Recent content by jncarter

  1. J

    Finding the Quantum States for a Nitrogen Atom

    To find the number of possible configurations you need to do some counting. There are formulas out there to do this for a given electron configuration (see Introduction to Quantum Mechanics by Griffiths). Let's start with an example. For atomic hydrogen you have one electron in configuration...
  2. J

    Particle Behavior in Double Slit

    The answer to this question isn't really known. It is more of a matter of philosophy. Do you choose to believe that the electron is a particle that we can touch and see that goes through both, neither and one slit all at once? Or do you simply believe that we can only represent to electron as a...
  3. J

    Partition function to find expected occupancy of a lattice defect

    Homework Statement An impurity can be occupied by 0, 1 or 2 electrons. The impurity orbital in non-degenerate, except for the choice of electron spin. The energy of the impurity level is \epsilon, but to place the second electron on the site requires an additional energy \delta \epsilon...
  4. J

    Two oscillating masses on springs in one dimension

    Include a phase factor in your solution. x_{1} = A*e^{i (\omega t +\delta_{1})} Similarly for the second wave vector. Now retain the amplitude relationships and use the phase factor \delta to allow for zero values at time t=0. It may be more useful to use sine or cosine functions at this point...
  5. J

    Two oscillating masses on springs in one dimension

    This type of problem is much easier to do using Lagrangian mechanics. Are you familiar with this method? You could also set this up as an eigenvalue problem. You would use \omega^{2} as your eigenvalue and x_{1}, x_{2} as your eigenvector. You should find that there are two very distinct modes...
  6. J

    Bose-Einstein Condensation & de Broglie wavelength

    Homework Statement Bose-Einstein condensation of a fluid occurs when the de Broglie wavelength of a "typical" particle becomes greater than the average nearest-neighbor distance. One can interpret the momentum in the de Broglie equation as p=\sqrt{<p^{2}>} where <p^{2}> means the thermal...
  7. J

    Hypergeometric equation at z = infinity

    You're right about that second equation. That was my bad forgetting parentheses. I also got the chance to talk to my TA yesterday, and you're right about the second derivative. Thanks for all the help. There's just so much algebra with this type of problem, it's easy to lose track of things.
  8. J

    Hypergeometric equation at z = infinity

    You lost a negative sign \frac{du}{dz} = -\alpha \zeta^{\alpha+1}v- \zeta^{\alpha+2}v' I haven't checked the other part of your work yet. My last post may also be wrong. I found this formula somewhere \frac{d^2}{dx^2}(uv) = \frac{d^2 u}{dx^2}v+2\frac{du}{dx}\frac{dv}{dx}+u\frac{d^2 v}{dx^2}...
  9. J

    Hypergeometric equation at z = infinity

    Okay, new attempt at the second derivative: \frac{d^2}{dz^2}(z^{-1})=2z^{-3}=2\zeta^{3} \frac{d^2}{d\zeta^2}(\zeta^{\alpha}v) = v\frac{d^2}{d\zeta^2}(\zeta^{\alpha}) + \zeta^{\alpha} \frac{d^2v}{d\zeta^2} \rightarrow = \alpha(\alpha-1)\zeta^{\alpha-2}v+\zeta^{\alpha}\frac{d^2v}{d\zeta^2}...
  10. J

    Hypergeometric equation at z = infinity

    Oops, u = \zeta^{\alpha}v. \zeta = z^{-1} → d\zeta = -z^{-2}dz=-\zeta^{2} → \frac{d\zeta}{dz}=-\zeta^{2} Note the positive in the \zeta], since z has a negative exponent, \zeta has a positive one. \frac{du}{dz}=\frac{du}{d\zeta} \frac{d\zeta}{dz} = -\zeta^{2}\frac{d}{d\zeta}(\zeta^{\alpha})...
  11. J

    Hypergeometric equation at z = infinity

    Homework Statement Show that by letting z = \zeta^-1 and u = \zeta^{\alpha}v(\zeta) that the differential equation, z(1-z)\frac{d^{2}u(z)}{d^{2}z}+{\gamma - (\alpha+\beta+1)z}\frac{du(z)}{dz}-\alpha \beta u(z) = 0 can be reduced to \zeta(1-\zeta)\frac{d^{2}v(\zeta)}{d\zeta^{2}} +...
  12. J

    How Do You Calculate the Center of Mass for an Isosceles Triangle?

    Homework Statement Find the center of mass of a triangle with two equal sides of length a. The triangle's third side is length b and it has a uniform mass of M. Homework Equations R = \frac{1}{M} \int dm \vec{r} dm = \frac{M}{A} A = \frac{1}{2}base*height The Attempt at a Solution...
  13. J

    Contour integral with exponential in the denominator

    Homework Statement Use the contour integral \int_{C}\frac{e^{pz}}{1+e^z}dz to evaluate the real integral \int^{\infty}_{- \infty}\frac{e^{px}}{1+e^x}dx 0<p<1 The contour is attached. It is a closed rectangle in the positive half of the complex plane. It height is 2i∏. Homework...
  14. J

    What is the Frequency of Oscillation for a Gibbon Hanging on a Tree Branch?

    Have you tried solving the problem yet? We need to know where you are having difficulty before trying to help. In other words: Show us your work.
  15. J

    Alternating linear chain of masses

    When I took the derivatives more carefully I ended up with the same x-equation, but the y-equation come out as m\ddot{y_{n}} = 2ky_{n} - k(x_{n} + x_{n+1}) My professor pointed out that this is not a restoring force. The yn term needs to be negative, but he says the potential looks like it's...
Back
Top