Expectation value of P for an infinite-square well

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SUMMARY

The expectation value of momentum

for a quantum system described by an infinite-square well can be calculated directly from the initial wavefunction ψ(x,0) using the formula

= -ih∫ψ*(x,0)∂/∂x ψ(x,0)dx. There is no requirement to first determine the time-dependent wavefunction ψ(x,t) to compute

at t = 0. This approach is valid as long as the initial wavefunction is properly defined.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with wavefunctions and their properties
  • Knowledge of the infinite-square well model
  • Basic calculus, particularly integration and differentiation
NEXT STEPS
  • Study the derivation of the momentum operator in quantum mechanics
  • Learn about time evolution of wavefunctions in quantum systems
  • Explore the implications of the infinite-square well on wavefunction behavior
  • Investigate the role of expectation values in quantum mechanics
USEFUL FOR

Students and professionals in physics, particularly those focusing on quantum mechanics, wavefunction analysis, and the mathematical foundations of quantum systems.

jmm5872
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I just have a simple question to get me started. If I am given an initial value wavefunction ψ(x,0) and I am asked to find <P> at t = 0 can I use this:

<P> = -ih∫ψ*(x,0)\frac{∂}{∂x}ψ(x,0)dx

or do I need to find ψ(x,t) before I find <P>?
 
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