Quantum Physics [Phys 401]                                                 Spring 2005
Fourth Readings and Problems.

Reading:  

For Wednesday, February 23, read Chapter 6 in Shankar.
For Thursday, February 24, read Sections 7.1-7.3 in Shankar.
For Monday, February 28, finish reading Chapter 7 in Shankar.
For Thursday, March 3, read Chapter 8 in Shankar.
For Monday, March 14, read Chapter 9 and Sections 10.1-10.2 in Shankar.

Homework Problems:

[61] Is the operator Hermitian?
[62] Assuming that is a real constant, it the operator Hermitian?
[63] Calculate the following commutators:  (i) , (ii) , (iii)
[64] An infinite square potential well has sides at x=0 and x=2a.  The potential within the well is V=0.  At a certain moment in time, the spatial wavefunction of a particle is given by:  , for x values between 0 and a, and by for x values between a and 2a.  Obviously, a is a real positive distance here.  The spatial wavefunction vanishes everywhere outside of the well.

Determine the probability of finding this particle to have the ground state (lowest) energy at this time.

[65] Exercise 7.3.7, p.202, Shankar.
[66] Exercise 7.4.1, p. 212, Shankar.
[67] Exercise 7.4.2, p. 212, Shankar.
[68] Exercise 7.4.3, p. 212, Shankar.
[69] Exercise 7.4.4, p. 212, Shankar.
[70] A particle is in a state described by the momentum space wavefunction , where A and â are constants.  Determine whether or not this state is an eigenstate of the position operator.

[71] A particle of energy E=(4V0/3) and mass m is incident upon a potential step from the left.  The potential step occurs at x=0, and at this point, the potential steps down from its value of V=V0 on the left-hand side of the step to its value of V=0 on the right-hand side of the step.

If the spatial wavefunction on the left-hand side of the step is given by the expression , write an expression for k in terms of the parameters m, V0, and hbar.

Write the form of the wavefunction on the right side of the step, , making sure to identify any constants you might use to write it.

Determine the reflection coefficient, R, and the transmission coefficient, T, for the particle when incident upon the step from the left.

[72] Do the multiple choice question attached.

[73] Exercise 7.4.5, p. 212, Shankar.
[74] Exercise 7.4.7, p. 212, Shankar.
[75] Exercise 7.4.8, p. 213, Shankar.
[76] Exercise 7.5.2, p. 218, Shankar.
[77] Exercise 9.4.1, p. 244, Shankar.
[78] Exercise 9.4.2, p. 244, Shankar.
[79] Exercise 9.4.3, p. 244, Shankar.
[80] Exercise 9.4.4, p. 244, Shankar.