference.
(link to some source material to where you found this information)
MMM ok
http://www.amazon.com/Fabric-Cosmos-Texture-Reality-Vintage/dp/0375727205/sr=8-1/qid=1159066966/ref=pd_bbs_1/002-6652836-9807224?ie=UTF8&s=books
http://www.amazon.com/Short-History-Nearly-Everything/dp/076790818X/sr=1-1/qid=1159066997/ref=pd_bbs_1/002-6652836-9807224?ie=UTF8&s=books
There's a start. I didn't get any of this off the internets :(
If you shrunk down to electron size, you still wouldn't be able to see the electrons unless you bounced photons off of them. (Or took energy out of their EM fields, or some other action which modifies the electron's properties). This action is much more likely to be what collapses the wave function, not the conscious act of seeing.
Ugh, um, you kind of fail at logic. Photons arent concious. When you fire them at a detector, the detector has to absorb them to detect them. So when you fire the individual photon off it gets destroyed. Or more likely, some of the energy is absorbed and that turns it into a particle.... Something like that.... Either way, I dont know why people do not see that.
"The act of watching the photon doesn't change the experiment the act of
measuring the photon changes the experiment, please don't start with this
whole O YOU CHANGE THE RESULT bullsh*t,
http://en.wikipedia.org/wiki/Measurement_problem to find the truth behind
the problem, the problem lies with measurement not with observation"
Note to self, read comments BEFORE posting your own...
The reason they act like particles when you're trying to observe them is because you have to pelt them with subatomic particles to locate them (photons?). It ruins it's individual probability wave when it interacts with another particle fixing it's path. The reason you can use photons outside of a vaccum in this experiment is because they're so small that the chances of them interacting with atoms in the air are slim. All matter behaves like a wave it's just waves cancel themselves out like you said.
You still didn't answer my question about DeBroglie wavelengths. Plus it is impossible to observe electrons with the eye. In order for such a thing to occur, the eye would have to shrink to the atomic level; in order for that to occur, the atoms and their subatomic particles would have to shrink. Using the eye to observe electrons is impossible; using a detector is different. Plus, it seems like kind of an old scientific postulate that, at the atomic level, something changes when observed.
The detectors themselves are made of different material (different molecules, atoms) than the mirror, and it doesn't seem so extraordinary that some kind of change would occur due to electron projection interference. Electrons don't "know" they're being watched, they simply respond to the attractions and repulsions of other subatomic particles.
Since these detectors are not "visual" (as far as I can tell, they require electron contact or response for measurment), it is highly probable that the subatomic particles within the detectors cause interference. If we could actually "visually" observe, which is impossible at this point (and will probably remain impossible), then I imagine the result would be much different.
Actually, think of it this way. If you are at a baseball game, you can watch a baseball cross home plate without changing it. But what if you're blind? What if you have no way of "visually" observing a baseball? The only way to understand it's movement is to touch it somehow, but by doing so, you would change the path of the baseball. Subatomic particles never "touch" they interact through electromagnetic energies, but the point still holds that "visual" observing would have a different result that
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