Gibbs entropy
Microstate probabilities quantify statistical entropy.
Key knowledge
For normalized discrete microstate probabilities, Gibbs entropy is S = −k_BΣ_i p_i ln p_i, using natural logarithms and the convention 0 ln 0 = 0.
Values and equations
S = −k_BΣ_i p_i ln p_i
- S
- Statistical entropy J K⁻¹
- k_B
- Boltzmann constant J K⁻¹
- p_i
- Normalized microstate probability
Conditions and scope
- p_i ≥ 0, Σ_i p_i = 1; the sum must converge for finite entropy.
- Continuous distributions require a defined measure; raw differential entropy cannot be substituted without qualification.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Lecture 3, equation 22: general Gibbs entropy and microstate probabilities.
2026-10-10 · Discrete Gibbs definition only; arbitrary information entropy is not automatically a thermodynamic state function.
Entry details
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- physics-gibbs-entropy
- Revision
- university-reference.1
- Structured reference record
- University reference · University core expansion