von Neumann entropy

/vɔn ˈnoɪ.mən ˈɛn.tɹə.pi/

noun

The entropy of a quantum state. If the state is expressed as a quantum density matrix ρ, then this entropy can be expressed mathematically as S=-tr(ρ log ρ) where tr is the trace operator and the logarithm is natural.

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Meanings

noun
  1. quantum mechanicsThe entropy of a quantum state. If the state is expressed as a quantum density matrix ρ, then this entropy can be expressed mathematically as S=-tr(ρ log ρ) where tr is the trace operator and the logarithm is natural.

Origin

Named after John von Neumann.

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Cite this entry
APA

von Neumann entropy. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/von%20Neumann%20entropy

MLA

“von Neumann entropy.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/von%20Neumann%20entropy. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “von Neumann entropy,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/von%20Neumann%20entropy.

Source: von Neumann entropy on Wiktionary, CC BY-SA 4.0.