What Are the Key Questions About Quantum Mechanics Fundamentals?

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Key questions about quantum mechanics fundamentals include the difference between the ordinary wave equation and the Schrödinger equation, specifically why the latter connects first-order time derivatives with second-order space derivatives. The discussion raises the issue of the wavefunction's dimension, suggesting it should be L-3/2, yet questioning why it cannot be directly measured. Additionally, it explores the continuity of the wavefunction and its derivatives, positing that if the wavefunction is continuous, then its first derivative should also be continuous. The conversation emphasizes the complexities of measurement in quantum mechanics, which complicate the ability to measure the wavefunction directly. Understanding these foundational concepts is crucial for grasping the principles of quantum mechanics.
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Homework Statement



I've some doubts in the basic quantum mechanics.I know these are too simple. But can't figure out the exact answer.


1. Ordinary wave equation relates second order time derivative to second order space derivative.But Schrodinger equation connects first order time derivative with second order space derivative.Why this difference?

2. I've seen in a book that wavefunction should have a dimension of L-3/2(because |ψ|2dx should be dimensionless).Then why can't we measure wavefunction?

3.From Schrodinger equation, ψ should be continuous.But how can we say that ∂ψ/∂x should be continuous also?


The Attempt at a Solution



1. A book says this is to make wave function independant of the properties of the particle(if wave function for free particle is considered).But i can't understand it properly.

3.I think (may be wrong) when ψ is a continuous function of x, ∂ψ/∂t should be a continuos function of x. ie, LHS of Sch. equation is continous. Then RHS also need to be continuous. But it don't imply that ∂ψ/∂x should be continuous.
 
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In regards to 2, think about what happens when you measure something in quantum mechanics, how would this make it hard for you to measure the wavefunction?
 
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