Bound states for a half harmonic oscillator

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SUMMARY

The discussion centers on calculating bound states for a half harmonic oscillator, defined by the potential (1/2)kx² for x>0 and infinity for x<0. Two integral formulas are proposed for determining the bound states: \int p(x) dx = (n - 1/4)h and \int p(x) dx = (n - 1/2)h. The correct approach emphasizes the necessity of matching energy eigenfunctions to those of the full harmonic oscillator, considering the boundary condition at x=0. The discussion concludes that only specific eigenfunctions of the full oscillator satisfy the conditions for the half harmonic oscillator.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly the Schrödinger equation.
  • Familiarity with harmonic oscillators and their potential energy functions.
  • Knowledge of semiclassical approximation methods in quantum mechanics.
  • Ability to interpret and manipulate wave functions and eigenfunctions.
NEXT STEPS
  • Study the time-independent Schrödinger equation for harmonic oscillators.
  • Learn about boundary conditions and their impact on wave functions in quantum systems.
  • Explore semiclassical methods and their applications in quantum mechanics.
  • Investigate the relationship between eigenfunctions of the half and full harmonic oscillators.
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Quantum mechanics students, physicists specializing in quantum theory, and researchers focusing on potential wells and bound states in quantum systems.

praharmitra
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We have a potential that is (1/2)kx^2 for x>0 and is infinity for x<0 ( half harmonic oscillator.

Now i want to calculate the bound states of the system for given E. My question is this:

Do we apply

1. \int p(x) dx = (n - \frac{1}{4} ) h ( Since there is only one turning point that can have a connection formula. This is what is given in my book

2. \int p(x) dx = (n - \frac{1}{2} ) h (This is what my teacher mentioned. I am not too sure about this.)

In both cases the integral is take over the entire classical path of the particle.
 
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I'm not sure why you're messing around with semiclassical formulae when it's easy to solve this problem exactly ... Hint: on the right, an energy eigenfunction must be the same as an energy eigenfunction for the full oscillator (because they obey the same time-independent Schrödinger equation in this region), but the wall at x=0 means that the only allowed eigenfunctions must also have the property that ____________ (fill in the blank!). Only some of the eignefunctions of the full oscillator have this property ...
 
Do what Avodyne says. But then you must also show that the set of eigenfunctions you get this way are all the eigenfunctions there are. You can do that by showing that any arbitrary eigenfunction for the half harmonic oscillator can be used to definine an eigenfunction for the full harmonic oscillator.
 

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