TimeTraveler Posted December 6, 2004 Posted December 6, 2004 I am writing a philosophy paper about the essence of the universe and the possibility of multiple universes, I need some help with QM. I do not know any of the maths behind Quantum Mechanics or the physics but I sorta understand the "ideas" it proposes, can someone with more knowledge help me out ? Here is a paragraph from my paper and I feel it is flawed but I do not know how to explain it better, remember this is for philosophy. Quantum mechanics is a set of laws that determines the actions of sub-atomic particles. One thing that is interesting is that relativity and quantum mechanics are both laws of physics that explain two separate levels of our universe, however they are connected, should the laws not be the same? Sub-atomic particles have an ability to transmit information instantaneous across the universe, this seems to break the laws of relativity hinting that either, these laws do not conform completely to the essence of nature, or there is a separation in the essence of nature. If the former is true then these laws may provide us with near accurate information but are indeed flawed somewhere. If the latter is true, could this separation in nature be considered as different universes? If I messed it up and offended Quantum Mechanics don't hate me, teach me.
Severian Posted December 6, 2004 Posted December 6, 2004 Lol - only the second sentence is partially true. Sentence 1: QM decribes only a one-particle state. The extension to many particles is Quantum Field Theory. Sentence 2: QM or QFT describes the physics at very small distances, while relativity describes physics at very high speeds. Since very small objects can move very fast, you are correct that they are connected. This is done in relativistic quantum field theory. The problem is how to combine general relativity (ie. gravity) with QFT. Sentence 3. Sub-atomic particles do not transmit information instantaneously. As you point out this would break relativity. Sentences 4 and 5 fall over with Sentence 3...
TimeTraveler Posted December 6, 2004 Author Posted December 6, 2004 Lol - only the second sentence is partially true. I'm only in my first year of physics, anything I have learned about QM I have taught myself, and obviously I shouldn't take up teaching as a career choice. Sentence 1: QM decribes only a one-particle state. The extension to many particles is Quantum Field Theory. Ah yes, I forgot about QFT, I will research this. (as you can see I am not the best self-learner any additional information on how this works would be helpful, I do best when able to ask questions about the parts I do not understand.) Sentence 2: QM or QFT describes the physics at very small distances, while relativity describes physics at very high speeds. Since very small objects can move very fast, you are correct that they are connected. This is done in relativistic quantum field theory. The problem is how to combine general relativity (ie. gravity) with QFT. What about subatomic particles popping in and out of existance? Sentance 3: Sub-atomic particles do not transmit information instantaneously. As you point out this would break relativity. How exactly does this work? I thought there was a connection between particles and other particles on the other side of the universe?
Severian Posted December 6, 2004 Posted December 6, 2004 What about subatomic particles popping in and out of existance? This is included in QFT (but not QM) and has nothing to do with gravity (per se). In fact' date=' this is one of the major differences between QM and QFT. A (virtual) photon for example can turn into an electron positron pair [math']\gamma^* \to e^+e^-[/math], which is a manifestation of QED. How exactly does this work? I thought there was a connection between particles and other particles on the other side of the universe? Although the formulation and evolution of wave equations in QM/QFT is local (ie. to work out what it looks like at time t+dt, you only need to know what it looked like at time t within (c dt) of the point of interest) the collapse of the wavefunction into an eigenstate isn't. To be honest, I don't think this collapse is satisfactoraly described in QM/QFT: it is simply axiomatic in the theory, which I don't like. Anyway, this is intrinsically non-local because a measurement at one point affects the wavefunction instantaneously everywhere, but does not violate relativity since no information is passed at speeds > c.
TimeTraveler Posted December 8, 2004 Author Posted December 8, 2004 Thank you for the help Severian. I still do not quite get it, But I have enough information to know where to look to fill in the gaps.
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