Recent content by quantumkiko

  1. Q

    The Multiversians are at the gates

    I agree with the above quote and most of what you've said in this forum regarding science. I remember watching a video about Dark Matter by Arkani-Hamed during the part when he was showing both the theoretical and observed rotational curves. He goes on to say that if the results don't agree or...
  2. Q

    Representation of Dirac-delta function

    Homework Statement Show that \delta_\epsilon(x) = \frac{\epsilon}{\pi (x^2 + \epsilon^2)} is a representation of the Dirac delta function. Homework Equations I already know how the function can satisfy the first two requirements of being a dirac delta function, namely...
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    How to find suitable exercises to practice on (in physics geometry) ?

    I suggest "Classical Mathematical Physics" by Walter Thirring. https://www.amazon.com/dp/0387406158/?tag=pfamazon01-20 The book is dense but makes up with the rigor by providing lots of diagrams and examples. It contains problems and solutions to all the problems. Pretty amazing book if you...
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    Spectroscopy via diffraction gratings with different spacings

    Thank you! I actually did the experiment and I thought I saw more colors when I changed to a grating having more lines per mm. I also thought that the spacings had become too little for some wavelengths of visible light to pass through, but I was wrong. Thanks for the answer and have a nice day.
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    Spectroscopy via diffraction gratings with different spacings

    What's the difference when I observe the emission lines of say, Hydrogen or Neon, on two diffraction gratings having different line spacings? Will there be colors that will only be observed in one and not the other? Thank you!
  6. Q

    Matter-Antimatter Pair Annihilation: Exploring the Mystery

    Thank you very much for the feedbacks! I appreciate it. =)
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    Is is possible to do graduate-level research without getting an adviser?

    The sad reality in my university is that there is no one who can advise me regarding the topics that I'm interested in, usually about theoretical physics. I live in a 3rd world country and the state of scientific research here is frustrating. Don't get me wrong, my professors are doing well with...
  8. Q

    Matter-Antimatter Pair Annihilation: Exploring the Mystery

    Why does an matter-antimatter pair annihilate each other instead of "sticking" together (i.e. like ordinary matter with opposite charges do)?
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    Intuitive Understanding for Commutation

    Let me try. :smile: Operators in quantum mechanics are also called observables. The name stems from the fact that operators represent what can be observed or measured in a system. Position, momentum and energy are the observables we are introduced to in quantum mechanics. We can measure/observe...
  10. Q

    Integration: Action Variable J

    Homework Statement A particle of mass m moves in one dimension subject to the potential V = \frac{a}{\sin^2(x/x_0)} Obtain an integral expression for Hamilton's characteristic function. Under what conditions can action-angle variables be used? Assuming these are met, find the frequency of...
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    Cosmology: a good career choice?

    I think not having a PhD is not an end-of-it-all for those who love cosmology (or for other physics fields in general). I want to talk of two groups that people who have interest can mostly belong to: The first group are those people who can be contented just to know the technical or...
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    Quantum Mechanics - Supplemental text?

    Try "Principles of Quantum Mechanics" by Shankar. =) Its approach might be different from Griffiths since it gives you the bra-ket formalism right at the start, but I find it to be the best introductory QM book around. Or try to review your differential equations / orthogonal functions (under...
  13. Q

    Jacobian and Multiple Integral

    I was self-studying the Jacobian and the change in variables when I came upon the following problem: In the integral I = \int_0^\infty \int_0^\infty \frac{x^2 + y^2}{1 + (x^2 - y^2)^2} e^{-2xy} \, dx dy , make the change of variables u = x^2 - y^2 , v = 2xy , and evaluate...
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    Becoming a Mathematical Physicist

    Thanks Tiger99 for the advice on Lie Groups and some of the other stuff. Um yeah I haven't learned about Riemannian Geometry yet, but I guess it proceeds after I learn differential geometry. As for algebraic geometry, what are the prerequisites for it? Is it the same as geometric algebra...
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    Becoming a Mathematical Physicist

    I hear all these topics like Lie Algebra, Symplectic Geometry, Hopf Algebra, Clifford Algebra, Quantum Groups, Homology, Poisson Algebra, Semi-Riemannian Geometry and the list goes on.. As of the moment, I honestly have no idea what they are. But probably these topics are related or are even...
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