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arXiv · 1910.07937

Quasirandom estimations of two-qubit operator-monotone-based separability probabilities

Paul B. Slater
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Abstract

We conduct a pair of quasirandom estimations of the separability probabilities with respect to ten measures on the 15-dimensional convex set of two-qubit states, using its Euler-angle parameterization. The measures include the (non-monotone) Hilbert-Schmidt one, plus nine others based on operator monotone functions. Our results are supportive of previous assertions that the Hilbert-Schmidt and Bures (minimal monotone) separability probabilities are $\frac{8}{33} \approx 0.242424$ and $\frac{25}{341} \approx 0.0733138$, respectively, as well as suggestive of the Wigner-Yanase counterpart being $\frac{1}{20}$. However, one result appears inconsistent (much too small) with an earlier claim of ours that the separability probability associated with the operator monotone (geometric-mean) function $\sqrt{x}$ is $1-\frac{256}{27 \pi ^2} \approx 0.0393251$. But a seeming explanation for this disparity is that the volume of states for the $\sqrt{x}$-based measure is infinite. So, the validity of the earlier conjecture--as well as an alternative one, $\frac{1}{9} \left(593-60 \pi ^2\right) \approx 0.0915262$, we now introduce--can not be examined through the numerical approach adopted, at least perhaps not without some truncation procedure for extreme values.

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Paul B. Slater. 2019-10-17. Quasirandom estimations of two-qubit operator-monotone-based separability probabilities. https://doi.org/10.1142/s021974992040002x

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