Wavefunctions for Indistinguishable and Distinguishable particles -

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SUMMARY

This discussion focuses on the formulation of wavefunctions for two-particle systems in a one-dimensional potential well, specifically addressing distinguishable and indistinguishable particles. For two distinguishable spin-0 particles, the wavefunction is symmetric: (|0>|1> + |1>|0>)/sqrt(2). For two identical spin-1/2 particles, the wavefunction is antisymmetric due to the Pauli Exclusion Principle: (|0>|1> - |1>|0>)/sqrt(2). The discussion also highlights the confusion surrounding the spatial and spin components of wavefunctions and their time dependence, emphasizing the orthogonality of spin states.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly wavefunctions
  • Familiarity with the Pauli Exclusion Principle
  • Knowledge of single-particle energy eigenstates in quantum wells
  • Basic concepts of spin states and their representations
NEXT STEPS
  • Study the derivation of two-particle wavefunctions in quantum mechanics
  • Learn about the implications of the Pauli Exclusion Principle on fermionic systems
  • Explore the time evolution of wavefunctions in quantum mechanics
  • Investigate the mathematical representation of spin states using matrices
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Students preparing for quantum mechanics exams, physicists studying particle systems, and anyone interested in the behavior of indistinguishable particles in quantum wells.

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Wavefunctions for Indistinguishable and Distinguishable particles - URGENT

Homework Statement


A one-dimensional potential well has a set of single-particle energy eigenstates Un(x) with energies En=E_o n^2 where n=1,2,3... Two particles are placed in the well with three possible sets of properties.
a)2 distinguishable spin 0 particles
b)2 identical spin 0 particles
c)2 identical spin 1/2 particles

Write down the spatial part of the two-particle wave functions at t=0 for the two lowest energy states of the two-particle system, and hence give the degeneracies of these energy states and explain how these two-particle wavefunctions depend on time


Homework Equations



The Attempt at a Solution


I am getting incredibly confused by two-particle wavefunctions and between the spatial and spin states...

a) If there are 2 indenticle spin 0 particles: The wavefunction must be symmetric then would the wavefunction just be
(|0>|1> + |1>|0>)/sqrt(2)

b) 2 identicle spin 1/2 particles: The wavefunction must be antisymmetric due to Pauli Exclusion Principle so
(|0>|1> - |1> |0>)/sqrt(2)

c) 2 indistinguishable particles (boson or fermion) would it just be a wavefunction with 6 dimensions
ie phi(r1,r2)

How would you then write the spin part of the wavefunction...and how do they depend on time...

Realise this might be all wrong but I have an exam coming up and would REALLY appreciate someone clarifying this!
 
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Spin is one of those concepts that seems really hard to understand. The simple answer is that essentially all that is required is that opposite spins are orthogonal to each other in a particular basis.

So if you have spin up and spin down you might represent them as matrices like:

Spin up:\left[ \begin{array}{cc}1 \\ 0 \end{array} \right]Spin down:\left[ \begin{array}{cc}0 \\ 1 \end{array} \right]
 


Does that mean that my wavefunctions look correct?

How would they differ for the two lowest energy states?
 

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