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Apr
28
comment Why do gauge bosons/leptoquarks not mediate proton decay in the Pati-Salam model?
"In Pati-Salam, quarks and leptons belong to different multiplets"... but leptons are just the "fourth color". So an SU(4)-color gluon can change a colored quark to a lepton.
Apr
21
comment Some questions about QCD
@Wein Eld - I thought the problem is to prove that the theory is mathematically well-defined and that it exhibits confinement.
Apr
21
comment Some questions about QCD
Who says solving QCD exactly is a priority? In fact, who is even trying to do that?
Apr
9
comment Membrane Theory
The endpoints of the strings can move on the brane. They have to remain attached, but they aren't stuck to a single point... D in D-brane stands for Dirichlet boundary conditions
Apr
7
asked “Randomness” versus “uncertainty”
Apr
4
comment what is the analog of electronics for quarks or protons?
If a hydrogen atom has one proton in its nucleus, ionize it and you have a proton. So "protonics" can occur in chemistry. But quarks are confined in nucleons, it seems to be hard to do anything with them.
Apr
2
comment It's not the size of your magnet?
@ACuriousMind en.wikipedia.org/wiki/Hardware_disease
Mar
31
awarded  Nice Question
Mar
31
comment Where else than Atoms do Photons Disappear and Reappear from?
OK... "How many ways can photons be made?" Any charged particle can emit or absorb a photon.
Mar
31
comment Where else than Atoms do Photons Disappear and Reappear from?
@Jen why do you want to reopen it?
Mar
26
comment “Why electrons don't fall into nucleus”simple explanation needed
For a deeper theory there is Bohmian mechanics. There is an extra force in Bohmian mechanics called the quantum potential, and it is what opposes the classical electrostatic attraction. No one knows if Bohmian mechanics is the right path behind quantum mechanics and hardly anyone studies it, but it does give a non-probabilistic explanation of why the electron doesn't fall into the nucleus and stay there.
Mar
26
comment “Why electrons don't fall into nucleus”simple explanation needed
In quantum mechanics, there is a wavefunction which gives probabilities for where the electron could be. The wavefunction can't shrink to a point and stay that way, it spreads out again. This is described by Schroedinger's equation. So where the electron might be is always spread out in space.
Mar
24
comment Are there a catalog for various potentials used in inflaton theory, or string theory, or inflation?
arxiv.org/abs/1303.3787
Mar
21
comment If electrons are Bosons?
@KARTHICKP6 Maybe I overstate the importance of the exact value of the spin... The main consequence of electrons being bosons, is that there would be no exclusion principle and so no electron shells. To a first approximation, the wavefunctions of the boson-electrons would all be the same.
Mar
21
comment What came before quantum theory?
The main things that came before quantum theory were Newton's laws and Maxwell's equations. And when you apply those to electrons and nuclei, you get the prediction that atoms are impossible, because electrons would just fall into the nucleus and stay there. Quantum innovations like the uncertainty principle (wavefunctions) and the exclusion principle (fermion statistics) solved this problem, as well as explaining atomic spectra, molecular bonds, and so on.
Mar
21
comment If electrons are Bosons?
An ultimate answer to this question would consider the different cases spin 0, spin 1, spin 2... because those all behave very differently.
Mar
6
comment What's so confusing about quantum physics?
"The fact that we only observe one consistent history of collision is merely due to our perception". This is what many-worlds people say. But they also say there are copies of you in those decohered other histories, who have their own perceptions.
Mar
6
comment What's so confusing about quantum physics?
The Schrödinger equation generates superpositions. If an atom radioactively decays and emits a particle, the wavefunction for the emitted particle is an expanding spherical wavefront. If you take into account collision of the emitted particle with other atoms, you end up with an overall wavefunction consisting of mutually decohered histories of collision. Are you saying that only one of those histories is real?
Mar
6
comment What's so confusing about quantum physics?
"while from our perspective the choice between events/measurements may seem random, it isn't "actually"." You've heard of superposition? The Schrödinger equation is linear. The unobserved branches of the wavefunction do not cease to exist, if its evolution is linear.
Mar
5
answered What's so confusing about quantum physics?