Severian Posted June 6, 2005 Share Posted June 6, 2005 A free particle cannot have 0 energy. E2 = m2c4+p2c2, where E is energy, p is (three-)momentum and m is mass. To have E=0, you would have to have m=0. But a massless particle such as a photon have E=hf where f is the frequency of the wave, so E=0 implies a wave with zero frequency, which is unphysical (actually it can be subtracted off). Link to comment Share on other sites More sharing options...
5614 Posted June 7, 2005 Share Posted June 7, 2005 OK, so free particles cannot have e=0 but we can always add a potential energy allowing e=0 So is ZPE always zero because you can always apply a potential? Link to comment Share on other sites More sharing options...
Tom Mattson Posted June 7, 2005 Share Posted June 7, 2005 A free particle cannot have 0 energy. E2 = m2c4+p2c2' date=' where E is energy, p is (three-)momentum and m is mass. [/quote'] But that relation has the potential V set equal to zero by hand, does it not? The same dynamics of a free particle follow from V=(constant). So if I replace E with E+V, V=constant, and put it into the relation above I obtain: E2+2EV+V2=m2c4+p2c2 E2=m2c4+p2c2-2EV-V2 If I set E=0 then I have: V2-(m2c4+p2c2)=0, which has 2 real solutions for V. Link to comment Share on other sites More sharing options...
Tom Mattson Posted June 8, 2005 Share Posted June 8, 2005 Oops, never mind. The solutions to the above equation will indeed make E=0, but E is not the energy of the particle anymore. E*=E+V is the energy, and that is not zero. Link to comment Share on other sites More sharing options...
zelcon Posted June 25, 2005 Share Posted June 25, 2005 Dude, Particles have mass. According to Einstein's theory of general relativity, mass and energy are interchangable aspects. Hence, there is no such thing as a 0 energy particle. P.S.: Sorry, I didn't read all the other posts, they say just what I said!!! Link to comment Share on other sites More sharing options...
5614 Posted June 25, 2005 Share Posted June 25, 2005 Can I re-ask these two questions from post #27: OK, so free particles cannot have e=0 but we can always add a potential energy allowing e=0 So is ZPE always zero because you can always apply a potential? Link to comment Share on other sites More sharing options...
zelcon Posted June 25, 2005 Share Posted June 25, 2005 5614: I would say yes, but don't take my word for it. Link to comment Share on other sites More sharing options...
charm quark Posted July 17, 2005 Share Posted July 17, 2005 This is such a great topic and I only can put my one piece of information mass-energy sequence.This among other topics show great simplistic abscurity! I love science! Link to comment Share on other sites More sharing options...
DQW Posted July 17, 2005 Share Posted July 17, 2005 Can I re-ask these two questions from post #27: OK' date=' so free particles cannot have e=0 but we can always add a potential energy allowing e=0 [/quote']Yes, though this would make little "sense" and really, serve no purpose. And it would be quite confusing - non-interacting particles would have negative potential energy (put in by hand). So is ZPE always zero because you can always apply a potential? See above. Link to comment Share on other sites More sharing options...
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