Probability density and acceleration

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SUMMARY

The discussion centers on the probability density of an object on a pendulum, particularly how energy levels affect its distribution. At low energy states, the object is more likely to be found at the bottom of the swing, while higher energy states yield a probability wave that resembles classical expectations with increased frequency. However, even at high energy, oscillations in probability density persist, raising questions about the object's motion and acceleration through space. The conversation highlights the distinction between stationary states derived from the Schrödinger equation and classical behavior, emphasizing that individual eigenstates do not align with classical intuition.

PREREQUISITES
  • Understanding of quantum mechanics concepts, particularly wavefunctions and probability density.
  • Familiarity with the Schrödinger equation and its application to harmonic oscillators.
  • Knowledge of classical mechanics, specifically pendulum motion.
  • Basic grasp of superposition principles in quantum mechanics.
NEXT STEPS
  • Study the implications of wavefunctions in quantum mechanics, focusing on stationary states.
  • Explore the concept of superposition in quantum systems, particularly with harmonic oscillators.
  • Investigate the relationship between quantum probability density and classical motion.
  • Learn about expectation values and their significance in interpreting quantum states.
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Students and professionals in physics, particularly those studying quantum mechanics, wave-particle duality, and the behavior of systems like pendulums in both classical and quantum contexts.

Jarvis323
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In class we went over the probability density for an object on a pendulum, and how at the lowest energy states, you would have strange distributions such as the object being more likely to be found at the bottom. But as you increase the energy level, the wave equation becomes more and more like how you would expect, as the frequency of the probability wave gets higher, and the sides taper up.

But even in very high states, you still have these "oscillations" in probability of the object being in a given place along the path the pendulum swings, even though the oscillations might be very closely spaced.

I was wondering if this means anything in terms of how the object moves or accelerates through space? If you can have these very high frequency oscillations of probability density along an objects trajectory, does this mean that the object is not moving "smoothly" through space? For example instead of moving continuously, at the lowest levels it's actually making incremental bursts forward, or something of that sort?
 
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What do you mean "an object on a pendulum"?
Do you mean you have been solving the Schrödinger equation for the harmonic oscillator potential?

If so, then the wavefunctions you found are for stationary states - i.e. there is an important sense that they represent something "not moving".

Individual eigenstates do not correspond to any intuition drawn from classical behavior.

The classical behavior of the particle is given by the expectation value of the wavefunction.

Work a superposition of, say, the first two, and you'll see what happens.
 

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