Can you explain the Schroedinger's cat paradox?
96586
First of you should go and order or find a copy of Schroedingers cat by Robert Anton Wilson.\nAmazon-Schrodinger's Cat Trilogy : "The Universe Next Door", "The Trick Top Hat", & "The Homing Pigeons" (Paperback)\n\nBasically it's this-\n\nThere is a cat inside a closed box and inside the box with\nthe cat is a radioactive isotope.The box is closed and nobody knows whether the isotope has silently exploded killing the cat or is still in it's normal state.The symbology behind this is that nobody real knows whether the cat is dead or alive.Lets just say also in case you where wondering that nobody is touching or moving the box.\n\n     Now- In al reality in your mind you may think the cat is dead and someone else may think the cat is dead and neither of you really know.You may even say "Well one of us has to be right "And one of us has to be wrong" So you are both percieving seperate realities.And there is actually no "Dead/Alive" absolute.Science and nature don't work in absolutes.And in truth both realties exist at the same time.
768519
The law applies itself on isolated systems exclusively in contact with others (or different parts of the same isolated system).Some researchers suggest that the universe is not a closed system, although the Sun and planets in our solar system are often treated as an isolated system, this is an idealization because real life isolated system do not exist but behave like this for a finite time. Regarding reversability, physics has "Loschmidt's paradox, also known as the reversibility paradox,[which] is the objection that it should not be possible to deduce an irreversible process from time-symmetric dynamics. This puts the time reversal symmetry of (almost) all known low-level fundamental physical processes at odds with any attempt to infer from them the second law of thermodynamics which describes the behaviour of macroscopic systems. Both of these are well-accepted principles in physics, with sound observational and theoretical support, yet they seem to be in conflict; hence the paradox."
922361
That was the theory, for a little while.\n\nThen they did this experiment and the universe proved to be really, really creepy because electrons still act like waves when there are no other electrons to repel:\n\nhttp://quantumiscool1.ytmnd.com/\nhttp://quantumiscool2.ytmnd.com/\nhttp://quantumiscool3.ytmnd.com/\nhttp://quantumiscool4.ytmnd.com/\n\nThey are YTMNDs, but the facts are right and in a form comprehensible to mortals. Its so weird and creepy you just have to watch this and I won't even try to explain it.
859522
i don't know if there is a "solution" to the paradox. seems liek there is only and "understanding" of the paradox.\n\nhope this helps in your understanding:\n\nhttp://en.wikipedia.org/wiki/Monty_Hall_problem
407070
The short answer is that it simply isn't derived. \n\nStandard quantum mechanics is based on a series of postulates which describe something called a wavefunction. One of the postulates states that the wavefunction must obey the Schrodinger Equation.\n\nThe Schrodinger Equation is somewhat analogous to F=MA (Newton's Second Law) from classical mechanics. There really isn't any derivation of F=MA, it just seems to work. If you are doing an experiment with classical mechanics and you plug the right numbers into F=MA, you get the right answer. Likewise with the Schrodinger Equation, except it works on the quantum scale.\n\nThere have been some attempts to derive the Schrodinger Equation from a grand unified field theory, but for all but the most advanced particle physics applications the Schrodinger Equation is simply taken as a postulate. (just like F=MA)
648975
Schroedinger's cat. \n\nYour recollection isn't very clear, but if you put "Schroedinger's cat" into Google you will many thousands of good explanations.
32300
sure.  the thing about entangled states is that while the state may collapse "instantaneously", that doesn't mean that information is necessarily transmitted.\n\nconsider 2 atoms in an entangled state.  alice takes one, and bob takes the other and gets on a rocket ship and flies to pluto.  when he gets there, he radios back to earth "ok, alice, i'm here!" and waits the 7 hours or whatever it takes for a response to come back at the speed of light.\n\nso once alice and bob get all settled, alice performs a measurement on her part of the entangled pair.  she gets |0> (in qubit notation) or whatever the state is, with a certain probability - say, 50%.  since alice and bob have agreed on a pre-determined time to do this, 10 minutes later bob measures his state.  \n\nnow, because the quantum system collapsed from a mixed state to an eigenstate when alice did the measurement, that means bob's state instantly collapsed too.  but bob has no *a priori* knowledge of what alice measured!  alice's measurement came with some certain statistical probability, and when bob does his measurement, he will get a result with the same probability, since his mixed state collapsed too.  so bob measures a |1> because alice already measured a zero, but he has no way of knowing what outcome to expect before the measurement.  so to bob, the result is a random outcome as well.\n\nthe point is that alice cannot *control* the outcome of her experiment - all she can do is measure it because of the random nature of quantum mechanical systems.  \n\nif alice were to perform her measurement, and then radio ahead to bob and say "hey bob, i got |0>" then bob could be certain that when he measures his state, he gets |1>.  but now information has not traveled any faster than the speed of light, for this is "classical" information traveling by radio.\n\nso, anyway, there you go.  this is a rather simplified and not very clear explanation.  this seeming paradox is called the "EPR paradox" after einstein, podolsky and rosen who considered its ramifications.  you can read more about it here:\nhttp://www.physlink.com/Education/AskExperts/ae634.cfm\nhttp://math.ucr.edu/home/baez/physics/Quantum/bells_inequality.html\nhttp://en.wikipedia.org/wiki/EPR_paradox
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I like your question and hope it is one that you yourself thought up rather than someone handing you and expecting some pat answer back. \n\nThe difficulty we have in answering it is the word "entity." In our ordinary world, a door is an entity so is a kitten. When a kitten jumps through a door, there is no chance that the kitten will go through the door and come out as a rain of kittens (diffracting) with a solid seeming kitten in the center and some ghostly kittens further out. And yet, photons do that.\n\nWe allow photons to travel at the speed of light in a vacuum. Nothing else is allowed to do that. Hard to talk of entity with that exception given to it. \n\nI am not sure, even though I teach about photons, that we can talk very concretely about them as entities. Mathematical conveniences? Convenient? Had to learn a whole new way of doing math but yes, I guess. Information carriers might be an interesting way of putting it, too, in a Feinnman sort of way.\n\nNow I will be thinking about this all day. Good question.
892822
(1) there is no problem with the concept\n\n(2) the concept refers not to "a wave of particle". But to the fact that the wave IS the particle, and the particle IS the wave.  More precisely, the particle (in our everyday definition, i.e. a small bit of matter) does not really exist at a precise point in space, but it is to be found in a given region, and the probability of finding it there is proportional to the absolute value of its "wave function"\n\nyou seem to view this as little bits of matter / light undulating on top of a wave - that's wrong.\n\n\nhistorically, what happened is that various experiments seemed to suggest that SOMETIMES it seemed that you had a wave, and other times, a particle.\n\nThe most famous one is the double slot experiment.  Incoming light will go through the two slots, and lights re-emitted after having gone through each slot will interfere with each other, and on a screen you will observe an interference pattern, i.e. a series of bright and dark bands.\n\nso then someone suggested to use light of such low intensity so that you'd literally emit one photon at a time.  Hoping to not get any interference picture - since each photon could not interfere with anything.\n\nbut what happened was that the photons would arrive at various points on the screen, and little by little, their accumulation would reconstruct the interference picture\n\nthis is what caused people problems - until they invested quantum physics, which deals perfectly with this.
305772
Seems to me that if you can manipulate 2 particles into entanglement (let's say one in New York, one in LA), then you can also manipulate a third particle (in Chicago) to the qualities measured in the first.  Sorry mathematician, but your two/three particle wave function theory although fascinating doesn't apply
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The famous Young's Double Slit Experiment with electrons.\n\nIf you shoot electrons through two thin small slits, they will exhibit an interference pattern like that of light on the screen.  This means the electrons will only hit the screen where there would be a bright fringe, and they won't hit where there would be a dark fringe.\n\nThe quantum behavior is the electrons behaving like a way instead of a particle.\n\nThe explanation to this is quite amazing.  According to the quantum theory, each electron goes through both slits at the same time, which is how it "knows" there are two slits.  If you were to close one of the slits, the electrons would create an interference pattern on the screen that light would make with one slit.  \n\nThen, if you open the second slit, the pattern changes back to that of a double slit experiment.  Feynman developed what is known as the sum of histories to explain this.  It says the electron takes every probable path on its way to through the slits to the screen, which is how it goes through both slits, and how it "knows" the interference pattern to create so to speak.  \n\nThe cool thing is, every object obeys this sum of histories.  Why don't cannon balls take every probably path when it is shot at an angle?  The cannon ball will take the same parabolic path everytime.  So, it seems this sum of histories doesn't work for large objects.  The cool thing is it does!\n\nWhen you use the mathematics involved in the sum of histories, all paths cancel or drop to a zero probability except for the parabolic path the cannon ball takes.  The reason: it is too large, and thus the quantum affects don't apply.  But, when dealing with the very small, such as electrons, the all possible paths have a non-zero probability.
664927
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.
184617
Did a teacher tell you this and now you wonder?  Or is this a mathematical riddle?\n\nIf the former, I don't see the inconsistency.  If the latter, I can't wait for the punchline.
870020
While photons don't have any force-mitigated interactions, there can be interference.  Matter (fermions) has the Pauli Exclusion Priniciple preventing, say, two electrons from being in the same spin-state in the same sub-orbital...there's a destructive interference term in the probability wave equation that comes from their half-spin states.  \n\nSimilarly, there's an inverse sort of "Pauli Inclusion Principle" for bosons (which have integral spin states and includes photons) to constructively interfere in the wave equation such that there's an increased probability for them to be in the same place at the same time.  \n\nOne might be able to, as you say, 'channel' this and force them to work together by creating an energetic population inversion of electrons ready to emit, then sending through a photon of the proper wavelength to produce a cascade of stimulated emission...Oh wait, that's a laser.
1093639
What meant Indeed ?\n\nIt is not a easy question. This question was originally highlighted by Niels Bohr in the Copenhagen interpretation, where a system stops being a superposition of states and becomes either one or the other when an observation takes place. This makes apparent the fact that the nature of measurement, or observation, is not well defined. In other words we can measure position, but not the velocity or we can measure velocity, but not the position. \n\nI did mention Schrödinger's cat did not I? The Schrödinger's cat paradox suggests that by the act of quantum measurement we are destroying the object of measurement and hopefully not before we obtain one particular property. \nhttp://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat  \n\nSo by ‘measurement’ in QM we mean “In classical physics the mathematical model talks about the things we observe. In QM the mathematical model by itself never produces observations. We must interpret the wave function in order to relate it to experimental observations.” http://www.mtnmath.com/faq/meas-qm-2.html   \n\nI hope that tickles you, but I suspect you knew the answer.
51835
The physics community thinks not, but that never proved anything. The assumption is that nothing can travel faster than light. The answers are usually along the lines of, "since quantum entanglement happens instantaneously, its faster than light, but nothing can travel faster than light, so its impossible".\n\nThere may come a future theoretical structure in which lightspeed is surpassed under some circumstances, without temporal repercussions, then this assumption does not hold.\n\nI would add that I think its possible, based on an experiment described in Brian Greenes fabric of the universe that he uses to explain that its not.\n\nIts a simple extension of the two slit experiment where, immediately after the slits you use a photon doubler to create two entangled photons for each one passing through the slits. One for each slit. One photon carries on, the other is bent off at 90 degrees using a half silvered mirror and sent a long distance.\n\nIf no measurement is made on this second photon,, the other photons act as waves and you get an interference pattern. If a measurement is made, they act as particles and you get hotspots behind each slit.\n\nMy extension is that, by choosing to measure the photons that travel a long distance, you can instantaneous make the photons produce an interference pattern or not. Such a pattern would be noticable. If the split photons have travelled many light years, this pattern should be formable in a few seconds, so the message is coded in interference / non interference. Much like morse code in dots and dashes.
63744
B only seems impossible because you're looking at it from a small, everyday perspective.  Read a book on quantum phenomenon and you'll discover that particles literally appear out of no where everyday, and we take this as completely normal.  The Universe and Everything is far more sophisticated than you're giving it credit for.