Combination of wavefunctions in oscillator

In summary, the given equation is a combination of the first three eigenfunctions in the 1D harmonic oscillator, with \psi_0, \psi_1, and \psi_2 being normalised. To determine the value of |\gamma|, one can obtain the normalised functions for the ground state and first two excited states and expand \psi(x). The equation can then be plugged into the time dependent Schrodinger equation, with the property of normalisation being \int^{∞}_{-∞} \psi^{*}\psi dx = 1. By simplifying the result using the properties of the harmonic oscillator wave functions, the value of |\gamma| can be determined.
  • #1
cfwoods
2
0

Homework Statement


The equation [itex]\psi(x) = \frac{1}{sqrt(2)}\psi_0 (x) + \frac{i}{sqrt(5)}\psi_1 (x) + \gamma\psi_2 (x)[/itex]

is a combination of the first three eigenfunctions in the 1D harmonic oscillator. So, [itex]\psi_0 = Ae^{-mωx^2 /2\hbar}[/itex] and so on for the first and second excited states. If [itex]\psi_0[/itex], [itex]\psi_1[/itex] and [itex]\psi_2[/itex] are normalised, and [itex]\psi(x)[/itex] is also normalised, determine [itex]|\gamma|[/itex]

The Attempt at a Solution



You can obtain the normalised functions for the ground state and first two excited states from a variety of methods, and you can then expand out [itex]\psi(x)[/itex]. I tried plugging that back into the time dependent Schrodinger equation, but that didn't help (and it also gave a messy derivative) so I am at a loss as to how i can proceed.
 
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  • #2
cfwoods said:
You can obtain the normalised functions for the ground state and first two excited states from a variety of methods, and you can then expand out [itex]\psi(x)[/itex].
It is stated that ##\psi_0##, ##\psi_1##, and ##\psi_2## are taken to be normalized.

cfwoods said:
I tried plugging that back into the time dependent Schrodinger equation
How is that realted to normalization?

Let's start from the beginning: what equation does ##\psi(x)## statisfy if it is normalized?
 
  • #3
Hmm it satisfies [itex]\int^{∞}_{-∞} \psi^{*}\psi dx = 1[/itex] I think
 
  • #4
cfwoods said:
Hmm it satisfies [itex]\int^{∞}_{-∞} \psi^{*}\psi dx = 1[/itex] I think
Correct. So plug in there the ##\psi(x)## of the problem. Keep the notation ##\psi_0## and so on (i.e., do not write the explicit functions of ##x##) and use the properties of the harmonic oscillator wave functions to simplify the result.
 
  • #5


I would first clarify the goal of this exercise. Are we trying to determine the value of |\gamma| or understand the physical significance of this combination of wavefunctions?

If the goal is to determine |\gamma|, we can use the fact that \psi(x) is also normalized to set up an integral and solve for |\gamma|. Alternatively, we can use the fact that the wavefunction must be continuous and differentiable to set up a system of equations and solve for |\gamma|.

If the goal is to understand the physical significance of this combination of wavefunctions, we can look at the form of the wavefunction and see that it contains contributions from the ground state, first excited state, and second excited state. This suggests that the resulting wavefunction may exhibit characteristics of all three states, which could have implications for the system being modeled. Further analysis and exploration of this wavefunction may provide insights into the system's behavior.
 

FAQ: Combination of wavefunctions in oscillator

1. What is a combination of wavefunctions in an oscillator?

A combination of wavefunctions in an oscillator refers to the mathematical technique used to find the overall wavefunction of a system that is composed of multiple oscillators. It involves adding together the individual wavefunctions of each oscillator to obtain the total wavefunction of the system.

2. Why is it necessary to combine wavefunctions in an oscillator?

In an oscillator system, the individual oscillators are not independent of each other and their wavefunctions are interdependent. Therefore, combining the wavefunctions is necessary to accurately describe the behavior of the entire system and its energy levels.

3. How are wavefunctions combined in an oscillator?

The wavefunctions of oscillators are combined using the principle of superposition, where the individual wavefunctions are added together to obtain the total wavefunction. This is similar to how waves combine in the physical world, where the amplitudes of two waves are added together to obtain a combined wave.

4. Can the combined wavefunction in an oscillator describe the behavior of each individual oscillator?

No, the combined wavefunction in an oscillator only represents the overall behavior of the system as a whole. It cannot be used to accurately describe the behavior of each individual oscillator, as their wavefunctions are interdependent and cannot be separated.

5. What information can be obtained from the combined wavefunction in an oscillator system?

The combined wavefunction in an oscillator system can provide information about the energy levels, frequencies, and probabilities of the system. It can also be used to calculate the average position and momentum of the system, as well as the probability of finding the system in a certain state.

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