Introduction To Quantum Mechanics
3rd Edition
ISBN: 9781107189638
Author: Griffiths, David J., Schroeter, Darrell F.
Publisher: Cambridge University Press
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Chapter 9, Problem 9.17P
(a)
To determine
The WKB wave function in regions (i)
(b)
To determine
Show that
(c)
To determine
Show that the quantization condition becomes
(d)
To determine
Sketch the given potential and find
(e)
To determine
Show that particle starts out in the right well oscillates back and forth between the wells, with a period
(f)
To determine
The expression for
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4. (Kittel 7.4) Chemical potential versus temperature. Explain graphically why the
initial curvature of u versus 7 is upward for a fermion gas in one dimension and
downward in three dimensions (Figure 7.7).
Hint: The D₁(e) and D, (e) curves are different, where D, is given in Problem 1. It
will be found useful to set up the integral for N, the number of particles, and to
consider from the graphs the behavior of the integrand between zero temperature and
a finite temperature.
Problem 1: Two-level system. Canonical ensemble.
Consider N impurity atoms trapped in a solid matrix.
Each impurity can be in one of two states, with energies 0 and ɛ, respectively.
The energy level are non-degenerate.
1) Compute the partition function Z, for one subsystem (i.e. one impurity atom).
2) Compute the partition function Z for the system.
3) Deduce the free energy.
4) Deduce the entropy.
5) Deduce the internal energy.
Problem 2: Two-level system. Canonical ensemble.
Redo the above problem. We assume that the ground level is non degenerate
and the excited level is g-fold degenerate.
8.5 Calculate the grand partition function for a system of N noninteracting quantum
mechanical harmonic oscillators, all of which have the same natural frequency wn. Do this
for the following two cases:
(a) Boltzmann statistics
(b) Bose statistics.
Chapter 9 Solutions
Introduction To Quantum Mechanics
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