Quantum Mechanics -- Questions?
471221
I am trying to give just a brief idea about these questions. Actual explanations need a lot of space. In any case, one can easily search the internet for these things.\n1. Special theory of relativity was combined with quantum mechanics to produce a new branch of physics called 'relativistic quantum mechanics'. This was done mainly by Dirac. He considered the wave functions of particles moving with very high velocities, and used Lorentz transformation equations in his mathematics. He considered also the imaginary (complex) solutions to the basic equations of motion (such as the Schrodinger equation, for example). The main contribution of this 'unification' was the theoretical discovery of anti-particles (which was varified later on from the experimental discovery of positrons).\n2. The 'unification' of general theory of relativity and quantum mechanics leads to the branch called 'quantum gravity'. The basic problem with this unification is the matching of length scales at which these two theories work. Quantum mechanics is designed and valid for subatomic length-scales, whereas, the general theory of relativity, which is the theory of gravity, deals with massive objects and large (astronomical) length-scales. Presently, scientists are looking for a suitable wavefunction for the universe, which is expected to provide information about the universe in the same way as the wavefunction of an electron gives many information about it.\n3. Feynman reconstructed almost the whole of quantum mechanics and electrodynamics in his own way, deriving a way to analyze atomic interactions through simple diagrams (now known as Feynman diagrams), a method that is still used widely. QED was the theory to which Feynman diagrams were first applied. For his work on quantum electrodynamics, Feynman was one of the recipients of the Nobel Prize in Physics for 1965, along with Julian Schwinger and Shin-Ichiro Tomonaga.\n\nI would also like to comment on the answers given by other users, such as Smart prash: \n1. In question 1 the user is asking about Dirac's relativistic quantum mechanics, and not about Bohr's elementry quanrum mechanics.\n2. Please don't get confused. Quarks are not coloured at all (how can they be?). Colour of a quark is just one of the many quantum numbers that is used in a way to number them in terms of their different energies. Moreover, the question is about QED (quantum electrodynimics), and the colour quantum number is a concept from QCD (quantum chromodynamics).
620171
It is in thoery possible to convert all of the elemental particles into energy and transport that energy to a remote location. The energy could then in theory be reasembeled into particles. However in quantum mechanics there is the priciple of uncertainty. Both the position and momentum of any particle cannot be known with arbitrary certainty. This is not a result of precision measurement more that the particle itself cannot know. So what you put together at the other end will not be the same.
107699
"Quantum mechanics is a physical science dealing with the behaviour of matter and waves on the scale of atoms and subatomic particles. It also forms the basis for the contemporary understanding of how large objects such as stars and galaxies, and cosmological events such as the Big Bang, can be analyzed and explained. Its success is due to its accurate prediction of the physical behaviour of systems, including systems where Newtonian mechanics fails. This difference between the success of classical and quantum mechanics is most often observed in systems at the atomic scale or smaller, or at very low or very high energies, or at extremely low temperatures. Quantum mechanics is the basis of modern developments in chemistry, molecular biology, and electronics, and the foundation for the technology that has transformed the world in the last fifty years."
64985
Quantum Theory, also quantum mechanics, in physics, a theory based on using the concept of the quantum unit to describe the dynamic properties of subatomic particles and the interactions of matter and radiation. The foundation was laid by the German physicist Max Planck, who postulated in 1900 that energy can be emitted or absorbed by matter only in small, discrete units called quanta. Also fundamental to the development of quantum mechanics was the uncertainty principle, formulated by the German physicist Werner Heisenberg in 1927, which states that the position and momentum of a subatomic particle cannot be specified simultaneously.
12701
Quantum Physics would say "no". It was long supposed that once we got down to a certain level, everything would be predictable, but as you may already know, quantum physics doesn't tell us yes or no - it gives us several statistical maybes and such.
498367
A good website on quantum mechanics: http://en.wikipedia.org/wiki/Quantum_mechanics\n\nAlso, if you are intrigued by the cosmological theory of the universe, The Life of the Cosmos by Lee Smolin is an excellent read.
635497
enough to admire it\n\nQM is here to stay like it or not (Einstein did not)\n\nIt is not just a theory but the most provable experimentally modern fundamental theory of the subatomic world.\n\nUnlike the Relativity and other classics theories, it is not a deterministic but "statistical" one. We can know this and that with certain degrees of probability -- that's what QM tells us. It works and that's whats counts at the end\n\n"There is nothing more practical than a GOOD theory."
634237
Ok here is my best explanation of the problem. The Schroedinger's Cat paradox is meant to try and disprove the Uncertainty Principle. This principle stats that particles do not actually have one set state, that they hover in limbo until you observe them. Therefore Schroedinger stated that since you cannot know if the particle decayed until you look does that mean that the cat is in a state or being both alive and dead since the particles decay directly affects the cats life. \n\nThe way I interpret this, being that I believe completely in the quantum theory is that a human need not be the observer once the particle is measured in any way it decides on a state and occupies it. Since the whole cotnraption is dependent on the state of the particle the particle is being measured. During this measurement the particle will "decide" whether it is going to decay or not, and the cat will be affected justly. It doesnt matter that no human has observed it the act of measuring its decay is enough to cause it to shake out of the murky non state and assume a definate state. I hope that helped
93504
The predictions of quantum mechanics are incredible, it is true. Especially in the more extreme reaches, like quantum electrodynamics, and quantum gravity, and quantum chromodynamics, and quantum teleportation, etc. Absolutely amazing. \n\nHowever, as much as these predictions do not agree with our intuition, they have been verified over and over and over for decades and decades. So although it seems like nonsense, it appears to explain what we observe, and to make predictions which we can verify. \n\nSo is it believable? I guess it depends on what you mean by believable. It certainly does not agree with our day to day experiences and intuition. Is it repeatable, and does it make predictions that we find useful? Yes.
43223
Quantum mechanics is a mathematical theory that can describe the behavior of objects that are roughly 10,000,000,000 times smaller than a typical human being. Quantum particles move from one point to another as if they are waves. However, at a detector they always appear as discrete lumps of matter. There is no counterpart to this behavior in the world that we perceive with our own senses. One cannot rely on every-day experience to form some kind of "intuition" of how these objects move. The intuition or "understanding" formed by the study of basic elements of quantum mechanics is essential to grasp the behavior of more complicated quantum systems. \n\n\nPlease visit the below url for moe information
1157167
Quantum Mechanics is the Physics behind Physics, it is Philosophy with Scientifical evidence, this goes beyond Logic and reasoning, and it only goes to show that the most incomprehendible thing about reality,(really is after all) the fact that it is comprehendible!!! I have yet to see the movie but the guy who said he and his chick tried to count how many errors were there within the first 15 minuites of the movie but couldn"t cause there were too many,.. yeah well,... He"s a fool if he disregards all things just as easily as he did this, I mean he counted the errors for example with our common (estimate his knowledge of this topic to a high level by the way, I am willing to assume he knows what he is talking about and what he is talking about is Physics, you know Science science,... I love that subject too,,,, but Quantum Mechanics is a modern Science, even more so and 10 fold than the one used for our latest and most newest forms of technology! \n  Ok please do me a favor and research when this subject first made it"s debut, and more importantly Who helped develop this Topic, and I am sure you will be surprised, For now I will give you one name, and it is one that by the way is not the father of this subject, but Albert Einstein himself, was there when they were cooking this Phenonmenal study up, it was a handfull, I mean a "handfull"! of the best most respectable minds of that time and we should be proud, ........ of our era,.......it brought me peace, when thinking about the Pi equation,...... it doesn"t gibe you an explanation Quantum Mechanics, it hardly gives you an understanding, but you do or can come to terms with the fact that life is not an answer it is a question, perhaps............
16307
Quantum physics is a fundamental physical theory that replaces Newtonian mechanics and classical electromagnetism at the atomic and subatomic levels.  It is the underlying framework of many fields of physics and chemistry, including condensed matter physics, quantum chemistry, and particle physics. Often, it is the answer to questions when general relativity fails.
416146
yes in the quantum world. hey and if no one reads this answer have i really typed it??
697707
Quantum mechanics is fascinating, as Einstein's famous quote that "God does not play dice with the universe" is turned on its head.  The random nature associated with the inner workings of atoms and quarks is astonishing when one considers that despite all of the unpredictability of subatomic activity, things in the macroscopic world follow predictable patterns that seem to defy common sense.
340728
This is one of the best questions i have come across.In fact most Physicists have taken this cue for unravelling the problems of quantum mechanics. Look at the universe. Everything is moving in eleptical orbits. The sea shore is never straight and so are the trees, mountains and the rivers. The big bang and oscillating universe theory talks of tangential motion arrived through circular motion.\nStraightness is unnatiral!
641487
Pauli thru his exclusion principle. For Bosons this is not absolutely true.
261371
It's not that they are at two places at the same time, but there is an equal probability of finding the proton in both places. When you get to the level of quantum mechanics, due to Heisenberg's uncertainty principle we rely on probability curves to get an approximation of the physical world, the funny thing is that the areas with the most probability, are those predicted by Bohr without using quantum mechanics.