Recent content by jmm5872
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J
Transition Probability of Hydrogen atom in an electric field
A hydrogen atom is in its ground state and is subject to an external electric field of E = ε(\hat{x}+\hat{y}+2\hat{z})e-t/\tau I'm confused as to how to compute the matrix elements of the perturbed hamiltonian since this is not in the z direction. Would I have to do something like this...- jmm5872
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- Atom Electric Electric field Field Hydrogen Hydrogen atom Probability Transition
- Replies: 3
- Forum: Advanced Physics Homework Help
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Fourier transform from k-space to x
I have calculated a k-space function to be f(k) = \frac{1}{2k} I want to Fourier transform this to find f(x), I have found many different Fourier transform equations...can I use this one? f(x) = \frac{1}{\sqrt{2π}}\int\frac{1}{2k}e-ikxdk Limits fo integration -Infinity to Infinity...- jmm5872
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- Fourier Fourier transform Transform
- Replies: 1
- Forum: Advanced Physics Homework Help
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Entropy of molten lead freezing
Sorry, I just realized I need to take the Latent heat of melting and make it negative for freezing...this solves my first problem.- jmm5872
- Post #2
- Forum: Introductory Physics Homework Help
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Entropy of molten lead freezing
Entropy of molten lead "freezing" Lead melts at 327.5 C.° The latent heat of melting of lead is 24.1 J/g, and the heat capacity of solid lead is 0.14 J/g °C. You take 100 grams of molten lead at a temperature of 327.5 C° and pour it on the sidewalk. The lead freezes and then comes into thermal...- jmm5872
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- Entropy Freezing Lead
- Replies: 2
- Forum: Introductory Physics Homework Help
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Two particles in QHO potential and probability of distance
Two particles with equal mass m are confined by a harmonic oscillator potential of frequency ω. Assume that we somehow know that there is one particle in the first excited state and one in the second excited state. What is the probability of finding both particles within a certain distance if...- jmm5872
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- Particles Potential Probability
- Replies: 1
- Forum: Advanced Physics Homework Help
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Graduate I'm having trouble with an integral for my QM senior thesis
I figured out the problem, and it was a little bitter-sweet. The above integral was to get a c3(t) coefficient. I already solved for the c1(t) and c2(t) previously, and they all contained the same A and B unknowns. I also had the initial condition of c1(0)=0, so I was able to solve for A in... -
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Graduate I'm having trouble with an integral for my QM senior thesis
Thank you for rewriting my integral Simon! What you have written is correct, except for the upper limit of the integrand is actually e^-Ht. As for a closed form solution, I am not quite sure. The original paper I am trying to work off does a more complicated problem in which H and k are not... -
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Graduate I'm having trouble with an integral for my QM senior thesis
I have been working through a method of solving the Time-Dependent Schrödinger Equation. I'm trying to learn this techniques before I actually jump into my project, however, I have come to an integral that I have been trying to do but can't think of a way to approach it. Mathematica could not... -
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Description of a wave packet incident on a square potential barrier
A wave packet of mean energy E0 is incident on a potential square barrier. The figure below shows stills from a film showing 9 successive stages in interaction. a) True or false? The incident packet at time t = 0 describes many particles, each in a different momentum state. If false, tell...- jmm5872
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- Potential Square Wave Wave packet
- Replies: 1
- Forum: Advanced Physics Homework Help
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J
Expectation value of P for an infinite-square well
I just have a simple question to get me started. If I am given an initial value wavefunction ψ(x,0) and I am asked to find <P> at t = 0 can I use this: <P> = -ih∫ψ*(x,0)\frac{∂}{∂x}ψ(x,0)dx or do I need to find ψ(x,t) before I find <P>?- jmm5872
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- Expectation Expectation value Value
- Replies: 1
- Forum: Advanced Physics Homework Help
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Transmission Coefficient of a double delta function potential
V(x) = |g| (δ(x+L)+δ(x-L) Consider scattering from a repulsive twin-delta function potential. Calculate R and T. I'm mostly confused about computing the T coefficients for multiple barriers. Would I compute the T coefficient for the barrier at x = -L and at x = L separately? Then...- jmm5872
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- Coefficient Delta Delta function Delta function potential Function Potential Transmission Transmission coefficient
- Replies: 1
- Forum: Advanced Physics Homework Help
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Motion of a mass m confined to the x-axis (Hamiltonian)
Ah, okay, I understand now. I forgot that the potential is opposite the sign of force! Thank you! F = -dU/dx- jmm5872
- Post #5
- Forum: Advanced Physics Homework Help
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Motion of a mass m confined to the x-axis (Hamiltonian)
The problem specifically states that k > 0, and F = kx, which gives U = 1/2 kx^2. I don't really understand what you are trying to say, or where the F = -kx that you wrote comes from.- jmm5872
- Post #3
- Forum: Advanced Physics Homework Help
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Motion of a mass m confined to the x-axis (Hamiltonian)
Consider a mass m confined to the x-axis and subject to a force Fx=kx where k>0. Write down and sketch the potential energy U(x) and describe the possible motions of the mass. (Distinguish between the cases that E>0 and E<0. It is the part in parenthesis that confuses me. I can't...- jmm5872
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- Hamiltonian Mass Motion
- Replies: 4
- Forum: Advanced Physics Homework Help
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Complex Analysis, Line Integrals and Cauchy Conceptually
I am just trying to get the conceptual basics in my head. Can I think of things this way... If you are taking the integral of a function f(z) along a curve γ in a region A. If the curve is closed and f(z) is analytic on the entire curve as well as everywhere inside the curve, then the...- jmm5872
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- Analysis Cauchy Complex Complex analysis Integrals Line Line integrals
- Replies: 1
- Forum: Calculus and Beyond Homework Help