Recent content by christianpoved

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    Infinite square well with barrier in the middle

    Homework Statement Show that the energy levels of a double square well V_{S}(x)= \begin{cases} \infty, & \left|x\right|>b\\ 0, & a<\left|x\right|<b\\ \infty, & \left|x\right|<a \end{cases} are doubly degenerate. (Done) Now suppose that the barrier between -a and a is very high, but finite...
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    Charge distribution and potential in a 1-dimensional quasistatic syste

    Homework Statement suppose you have an 1-dimensional system with a charge distribution ##\rho(x)## (not given) moving with an speed ##v(x)##, calculate the potential ##\phi(x)## and the charge distribution ##\rho(x)## in the quasistatic limit ##\frac{d}{dt}=0##. Homework Equations...
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    1/2 spin particle in a norm-constant magnetic field

    Hahahahahaha, I will check it again after i take QM but I have to do it for some "Geometry for physicists" course that I'm taking, is sad that the math is clear but not the physics :(
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    1/2 spin particle in a norm-constant magnetic field

    Whoa... thanks, but I feel that i don't understand the solution (i haven't taken the QM course yet), why are they using the pauli matrices in the hamiltonian?
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    1/2 spin particle in a norm-constant magnetic field

    Hello everybody, I have a curious excercise, there is a 1/2 spin particle in a magnetic field ##\vec{B}(t)## with ##||\vec{B}(t)||## constant, orientated in an angle ##\theta## from the ##z## axis rotating with an angular speed ##\Omega##. The hamiltonian will be $$H(t)=-\vec{S}\cdot\vec{B}$$...
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    Why using diff. forms in electromagnetism?

    In electromagnetism we introduce the following differential form \begin{array}{c} \mathbb{F}=F_{\mu \nu}dx^{\mu}\wedge dx^{\nu} \end{array} Then the homogeneus Maxwell equations are equivalent to: \begin{array}{c} d\mathbb{F} = 0 \end{array} And is nice, but what purpose does this have...
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    Approximate the strong force between two protons.

    You know that strong force keeps the nucleus together, then the system must be in equilibrium, then the strong force must be equal to the coulomb force between the protons
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    Two object run together to the earth despite of their mass

    Hey! the answer is "no", that's not right this doesn't have anything to do with power. Everything falls with the same acceleration because this acceleration is independant of the mass, some easy calculations can be done to show it.
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    Do Physics and Engineering Majors Need Real Analysis?

    Analysis is "just" a formalization of all the topics you took in your calculus courses. In first instance analysis won't be helpful but will help you to open your mind and will be useful when you get into another mathematical topics, but perse is not helpful in engineering.
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    What are some applications of Lie derivative in physics?

    Oh yeah, I also have some questions about the exterior derivative and Maxwell equations but I'll ask this another time
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    Relation between wavefunction of the photon and the Four-potential

    Hey! Maybe this is a "piece of cake" question, but here is the thing, i have the Maxwell equations in the Lorenz gauge are \begin{array}{c} \partial_{\mu}\partial^{\mu}A^{\nu}=\mu_{0}j^{\nu} \end{array} In vacuum this gets reduced into \begin{array}{c} \partial_{\mu}\partial^{\mu}A^{\nu}=0...
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    What are some applications of Lie derivative in physics?

    Wow, thanks everybody for the examples, everything seems useful now!
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    What are some applications of Lie derivative in physics?

    Hello everybody, I am an undergrad physics student and I'm taking some "Geometry and Topology for physicist" course. We saw Lie Derivative some time ago and I still don't know how can I use it on physics, can anyone give me some examples? thanks
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    Can I have different wavenumber and frequency in E and B for a plane e

    Thanks! I ended up solving it yesterday taking the curl in 3, but taking the time derivative works as well. :)
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    Can I have different wavenumber and frequency in E and B for a plane e

    Homework Statement To solve the wave equations in vacuum for ##\vec{E}## and ##\vec{B}## we made the ansatz: \begin{array}{cc} \vec{E}\left(\vec{r},t\right)=\vec{E}_{0}\cos\left(\vec{k}\cdot\vec{r}-\omega t+\delta\right)...
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