Expectation Value of Position for Even Wavefunction

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Homework Help Overview

The discussion revolves around calculating the expectation values for position and momentum for a normalized wavefunction that is even, specifically characterized by the relation ψ0(-x)=ψ0(x)=ψ*0(x). A second wavefunction, ψ1, is introduced as the derivative of the first, which is noted to be odd.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to assert that the expectation value for position is zero due to the even nature of the wavefunctions, while expressing uncertainty about the momentum calculation. Some participants question the implications of symmetry properties on the expectation values.

Discussion Status

Participants are exploring the mathematical implications of symmetry in wavefunctions and discussing how these properties affect the expectation values. There is an acknowledgment of the need to clarify the relationship between the wavefunctions and their derivatives, particularly regarding their even and odd characteristics.

Contextual Notes

There is a correction regarding the nature of ψ1, which is identified as an odd function, and a suggestion to express expectation values in terms of the wavefunctions while considering their symmetry properties.

hellsteiger
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Homework Statement



Hello, I need to calculate the expectation value for position and momentum for a wavefunction that fulfills the following relation:

ψ0(-x)=ψ0(x)=ψ*0(x)

The wave function is normalised.


Homework Equations



There is also a second wave equation that is orthogonal to the first:

ψ1=Nd0/dx

I also need to calculate <x> and <p> for this wavefunction, also normalised.


The Attempt at a Solution



I am tempted to go ahead and say that the expectation value for position for both wavefunctions is 0, as they are both even. As for momentum I am not certain as to how i should proceed, inserting the relevant operator just seems to indicate to me momentum will be zero.
 
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Correction:

ψ1=Ndψ0/dx
 
I should point out that ψ1 is actually an odd function, being the derivative of an even function, it is not even as i stated earlier.
 
Just write down the expectation values of position and momentum in terms of the wave function (the position representation of the quantum state). Then discuss the mathematics given the symmetry properties, i.e., either even or odd, of the wave functions.
 

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