Number of Particles in Left Half of a Confined Box with Varying Energies

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SUMMARY

The discussion centers on calculating the number of particles in the left half of a one-dimensional box containing 1000 neutral spinless particles, with 100 particles at energy 4ε0 and 900 at energy 225ε0. The participants conclude that the measurement of particles in the left half is probabilistic due to the lack of a definite number state for the left side of the box. The expectation value for a single particle at both energy levels is L/2, but this does not provide a definitive answer for the total count in the left half. The problem is identified as misguided, emphasizing the probabilistic nature of quantum measurements.

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  • Understanding of quantum mechanics, specifically particle confinement in potential boxes.
  • Familiarity with energy quantization and wave functions in quantum systems.
  • Knowledge of expectation values and their implications in probabilistic measurements.
  • Basic principles of statistical mechanics as they apply to particle distributions.
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  • Explore the derivation and application of expectation values in quantum systems.
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Students and researchers in quantum mechanics, particularly those dealing with statistical mechanics and particle behavior in confined spaces. This discussion is beneficial for anyone looking to deepen their understanding of quantum measurement and probabilistic outcomes in physics.

phoenix95
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Homework Statement


1000 neutral spinless particles are confined in a one-dimensional box of length 100 nm. At a given instant of time, if 100 of these particles have energy 4ε0 and the remaining 900 have energy 225ε0, then the number of particles in the left half of the box will be approximately

(a) 441

(b) 100

(c) 500

(d) 625

Homework Equations

The Attempt at a Solution


Energies 4ε0 and 225ε0 correspond to E2 and E15 respectively, so I tried finding the expectation value for a single particle at these energy levels which turns out to be L/2 for both. But then I thought it is irrelevant for the problem, because I can't assign a single wave function to each of the particle and carry out the calculations.
Can anyone please help me?

Thanks
 
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I think this is a misguided problem. The left side of the box is not in a particular number state, which means if you measure the number of particles of the left half of the box, the result would be probabilistic.
 
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Xu Shuang said:
I think this is a misguided problem. The left side of the box is not in a particular number state, which means if you measure the number of particles of the left half of the box, the result would be probabilistic.
In that case, how should I start?:smile:
 

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