Recent content by jsc314159

  1. J

    Understanding the Total Energy of a Hamiltonian

    Correct, x' is a function of x and t in a coordinate system moving with the cart. However, in this coordinate system H is no longer an explicit function of t.
  2. J

    Understanding the Total Energy of a Hamiltonian

    So in the case of the spring-mass on a cart moving with uniform velocity, which has time varying constraints, H can be represented as: H = \frac{p^2}{2m} + \frac{k}{2} (x - v_0t)^2 if the generalized coordinate is the position x of the mass. In this case H is the total energy...
  3. J

    Understanding the Total Energy of a Hamiltonian

    So, if H is in a form H = T + V, H represents the total energy. However, if H is not in this form, like in the case of a charged particle moving in a magnetic field or in the case of time varying constraints, then H is not the total energy. Is this right? I suppose I am somewhat confused over...
  4. J

    Understanding the Total Energy of a Hamiltonian

    I have a question on the Hamiltonian from a classical viewpoint. I understand that the Hamiltonian, H, is conserved if it has no explicit time dependence, in other words: \frac{\partial H}{\partial t} = 0 What I am not clear on is how one can determine whether a given Hamiltonian...
  5. J

    What is the meaning of the lower case i in the Schrodinger equation?

    The Schrodinger equation is a form of the wave equation. It can be interpreted like a wave equation. The acceleration at each point on the wave function is due to the Hamiltonian and that the larger the concavity of the wavefunction at point, the larger the acceleration. Does that make...
  6. J

    Photoelectic cross-section question

    I think the reason a_0 -> a_0/Z is because the Coulomb potential in the Hamiltonian changes from q^2/r to Zq^2/r . Is that right? jsc
  7. J

    Why there is no isotope of hydrogen with an atomic weight of four?

    Do you mean hydrogen with a nucleus of 1 proton and 3 neutrons? Tritium is a radioactive isotope of hydrogen with 1 proton and 2 neutrons. It usually decays via H^3 -> (He^3)^+ + e^- + \nu^- Perhaps H^4 would be unstable due to internuclear forces. jsc
  8. J

    Photoelectic cross-section question

    Homework Statement Show that if we consider photoemission from the 1s state of a charge Z atom, \sigma \propto Z^5}} , in the limit p_fa_0/Z\hbar >> 1. Homework Equations \sigma = \frac{128a_0^3\pi e^2p_f^3}{3m\hbar^3\omegac[1+p_f^2a_0^2/\hbar^2]^4}} The Attempt at a Solution Actually...
  9. J

    Sudden Perturbation Approximation Question

    Thanks nrged. That makes it clear.
  10. J

    Sudden Perturbation Approximation Question

    Homework Statement In a beta decay H3 -> He3+, use the sudden perturbation approximation to determine the probability of that an electron initially in the 1s state of H3 will end up in the |n=16,l=3,m=0> state of He3+ Homework Equations |<n'l'm'|nlm>|^2 The Attempt at a Solution...
  11. J

    Exploring the Inter-Relationship of Nature's Constants

    Sorry, I didn't know a thread already existed on this topic. I suppose that is what the search function for. jsc
  12. J

    Exploring the Inter-Relationship of Nature's Constants

    Hello all. I only have a few posts here so I am somewhat new to the forum. I have been reading a number of the posts though and I am favorably impressed by many of the responses. I am also somewhat new to LaTex so please forgive my mistakes with it. I am interested in learning more about the...
  13. J

    Understanding the Uncertainty Principle

    The rabbit hole gets deeper. Besides x and p, t and E also have an associated uncertainty in QM. \Delta t * \Delta E \geq \hbar/2. From what I understand about this, it means that there is a finite limit on how well we can know the energy of a particle that has existed for a finite...
  14. J

    QM: Angular Momentum-Wavefunction "psi" & Schrodinger's Eq.

    I will keep that in mind. Thanks again.
  15. J

    QM: Angular Momentum-Wavefunction "psi" & Schrodinger's Eq.

    kdv, Thanks, that is the solution. How can I learn to see these types of things more effectively? jsc
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