What distinguishes the average and most likely position of a particle?

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SUMMARY

The discussion clarifies the distinction between the average position and the most likely position of a particle, particularly in the context of probability distributions. The average position is calculated using the integral <x> = ∫0 x P(x) dx, while the most likely position is determined by locating the maximum of the probability density function P(x). The participants also explored the specific probability density function P(x) = B^2 x e^{-βx}, emphasizing the importance of correctly identifying the wave function and its modulus square in quantum mechanics.

PREREQUISITES
  • Understanding of probability distributions in quantum mechanics
  • Familiarity with wave functions and their modulus square
  • Knowledge of integration techniques, particularly integration by parts
  • Basic concepts of statistical mechanics, including average and most probable values
NEXT STEPS
  • Study the derivation of the average position using <x> = ∫0 x P(x) dx in quantum mechanics
  • Learn about the significance of the most probable position in probability distributions
  • Explore the properties of the exponential function in relation to probability density functions
  • Investigate the error function and its applications in integrals involving Gaussian distributions
USEFUL FOR

Students and professionals in physics, particularly those focused on quantum mechanics, statistical mechanics, and mathematical physics. This discussion is beneficial for anyone seeking to understand the nuances between average and most likely positions of particles in probabilistic contexts.

  • #91


OKay, well I have:

B^2\left[ -\frac{1}{2\beta}e^{-2\beta x} + frac{3}{2 \beta\left[ -frac{-x^2}{2\beta}e^{-2 \beta x} + \frac{1}{\beta} \left[ \frac{x}{2\beta}e^{-2\beta x} + 1\frac{1}{2\beta} \left[ -\frac{1}{2\beta} e^{-2\beta x} \right]\right] /right]} \right]

Which I have reduced to:

B^2\left[-\frac{x^3}{2\beta}e^{-2\beta x} + \frac(-\frac{3x^2}{4\beta^2}e^{-2\beta x} + \frac{3x}{4\beta^3}e^{-2\beta x} - \frac{3}{8\beta^4}e^{-2 \beta x} \right]

B^2 = 4\beta^2

\left[-\frac{B^2x^3}{2\beta}e^{-2\beta x} - \frac{B^23x^2}{4\beta^2}e^{-2\beta x} + \frac{B^23x}{4\beta^3}e^{-2\beta x} - \frac{3B^2}{8\beta^4}e^{-2 \beta x} \right]

\left[-\frac{4\beta x^3}{2}e^{-2\beta x} - 3x^2e^{-2\beta x} + \frac{3x}{4\beta}e^{-2\beta x} - \frac{3}{2\beta^2}e^{-2 \beta x} \right]
 
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