Recent content by cscott

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    How can we solve this temperature dependent integral in solid state physics?

    Homework Statement Trying to solve this integral \int_0^T \frac{dT'}{T'}\frac{d}{dT'}U(T',V) where the temperature dependent part of U is \Sigma \frac{h\omega}{\exp(\beta\omega)-1} The Attempt at a Solution using x = hw/T I find that I need to integrate \frac{x^3...
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    Finding the Potential Between Two Coaxial Cylinders Using Laplace's Equation

    I made a typo in my boundary conditions Boundary conditions (in volts): V(a,\phi) = 2 \cos \phi V(b,\phi) = 12 \sin \phiTaking V(r,\phi)_{k=1} gives, V(r,\phi) = r(a_1 \cos \phi + b_1 \sin \phi)+\frac{1}{r}(c_1\cos \phi + d_1 \sin \phi) I will take a look at this...
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    Finding the Potential Between Two Coaxial Cylinders Using Laplace's Equation

    Homework Statement Two coaxial cylinders, radii {a,b} where b>a. Find the potential between the two cylinder surfaces. Boundary conditions: V(a,\phi) = 2 \cos \phi V(b,\phi) = 12 \sin \phiHomework Equations Solution by separation of variables: V(r,\phi) = a_0 + b_0 \ln s + \sum_k \left[...
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    Z for classical particles in B-field

    So because U has nothing to do with the magnetic field, I need to eliminate the vector potential from, \Pi_n \int \exp \left [-\frac{\beta}{2m_n} (\vec{p}_n - q \vec{A})^2 \right] d^3 p_n and change variable, \vec{u}_n = \vec{p_n}-q\vec{A} thus eliminating vector potential? Are the end...
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    Z for classical particles in B-field

    Homework Statement Show that the free energy of classical particles with no internal magnetic moment is always independent of magnetic field. Hint: Write down Z for N classical particles. Let the particles interact by U which depends only on the positions of the interacting particles. Show...
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    What Forces Act on a Dipole Near an Infinite Metal Plane?

    Homework Statement Point electric dipole \vec{p}=p_0 \hat{z} is a distance d above an infinite metal plane of surface normal \hat{n}=\hat{z}. What is the force on the dipole. Is the dipole attracted to, or repelled from the surface?Homework Equations V(r) = \frac{\hat{n} \cdot \hat{p}}{4 \pi...
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    DoS in anisotropic conduction band

    Homework Statement have band dispersion \epsilon = \epsilon_c + \frac{h^2 k_x^2}{2 m_x} + \frac{h^2 k_y^2}{2 m_y} + \frac{h^2 k_z^2}{2 m_z} Show density of states is g(\epsilon) = \frac{m^{3/2}}{\pi^2 h^2} \sqrt{2|\epsilon - \epsilon_c|} Homework Equations 2 \frac{d\vec{k}}{(2\pi)^3} =...
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    Spin-1 particle in uniaxial crystal field

    Thanks! I definitely thought about that too hard haha
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    Spin-1 particle in uniaxial crystal field

    Homework Statement H = -D(S^z)^2 for cases D>0, D<0, where D<0 should remove the degeneracy in the ground state.Homework Equations H = -D(S^z)^2 = -D\hbar^2 (1 0 0; 0 0 0; 0 0 1) (`;' separates rows) det(H-1E)= 0, or by inspection... The Attempt at a Solution I get, for D>0, E_1 = -D...
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    |1s> -> |2p> transition probabilities

    Homework Statement A hydrogen atom is placed in a time-dependent homogeneous electric field given by \epsilon = \epsilon_0 (t^2 + \tau^2)^{-1} where \epsilon_0,\tau are constants. If the atom is in the ground state at t=-\inf, obtain the probability that it ill be found in a 2p state at...
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    Time-averaged potential of hydrogen

    Homework Statement The time-averaged potential of a neutral hydrogen atom is given by V = \frac{q}{4 \pi \epsilon_0} \frac{e^{-\alpha r}}{r} \left ( 1 + \frac{\alpha r}{2} \right ) [tex]\alpha = 2/a_0[/itex], where a_0 is the Bohr radius. Find the charge distribution (continuous and...
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    Energy per particle of polarized electron gas

    Homework Statement Calculate the total internal energy per electron at zero temperature of a free noninteracting gas of electrons of density n, in the following two cases. a) First assume that states with both spin directions are populated equally. b) Now assume that the gas is fully...
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    3rd-order Energy Correction Derivation

    One last bump... haven't gotten anywhere with this.
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    How Do You Compute the 1st Order Wave Function Correction in Quantum Mechanics?

    This was the thinking I was missing! So for H' = constant there is no first-order correction because l \ne n, yes?
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