Seonglae ChoSemantic entropy: Calculates entropy over "meaning clusters" rather than "token probabilities". Strong for hallucination detection
Semantic uncertainty, ICLR 2023 Lorenz
In natural language generation (NLG), measuring uncertainty properly requires looking beyond simple token-level probabilities to semantic-level uncertainty
Semantic Entropy Nature 2024
This is quantified by the metric semantic entropy
Token frequency neurons
Analysis shows that specific neurons exist within LLMs that have an uncertainty regulation mechanism: Pulls or pushes the output distribution toward the token frequency (unigram) distribution, making it regress to the base distribution when uncertain.
semantic-entropy-probesOATML • Updated 2026 Feb 10 20:17
semantic-entropy-probes
OATML • Updated 2026 Feb 10 20:17
