Recent content by tnho

  1. T

    Can photons create their own gravity?

    To be a bit clearer "photon has zero rest mass, which is the mass we measured in its co-moving frame although it is not possible to do so. In general, photon do has mass which is due to its momentum, namely E=pc . With non-zero mass, there should have non-zero gravity created. Here i have a...
  2. T

    Minimum Proton Energy for Producing Antiprotons

    Yes. I think so. The sum of linear momentum of the particles is zero in the centre of mass frame in SR.
  3. T

    When Does Helmholtz Free Energy Decrease?

    I bet it should be 0.5\rho g h^2 - \frac{k_B T}{A}\log(h). =P It is a very good example~thank you~
  4. T

    Minimum Proton Energy for Producing Antiprotons

    See if i have done anything wrong or not~ First do it in the frame where the target proton (marked 2 below) is stationary. P_1 = (E_1/c,p_1,0,0) \mbox{ ; } P_2 = (mc,0,0,0) By conservation of four-momentum, P_1 + P_2 = P_3 + P_4 +P_5 +P_6 (P_1 + P_2)^2 = (P_3 + P_4 +P_5 +P_6)^2 (P_1...
  5. T

    Minimum Proton Energy for Producing Antiprotons

    I think you may try to use four-momentum vector approach. This will never wrong~ and i think the answer is something like 7m_p c^2
  6. T

    Solve Evolution Operator: <J|U|E>=Exp[-iEt/h]*<J|E>??

    It's a very useful trick~try to make good use of it~
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    What is the approximate quantum number of the electron?

    \frac{1}{2}mv^2 = \frac{n^{2}\pi^{2}\hbar^{2}}{2mL^{2}} then n=\frac{mvL}{\pi \hbar} put m=9\times 10^{-31}, v=3\times 10^{4}, L=48.5\times 10^{-9} \mbox{ and } \hbar = 1.055\times 10^{-34} then you can get n\approx 4 get it?
  8. T

    Solve Evolution Operator: <J|U|E>=Exp[-iEt/h]*<J|E>??

    what is that "*" mean? complex conjugate (cc)?? or just multiplication? Use e^{x}=\sum_n x^n/n! and H|E\rangle = E|E\rangle then you can get that equation. I think that "*" is just a multiplication instead of a cc. :smile:
  9. T

    What is the approximate quantum number of the electron?

    yes. I got 3.969 for using E_n=\frac{1}{2}mv^2. Besides, E_{n} = \frac{n^{2}\pi^{2}\hbar^{2}}{2mL^{2}} is a result from Schrodinger Equation which is non-relativistic. I am not sure if this form preserve in Dirac Equation or not.
  10. T

    One dimensional infinite potential well problem

    the |phi> is the excited states in the new potential, right??
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    Why Should Load Reactance Match Generator Reactance for Maximum Power Transfer?

    Homework Statement An alternating current electrical generator has a fixed internal impedance R_{g}+iX_{g} and is used to supply power to a passive load that has an impedance R_{g} +iX_{l}, where i = \sqrt{-1}, R_{g}\neq 0, and X_{g} \neq 0 . For maximum power transfer between the generator...
  12. T

    Solving the Solar Neutrino Problem

    I have thought that before but not quite sure. It is true that oscillation angles do depend on energy. um..i don't think so as those experiments only measured the electron neutrinos but no other flavors.
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    Solving the Solar Neutrino Problem

    You are right. Neutrinos DO change their flavors (or states). However, all experiments mentioned above were all observing the electron neutrinos with the same length traveled.
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    Solving the Solar Neutrino Problem

    In the solar neutrino experiments, there were deficits in the observed solar neutrino flux when compared with the theoretical values. If i just focus on the Cl-37 and Ga-71 reactions to detect solar neutrinos, there is a question confuses me a lot. That is, from the result of experiment...
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    Relativistic electromagnetism problem

    i think it would be much better if you can translate your .tex file into English...:cool:
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