Heisenberg Principle, the uncertainty is because when we try to measure particles we interfere with them?
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I used to think that it was because we interfere with them, which was an early interpretation of the Heisenberg Uncertainty Principle, even offered by Heisenberg himself (see reference). However, my understanding is it closer to the statements such as \n\n1. Uncertainty is inherent in measurements\n2. Uncertainty is connected in some complicated way to differential geometry, and symmetries of the physical world (commuting variables exhibit a heisenberg-type inequality).\n3. We can quantify how the uncertainty in pairs of variables relate in a simple formula, similar to the uncertainty that exists between a variable and its Fourier transform dual variable (time and frequency, say). \n4. Uncertainty is a property of the universe. \n\nThe common statement about how trying to measure variables affects the results of the measurement (the so called "role of the observer" problem) is probably more closely associated with various gedanken experiments like Schrodinger's Cat, the EPR paradox and the double Slit Experiment.
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Hi, \n\nThat's too much like real work, but think about it like breaking pool balls in classical, and wave interference with quantum. \n\nHope that helps, \nMatt
730142
Possibly so. Possibly no. I'd say the Heisenberg uncertainty principle comes foremost into play here. Maybe also Schrödinger's cat. Is it dead or still alive? That would make a significant difference, you know. These questions can't just be taken so lightly. And how could you even consider Y!A as a forum to resolve such complex issues as this? More to the point, even assuming Planck scale dynamics can be fully understood with the mathematical tools we have at hand today, where exactly does that get us? We still don't know what topping to put on our pizza this weekend. Or whether a third eye would make a good chick magnet. Or even whether that darn cat is still alive or dead.... 'tis an enduring mystery. And we wouldn't want to take all the mysterious challenge out of life, now would we?....Meow.
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Newton's optics was based on light particles (photons). He could not have know about interference since no source of coherent light existed at the time for him to experiment with.
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No, there would be no interference pattern if light were behaving strictly as a particle.  If light acted only as a particle, the pattern seen behind two slits would be the superposition of the patterns seen behind two single slits.  That is, if light acted only as a particle, then you should see the same pattern whether you let light pass through two slits for five minutes, or whether you opened only one slit for five minutes, then closed that slit and opened the other for five minutes.\n\nOpening one slit at a time produces no interference pattern, leaving both slits open produces an interference pattern.  This cannot be explained by assuming a strictly particle interpretation of light.\n\n==============\n\nComment on "Additional Details #1"\n\nParticles of light have never been observed to bounce from one another.  Quantum electrodynamics predicts that they should, but the effect is so slight, and the probability so low, that there has never to my knowledge been a successful measurement of photon-photon scattering in the laboratory.  If the interference patterns in a Young's two-slit apparatus were to be explained by particles of light bouncing off one another, it would imply that light scatters from light very, very easily.  Crossing two flashlight beams would produce a diffuse glow from the area of intersection, and the beams would not continue onward to the places they were pointed.  We don't see that happening.  Another example:  if somebody is driving toward you with their headlights on, you cannot reduce the amount of light hitting your eyes by shining your headlights at them and deflecting their beam.
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People sort of understand waves and they understand particles, light might be a disturbance in the space time continum. Just a definate bit energy with an uncertainty where it is, traveling. Some "particles" exist for such a short time , they are more a resonance. I am looking forward to new research and thoughts on nature of light.
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There is a continuum between quantum laws and classical physics, they just haven't discovered a unified theory that expresses this continuum mathematically. Quantum laws govern all particles, and since matter is comprised of particles - naturally quantum mechanics supports material reality.\n\nuh... to "goring" - quantum mechanics does not posit that light has no mass.\n\nEinstein did not challenge all particle theory - when he said "god does not play dice with the universe" he was challenging Heisenberg's Uncertainty Principle, and quantum laws based on probability, which were subsequently validated in double-slit light experiments. So Einstein was wrong. He considered it his greatest failing as a scientist not to unify relativity with quantum laws in his lifetime.
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science people say so...\nbecause with measurements, everything is quantized.... and if something can't be quantized, like ghosts, then they are not real, or of no interest...\nbecause science people are interested with matters of consequence...
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at the atomic level, there is indeed randomness. you can predict the probabillity that things will occur, but cannot know for sure unless you make a measurement, which messes up the experiment because you "contaminated" the experiment with whatever you used to measure it. for instance, if you shine a flashlight at a double slit, half the light will go through 1 slit and half will go through another. however, if you turn down the output of the flashlight to 1 photon at a time, then the same thing happens. you cannot predict which one it will go through, it is completely random.\n\noh, and quantum theorry has been proven correct, better than any other theory out there - like newtonian physics, which have been shown to be approximations of the more accurate quantum theory.
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Science : May be uncertainty principle in quantum effect. \nMaths : Probability theory
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Probably not.  There are several problems\n\n1) because of the Heizenberg(sp?) uncertainty principle to learn of the exact direction of an atom one would change it's original direction.\n\n2) even if we could know a priori all that information it would require a simulation machine the size of the universe to calculate everything exactly.\n\n3)  I think there are still events of randomness at the atomic level that cannot be predicted.
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Analyzing the interactions between and examining the existence of, particles.
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I dont know what dead time is. If you took multiple data points the uncertainty can be related to the statisitcal variance or standard deviation of your data. Maybe you are refering to Heisenberg uncertainty principle where:\ndelta E * delta t greater than or equal to hbar/2
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It means that electrons have both particle-like and wave-like behaviour (for example they demonstrate interference).\n\nwavelength = planck's constant/(mass x velocity)
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The following things are not random, but appear to be:\n\nFlipping coins, throwing dice, the weather, etc.\n\nAll of the above are ruled by the laws of physics. But in those cases, the results might as well be random because the equations governing them are so complex that in practice we can't find exact solutions for them.\n\nHowever, one might ask whether there exist any physical system that it truly random - or do the equations of physics predict exact results for everything? (The only reason we don't know the future, in that case, would be because the equations are too difficult to solve.)\n\nThe answer is actually quite surprizing. Subatomic particles - that is, things smaller than atoms - are truly random. It is impossible, even in principle, to ever calculate what they will do next. All we can do is calculate a probability. That's from an area of physics called Quantum Mechanics. So, in this area of physics, instead of asking a question like, "Where will the particle land?", we ask, "What's the chance of the particle landing over here? Or over there? Or anywhere?" Quantum mechanics produces some truly "spooky" effects - such as the fact that an electron, trapped at the bottom of a bowl, can get out of the bowl without having to get up over the sides! That's a phenomenon known as tunneling, and is due to the fact that there's a small chance of the electron being outside the bowl, even if the electron doesn't have enough energy to get over the walls. That means that it must, at some point, be seen outside the bowl. But it's energy means that it can't go over the walls! So, it basically "teleports" from inside the box to outside the box. There are other quantum mechanical effects due to probability as well - but I'm sure you can find those with a quick internet search...
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>we know that physically one photon can not pass through the two slits at a time\n\nThat's kind of the whole point of considering the single photon case of the double slit experiment: it give results that don't match classical predictions, and so it becomes a good argument for quantum mechanics.  \n\nIf light were a classical particle, then yes, it can't go through both slits, and you'd end up with two overlapping Gaussian bands of light, and not an interference pattern if you summed up the results of many single photon experiments \n\nIf light were a classical wave, you'd get an interference pattern, but you'd expect the energy from it to be spread out all over the detector or photographic plate, just very faint.  \n\nWhat actually happens when this experiment is done is that the energy gets delivered to the detector all in one place, as if light is a classical particle.  But, the locations where the energy gets delivered, if the experiment is done one photon at a time and the results are stacked up, conforms to the interference pattern you'd expect from a classical wave.\n\nSo, we have something that matches neither a classical particle nor a classical wave in  behaviour.  \n\nBut, in quantum mechanics we have a description of something that does fit this behaviour.  That is, we have a wave which, when measured, has to provide energy in quantized steps.  To get from the wavelike portion to the particlelike portion, we have to recognize that there isn't a completely deterministic answer but rather a statistical one.  So, while this model descibes what a real photon does in the double slit experiment, it can't predict the exact behaviour of a specific given photon.  As best we can tell so far, this isn't just a shortcoming of the theory, it's actually how physical reality operates.\n\n\nEdit:  Ramblingman, it can be done with either an electron beam or a photon beam.  Both will show the same sort of effect, but traveling electrons will have a much shorter wavelength than light.  Quantum mechanics works for both things that were classically considered as waves, like photons, and things that were classically considered as particles, like electrons.
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First, can a subatomic particle appear to be in two places at once?\n\nAccording to Quantum Theory, the answer is yes, because in order to know where a particle is, we have to measure its position, but the very act of measuring its position will alter the particle's behavior. So in effect we can never be sure where it is exactly. So in this sense, we may get measurements that give results that says the particle is here and there (this is the Uncertainty Principle).\n\nOf course, this is NOT new to quantum theory. So what's new? Someone mentioned "quantum entanglement" and "quantum teleportation". These are some of the new topics in quantum theory.\n\nPS - there is no such thing as Aether quantum dynamics or\n Auto dynamics, and Bohr's quantum mechanics is alive and well. The only addition we've added to Bohr's theory is the concept of electron cloud (i.e. a probability cloud) around the nucleus of an atom rather than electron orbits.