Recent content by dicerandom

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    Schools Anybody wanna give me some advice on grad school in general?

    I can't reccomend a school for you since condensed matter isn't my area of interest and I don't know much about where the active research is, but I can tell you that it's probably a good field to get into if you're interested in it. There are a lot of jobs in industry working on condensed...
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    How should we convey curved space-time?

    The misconception is easy enough to clear up, just explain that the natural extension of "curved" into arbitrary spaces is that straight lines which were parallel at some point deviate from one another. This also provides a good example of curvature near the Earth's surface, which people might...
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    For proton and electron of identical energy encounter same potential

    That depends on the exact height and length of the barrier as well as the energy of the incident particles. For a given height and length of the barrier you can find an energy less than the height of the barrier for which either particle would have a transmission probability of 1 and the other...
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    Do I really need physics for Computers?

    Ask yourself this: What are the vast majority of supercomputers used for? The answer is "physics" :wink:
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    Einstein: Could he have been the father of QM?

    Most of the books I've read give Einstein a fair bit of credit for his work on the photoelectric effect. Of course, as seems typical in science, QM didn't really have a single "father", there were many people who contributed various pieces to its development over a period of many years. I...
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    How should we convey curved space-time?

    Of course the surface of the apple is really just a closed rubber sheet :wink: When trying to work out (or explain) various curved-space concepts I usually fall back to the surface of a sphere. It's a simple curved space that I'm very familiar with and can easily visualize myself walking...
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    Can We Define the Size of an Electron Theoretically or Experimentally?

    In Physics, "Classical" usually means "wrong" :wink: Nobody is saying that we should be modeling the electron as a rotating sphere. Every professor in every quantum mechanics course I've ever taken has made sure to explicitly state that is not the case, as a matter of fact. What they're...
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    3D harmonic oscillator ground state

    You can prove it using the raising and lowering operators and the Dirac formalism without ever having to write down a wave function. Wikipedia covers it in a section of their Quantum harmonic oscillator article, for more detail there's also some...
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    Schwarzschild radius of a black hole

    The r value of the Schwarzschild radius is the coordinate r, not the "real" r (straight-line-path distance from the center). The coordinate r value does not depend on the curvature of the local spacetime, it's just some grid that an observer out at infinity laid down. Edit: Somewhat unrelated...
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    3D harmonic oscillator ground state

    D'oh! I got caught up with the 1D idea and forgot to use the spherical differential volume element. Nevermind, back to the drawing board.
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    Zero Torque and static equilibrium

    Draw a force body diagram. The stick is just sitting there so the sum of the forces in each direction must be zero and the sum of the torques must be zero.
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    Orbital Radius of Earth Satellite: Solve for r

    You need to use the value of T in seconds for the constants you used to be correct.
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    Are Linear Operators Commutative When They Share Common Eigen Vectors?

    Hint: write it out. And remember to watch out for which side you're multiplying on with A or B since, in general, AB \neq BA.
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    3D harmonic oscillator ground state

    OK, I've been scratching my head over this for a while now and I think I've figured it out. I noticed one problem, in that when you did your first simplification of the SE your term for the radial derivative is incorrect, it should be the same as the first term in the Laplacian you posted...
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    Understanding Spacetime Geometry: Timelike and Spacelike Vectors Explained

    I don't believe you can download them legally, it's something you're supposed to buy.
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