Recent content by baouba

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    I How do i find the eigenvalues of this tough Hamiltonian?

    I have this Hamiltonian --> (http://imgur.com/a/lpxCz) Where each G is a matrix. I want to find the eigenvalues but I'm getting hung up on the fact that there are 6 indices. Each G matrix lives in a different space so I can't just multiply the G matrices together. If I built this Hamiltonain...
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    How do I find the energies of these states?

    Homework Statement Here is the problem: http://imgur.com/XEqE4SY Homework Equations |psi_s_ms> = |s, ms> ⊗ Σ D_i_j |psi_i, psi_j>[/B]The Attempt at a Solution I know the singlet state in the |s, ms> basis is |0,0> = (1/sqrt(2))[ |up, down> - |down, up>] and that the hamiltonian for this...
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    Find probability of spin state after certain time.

    Homework Statement Question: http://imgur.com/YzexPKl (only part c) Homework Equations From part a) I got |psi> = (1/sqrt(2))(e^(iwt/2)|z-up> + ie^(-iwt/2)|z-down> I expanded this wave function in the x-spin basis and got, |psi> = (1/(2))[(e^(iwt/2)+ie^(-iwt/2))|x-up> +...
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    What's the difference between these two equations?

    say we have some wavefunction |psi> and we want to find the probability of this wavefunction being in the state |q>. I get that the probability is given by P = |<q|psi>|^2 since we're projecting the wavefunction onto the basis state |q> then squaring it to give the probability density. However...
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    Do ladder operators give integer multiples of ћ?

    "Any number such that a given matrix minus that number times the identity matrix has a zero determinant." I don't see how this answers the question. should non-integer multiples of ћ be omitted or not?
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    Do ladder operators give integer multiples of ћ?

    Say I apply a raising operator to the spin state |2,-1>, then by using the the equation S+|s,ms> = ћ*sqrt(s(s+1) - ms(ms+1))|s,ms+1> I get, S+|2,-1> = sqrt(6)ћ|2,0> Does this correspond to a physical eigenvalue or should I disregard it and only take states with integer multiples of ћ as...
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    How is this equation for <x|P|x'> derived?

    but the 3rd line has <x'|x> not <x|x'>. Am I missing something?
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    How is this equation for <x|P|x'> derived?

    Thanks for replying. The 2nd line to the 3rd line is where I get lost.
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    How is this equation for <x|P|x'> derived?

    Thanks for the reply! but the whole reason we need to figure out < x | Px | x' > in the first place is because the identity operator is inserted. What's the point? Also how to do you do this derivation step by step? I'm very confused I think my prof. is skipping steps : http://imgur.com/tl07k5g
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    How is this equation for <x|P|x'> derived?

    Image: http://imgur.com/pynKr8q How is the boxed equation arrived at when looking at the step before? I think I need clarification on a few key ideas: in words, does < x | p | ψ > mean, "The momentum operator acting on the state vector, then projected onto the position basis"? If so, wouldn't...
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    Exponentials or trig functions for finite square well?

    How do you know when to use exponentials and trig functions when solving for the wave function in a finite square well? I know you can do both, but is there some way to tell before hand which method will make the problem easier? Does it have something to do with parity?
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    How do I plot this probability density over time?

    How can you tell if a given wave function isn't an eigenstate of the hamiltonian? I just don't get how if |Ψn(x, y)|^2 = |Anψn(x)e^-iEnt/h-bar|^22 and Ψ is a pure state, how doesn't the exponential factor cancel out in 1 = ∫ |Ψn(x, y)|2 dx ?
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    How do I plot this probability density over time?

    Here's the question: http://imgur.com/N60qRmw I normalized the wave function and got A = sqrt(315/8L^9) but how would I plot representative snapshots if the exponential factor will cancel when I square it? It's not a mixed state so it shouldn't depend on time as far as I can tell. Should I use...
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    How do I solve these coupled Differential Equation?

    Homework Statement dNa/dt = -Na/Ta where Na is the function and Ta is the constant dNb/dt = Na/Ta - Nb/Tb where Nb is the function and Tb is the constant Homework Equations My Prof said Nb(t) has the form Nb(t) = Cexp(-t/Ta) + Dexp(-t/Tb) The Attempt at a Solution I know the first equation...
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    Repeating Second Year: A Second Chance to Master the Basics of Physics

    This is the part I'm most frustrated about. I only really started working my ass off near the end so I could pass. I'm pretty much up to speed with what I need to know (and in some cases ahead of other students) only through self studying. I know what I should know for a 3rd year physics...
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