trureturing — Discovering truth

bibkey: wootters1998formationfunction authors: William K. Wootters year: 1998 title: “Entanglement of Formation of an Arbitrary State of Two Qubits” doi: 10.1103/PhysRevLett.80.2245 url: https://arxiv.org/abs/quant-ph/9709029v2 claim: “Equations (6)–(8) express two-qubit formation using an increasing convex binary-entropy function of concurrence.” strata_touched:

• D5/S3/Quantum/Entanglement/GraphDensity/FormationBounds license: citation-only triage: anchor

Verified locator

DOI: https://doi.org/10.1103/PhysRevLett.80.2245

Source: https://arxiv.org/abs/quant-ph/9709029v2

Statement and scope

Equations (6)–(8), pp. 2–3. With binary entropy in bits $h(x)=-x{\log }_{2}x-(1-x){\log }_2(1-x)$, the scalar function is $f(c)=h((1-\sqrt{1-c^2})/2)$ on $0\le c\le 1$. It is increasing and convex. A Euclidean unit two-qubit vector with amplitude matrix $X$ has marginal entropy $f(2|\det X|)$.