Recent content by Malamala

  1. M

    A Advice for 100 MHz resonator

    I don't have a design yet, I am in the design phase. I am thinking of a measurement, and I did all the math, but this kind of magnetic field is the main systematic. So before deciding if I should pursue this idea, I would like to know if it is even possible at all to achieve this. At this point...
  2. M

    A Getting the power spectral density from a plot

    I am using python. Welch method is built it, but it has this parameter which defines how many points I have in each segment and the obtained PSD changes visually based on that. And it only looks like what I would expect, based on other papers, only when I include all the points in my data set in...
  3. M

    A Getting the power spectral density from a plot

    Hello! I have some time series from a self-heterodyne measurement. Basically i have a laser and I combine it with a delayed version of itself, shifted by ##\Omega = 2\pi \times 80## MHz. The delay is ##\tau = 100##ns. I remove the DC so the signal from the beat note is: $$V(t) = V_0\cos(\Omega...
  4. M

    A Confused about noise power spectral density measurement

    Hello! My question was started from this paper. The topic of the paper is related to linewidth measurements, but my question is even before that, related to the way the noise power spectral density (PSD) spectrum shown in Fig. 1 is obtained. In Fig. 2 they show their experimental setup, which is...
  5. M

    I Matrix element involving raising/lowering operators

    What I meant was that after you suggested that commutativity might be the issue I tried that and I still didn't get ##-\sqrt{2/3}##, which I should. What I did was to apply the operator to the left which becomes: $$(<0,0|Y_1^{-1})N_+ = (<0,0|N_+)Y_1^{-1} + <0,0|(Y_1^{-1}N_+) =...
  6. M

    I Matrix element involving raising/lowering operators

    No, sorry for the confusion. I don't have independent information. I know it's not correct as the 2 answers should agree (I don't know to what value, but that value should be the same for both). So the fact that they still don't agree, even after using the non-commutativity, means that I still...
  7. M

    I Matrix element involving raising/lowering operators

    Yes, but if I assume commutativity, I still don't get the right answer (it's non-zero, but still not right).
  8. M

    I Matrix element involving raising/lowering operators

    But what should I do then? I assume that there should be a definite value for that matrix element, but I am not sure how to compute it.
  9. M

    I Matrix element involving raising/lowering operators

    Hello! I have this operator ##Y_1^1(\theta,\phi)N_-##, where ##N_-## is the lowering operator for ##|l,m>##. I want to calculate: ##<0,0|Y_1^1(\theta,\phi)N_-|1,0>## and I am getting: $$<0,0|Y_1^1(\theta,\phi)N_-|1,0> = \sqrt{2}<0,0|Y_1^1(\theta,\phi)|1,-1> = \sqrt{2}\int...
  10. M

    A Power spectral density of a laser's frequency noise

    Uhh... I am still confused... if i measure the PSD experimentally using the self-heterodyne method, what would I see? Would I see 1/f + white noise, as in the first paper, or the Lorentzian shape as in the second paper? Also, it's still not clear to me how the length of the line matters i.e...
  11. M

    A Power spectral density of a laser's frequency noise

    But I guess my main question is: does the different shape come only from the longer delay? And if I make the fiber longer, would that beta-line method still work at all, given that the spectrum shape would be completely different? What exactly do you mean by "phase noise that varies more...
  12. M

    A Power spectral density of a laser's frequency noise

    Hello! I am a bit confused about what power spectral density (PSD) is in the context of a laser. In particular, I came across this paper. In Fig. 1 they show PSD vs frequency. As far as I understand, PSD is just the square of the FT spectrum of a laser frequency/phase as a function of time...
  13. M

    I Confused about a matrix element

    Hello! My questions is in the context of a matrix element in a diatomic molecule. I will rephrase it as well as I can to remove any non needed complexity. I denote the sperical harmonic ##Y_m^l = |m,l>##. I have the operators ##n_{0} = Y_1^0## and ##n_{\pm 1} = Y_1^{\pm 1}##. I also define the...
  14. M

    I Magnetic field inside a capacitor

    Thanks a lot for this! But I actually got confused by the last sentence. Are you saying that indeed the magnetic field is zero in between the 2 plates (is this what you meant by "nor within the dielectric.")? And it becomes non-zero only outside?
  15. M

    I Magnetic field inside a capacitor

    Sorry I am not sure what you mean by this reply. I agree with your derivations, but I still don't see why the magnetic field can't be identically zero.
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