Stat mech: partition functions for N distinguishable harmonic oscill-

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SUMMARY

The discussion centers on calculating the canonical partition function for a system of N distinguishable, non-interacting harmonic oscillators using both Schrödinger's equation and Newton's equations of motion. The Hamiltonian is defined as H = Ʃ(p_i^2/2m) + Ʃ(1/2)k|r_i - r_i^o|^2, where r_i^o represents the equilibrium position. The energy eigenvalues for quantum harmonic oscillators are given by E_n = ℏω(1/2 + n), which is crucial for deriving the partition function in the quantum case. Participants express confusion regarding the relationship between Schrödinger's equation and the partition function, particularly in separating functions of position and momentum.

PREREQUISITES
  • Understanding of canonical partition functions in statistical mechanics
  • Familiarity with Schrödinger's equation and its implications for quantum systems
  • Knowledge of Hamiltonian mechanics and Newton's equations of motion
  • Basic concepts of energy eigenvalues in quantum harmonic oscillators
NEXT STEPS
  • Study the derivation of canonical partition functions for quantum systems
  • Explore the implications of Schrödinger's equation on particle behavior in harmonic oscillators
  • Learn about the classical limit of quantum systems and its relation to Newton's equations
  • Investigate the calculation of energy eigenvalues for various quantum systems
USEFUL FOR

Students and researchers in physics, particularly those focusing on statistical mechanics, quantum mechanics, and thermodynamics, will benefit from this discussion.

kd215
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Homework Statement


Consider a system of N distinguishable, non-interacting harmonic oscillators. The Hamiltonian is given (shown below).
Assuming that the oscillators obey Schrödinger's equation, determine the canonical partition function for the system. Then assume the oscillators obey Newton's equations of motion and determine the partition function for the system.


Homework Equations


H = Ʃ\frac{p_i^2}{2m} +Ʃ\frac{1}{2}k|r_i-r_i^o|^2

r_i^o is the equilibrium position of the ith oscillator particle

The Attempt at a Solution



So for the first question, Schrödinger's equation means that we can only exactly know the position or the momentum for a particle, right? I've been trying to factorize the partition function as two functions that are dependent on either position or momenta. So if I do this correctly, would I obtain two functions that are both partition functions? And the one that's a function of momenta would be what I am supposed to find in the second question?

I'm just now even sure if I'm interpreting this correctly. I feel like my partition function that is a function of momenta is just the Boltzmann weighted sum.

Please just let me know if I'm even thinking in the right direction.
Thanks!
 
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kd215 said:
So for the first question, Schrödinger's equation means that we can only exactly know the position or the momentum for a particle, right?

I don't understand what Schrödinger's equation has to do with that.

Do you remember that the energy eigenvalues for a quantum harmonic oscillators are E_n = \hbar \omega (\frac{1}{2}+n) ?
 

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