发表机构
School of Physics and Materials Engineering, Hefei Normal University（合肥师范学院物理与材料工程学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文给出两量子比特纠缠形成度存在全局支撑仿射泛函的判据，等价于自旋翻转形式非退化；退化时态秩为二或三，扰动下纠缠度平方根下降，违反单侧Lipschitz界。
AI 中文摘要
我们给出了一个关于纠缠形成度在纠缠两量子比特态上存在全局支撑仿射泛函的判据。该泛函存在当且仅当自旋翻转双线性形式在该态的支持集上非退化，等价地，当且仅当与该支持集相关的最后一个并发度根非零。在这种情况下，纠缠形成度是局部Lipschitz连续的。在退化情形下，该态具有秩二或秩三，且其射影支持集与乘积态二次曲面相切。对于支持集外的适当扰动，纠缠形成度随混合参数的平方根而减小。我们显式地获得了首项。这种平方根减小违反了全局支撑仿射泛函所需的单侧Lipschitz界。
英文摘要
We give a criterion for the existence of a global supporting affine functional for the entanglement of formation at an entangled two-qubit state. It exists if and only if the spin-flip bilinear form is nondegenerate on the support of the state, or equivalently, if the last concurrence root associated with the support is nonzero. In this case the entanglement of formation is locally Lipschitz continuous. In the degenerate case the state has rank two or three, and its projective support is tangent to the product-state quadric. For suitable perturbations outside the support, the entanglement of formation decreases as the square root of the mixing parameter. The leading term is obtained explicitly. This square-root decrease violates the one-sided Lipschitz bound required for a global supporting affine functional.
Comments6 pages, Comments and collaboration are welcome
