发表机构
Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University（扬州大学物理科学与技术学院引力与宇宙学中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出纠缠提取的统一物理原理，推导最大可提取并发度的闭式表达式，揭示其与逆参与率的对应关系，表明该曲线可在超导电路量子电动力学实验中观测。
AI 中文摘要
我们提出了一种适用于纠缠提取的统一物理原理：两个局域探测器从量子场中可提取的纠缠，仅由该场的有效谱密度的局域化程度决定。我们在一个可解析求解的模型中验证了这一点，该模型包含两个耦合到漏能单模腔的量子比特，而该腔又耦合到连续电磁浴；我们以闭式形式推导了最大可提取并发度：$\u0393_{\text{max}}(Q)=2e^{-\u03c0/(2Q)}(1+e^{-\u03c0/(2Q)})/(1+3e^{-\u03c0/Q})$，其中$Q\equiv|\Delta|/\kappa$是量子比特-腔失谐量$\u0394$与腔线宽$\u03ba$的比值。在高$Q$极限下，$\u0393_{\text{max}}\simeq1-\u03c0^{2}/(16Q^{2})$，表明纠缠对腔损耗具有鲁棒性；在低$Q$极限下，该并发度指数衰减至零，与连续场的不可逆储库特性一致，此时无法获得最大纠缠。由于$Q$与有效谱密度的逆参与率（IPR）成正比，它是控制从基于确定性门的纠缠（$Q\to\infty$）到真空提取（$Q\to0$）过渡的唯一无量纲参数。我们的框架通过量化局域探测器可访问的真空关联份额，将Reeh-Schlieder定理操作化；还揭示了最大并发度与IPR的形式对应关系，类似于安德森局域化中的电导率-参与率关系。原则上，该预测的$\u0393_{\text{max}}(Q)$曲线可在超导电路量子电动力学实验中直接观测到。
英文摘要
We investigate the relation between spectral localization and entanglement harvesting in an analytically solvable model of two qubits coupled to a leaky single-mode cavity, which in turn couples to a continuous electromagnetic bath. We derive the no-jump concurrence at a prescribed reference gate time in closed form, $\mathcal C_g(Q)=2e^{-π/(2Q)}(1+e^{-π/(2Q)})/(1+3e^{-π/Q})$, where $Q\equiv|Δ|/κ$ is the ratio of the qubit-cavity detuning $Δ$ to the cavity linewidth $κ$. This reference time is inherited from the first maximally entangling unitary gate. At finite loss, $\mathcal C_g$ is the conditional concurrence at this prescribed readout time. In the high-$Q$ limit, $\mathcal C_g\simeq1-π^2/(16Q^2)$, while in the low-$Q$ limit it decays exponentially. For the Lorentzian spectral family, $Q$ is proportional to a detuning-normalized inverse participation ratio and simultaneously measures the balance between coherent exchange and collective decay. This yields a compact, model-specific description of the crossover from nearly unit conditional entanglement to overdamped suppression. The predicted $\mathcal C_g(Q)$ curve can, in principle, be examined in circuit QED with ideal monitoring and no-jump post-selection.
Comments9 pages;v2: added a schematic figure; fixed typos; revised some wording
