Maximizing Gibbs Entropy in Canonical Ensemble

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SUMMARY

The discussion focuses on maximizing Gibbs entropy within the canonical ensemble using Lagrange Multipliers. The user seeks clarification on the derivatives of the function concerning probabilities P(i) and the summations of ln(P(i)) and E(i). It is established that when differentiating a function of N variables, only one term survives the derivative, simplifying the process of finding the maximum entropy configuration.

PREREQUISITES
  • Understanding of Gibbs entropy and canonical ensemble concepts
  • Familiarity with Lagrange Multipliers for optimization
  • Knowledge of derivatives in multivariable calculus
  • Basic principles of statistical mechanics
NEXT STEPS
  • Study the application of Lagrange Multipliers in statistical mechanics
  • Explore the derivation of Gibbs entropy in detail
  • Learn about the implications of maximizing entropy in thermodynamic systems
  • Investigate the relationship between probabilities and energy states in canonical ensembles
USEFUL FOR

This discussion is beneficial for physicists, statisticians, and students studying thermodynamics and statistical mechanics, particularly those interested in entropy maximization techniques.

Sekonda
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Hey,

Here is the problem:

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The method by which we solve is by Langrange Multipliers, and so I believe I found the derivative of f with respects to P(i) but I have two quantities I'm sure what they equal:

Summations over i=1 to N : Ʃln(P(i)) and ƩE(i)

Thanks for any help,
S
 
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Sekonda said:
The method by which we solve is by Langrange Multipliers, and so I believe I found the derivative of f with respects to P(i) but I have two quantities I'm sure what they equal:

Summations over i=1 to N : Ʃln(P(i)) and ƩE(i)

Thanks for any help,
S

Remember you have N different quantities Pi that you are derivating with respect to. So for example if you have f(x,y) = x ln x + y ln y, then ∂f/∂x = ln x + 1 and likewise for y. There are no mixed terms, and even with a function of N variables, only one term survives the derivative.
 

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