Questions
Question 1
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Write the potential energy of a one-dimensional harmonic oscillator in terms of \(m\), \(\omega\), and \(x\).
Question 2
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Write the allowed energy levels of the quantum harmonic oscillator.
Question 3
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What is the ground-state energy of a quantum harmonic oscillator?
Question 4
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Find the energy spacing \(E_{n+1}-E_n\).
Question 5
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A harmonic oscillator has adjacent energy spacing \(0.20\,\mathrm{eV}\). Find \(\omega\) in terms of this spacing.
Question 6
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What photon energy is emitted in a transition from \(n=5\) to \(n=2\) for a harmonic oscillator?
Question 7
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Write the ground-state length scale \(x_0\) for a quantum harmonic oscillator.
Question 8
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How does the ground-state width change if \(\omega\) is quadrupled while \(m\) is fixed?
Question 9
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Find the classical turning-point magnitude for an oscillator state of energy \(E_n\).
Question 10
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How many nodes does the \(n=4\) harmonic oscillator eigenstate have?
Question 11
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State the parity pattern of one-dimensional harmonic oscillator eigenstates.
Question 12
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Find \(\langle x\rangle\) for any harmonic oscillator energy eigenstate centered at \(x=0\).
Question 13
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For the oscillator ground state, use \(\Delta x=\sqrt{\hbar/(2m\omega)}\) and \(\Delta p=\sqrt{\hbar m\omega/2}\) to find \(\Delta x\Delta p\).
Question 14
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Using the virial theorem for a harmonic oscillator, find \(\langle K\rangle\) and \(\langle V\rangle\) in the state \(n\).
Question 15
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Find \(\langle x^2\rangle\) for the oscillator ground state using the virial theorem.
Question 16
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Why is the oscillator ground-state energy nonzero?
Question 17
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Contrast the energy spacing of a harmonic oscillator with that of a particle in a box.
Question 18
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A perturbation can only cause transitions with \(\Delta n=\pm1\) when it is proportional to \(x\). Explain this selection rule qualitatively using parity.
Question 19
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Use the ladder-operator result \(\hat H=\hbar\omega(\hat a^\dagger\hat a+1/2)\) to justify the oscillator spectrum.
Question 20
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Estimate the oscillator zero-point energy by minimizing \(E\approx (\Delta p)^2/(2m)+m\omega^2(\Delta x)^2/2\) with \(\Delta p\approx\hbar/(2\Delta x)\).