Classification of schrodinger equation?

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Discussion Overview

The discussion revolves around the classification of the Schrödinger equation, particularly its comparison to the wave equation and the heat equation. Participants explore the implications of its first-order time dependence and the resulting behavior of quantum mechanical wave packets.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that the Schrödinger equation is often compared to the wave equation despite its similarity to the heat equation, raising questions about this classification.
  • One participant argues that the presence of the imaginary unit (i) in the Schrödinger equation leads to traveling waves, contrasting it with the heat equation.
  • Another participant points out that the first-order nature of the Schrödinger equation results in the spreading of quantum mechanical wave packets over time.
  • Questions are raised regarding the necessity of the Schrödinger equation being first order in time and its implications for experimental observations of wave packet spreading.
  • It is mentioned that all quantum mechanics texts indicate the first-order time dependence is essential for preserving the norm of the wave function, although the spread may be difficult to observe experimentally.
  • One participant compares the spread of wave packets in quantum mechanics to the spread described by the diffusion equation, which is also first order in time.

Areas of Agreement / Disagreement

Participants express differing views on the classification of the Schrödinger equation and its implications. There is no consensus on the necessity of its first-order time dependence or the visibility of wave packet spreading in experiments.

Contextual Notes

Participants highlight the complexity of the relationship between the Schrödinger equation, wave equations, and heat equations, with unresolved questions regarding definitions and experimental validation of wave packet behavior.

Who May Find This Useful

This discussion may be useful for students and educators in quantum mechanics, researchers interested in the mathematical foundations of quantum theory, and those exploring the conceptual underpinnings of wave-particle duality.

boderam
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the Schrödinger equation is sometimes called a wave equation and in my quantum mechanics text's they often show the wave equation comparing it to the Schrödinger equation. i don't understand why they do this when it is of the same form as the heat equation, it's not second order in time like the wave equation. why is this? thanks in advance.
 
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Because of the i, the Schrödinger equation does lead to traveling waves.
The exp(-t/tau) of the heat equation becomes exp(-iEt).
Because it is first order in time, a QM wave packet spreads with time.
A wave packet for the wave equation doesn't spread unless the medium is dispersive.
 
Because it is first order in time, a QM wave packet spreads with time.
why so?
 
why is it necessary that the Schrödinger equation be first order in time? or rather, why is it necessary for the wave packet to spread in time in terms of experimental results?
 
Last edited:
All QM texts show that the SE must be first order in time to preserve the norm of the the function. The spread is hard to see experimentally.
The spread is the usual spread of the diffusion equation, which is also first order in time.
 

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