与玻色子库耦合的自旋链中局部灵敏度的流动
Flow of local sensitivity in a spin chain coupled to a bosonic bath
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中文总结 AI 辅助
研究自旋链与玻色子库耦合时对编码参数局部灵敏度的流动，通过分析耦合对称性及不同耦合方式，发现霍斯坦耦合和杰恩斯 - 卡明斯耦合对灵敏度传递有不同影响，库频谱决定灵敏度能否返回自旋，还指出传输寄存器失敏情况。
中文摘要 AI 辅助
我们研究了由量子费希尔信息捕获的对编码参数的局部灵敏度如何在自旋链、耦合玻色子库及其量子关联之间流动，其中我们将库视为超出林德布拉德近似的完整多体量子系统。我们分析了耦合对称性如何直接在哈密顿量层面确定离去灵敏度的归宿。我们考虑了保持总激发数的激发交换杰恩斯 - 卡明斯耦合和自旋 - 激发守恒的霍斯坦耦合。我们发现霍斯坦耦合使库没有关于相位的一阶信息，并将损失的灵敏度完全存储在自旋 - 库关联中，而杰恩斯 - 卡明斯耦合将这种灵敏度传递给库，对于单个激发是完全传递。然后库的频谱决定了灵敏度是否会回到自旋。当耦合系统频率有共同周期时，它会完全周期性地恢复，但当那些频率分散时，离去的份额会在库模式中去相位且不再返回。我们注意到，一个传输的计量寄存器失去的灵敏度比其到达保真度所暗示的要多。
英文摘要
We study how local sensitivity to an encoded parameter, captured by the quantum Fisher information, flows between a spin chain, a coupled bosonic bath, and their quantum correlations, where we treat the bath as a full many-body quantum system beyond the Lindbladian approximation. We analyze how the coupling symmetry determines the destination of the departed sensitivity directly at the level of the Hamiltonian. We consider an excitation-exchanging Jaynes--Cummings coupling, which preserves the total number of excitations, and a spin-excitation-conserving Holstein coupling. We find that the Holstein coupling leaves the bath with no first-order information about the phase and stores the lost sensitivity entirely in spin--bath correlations, whereas the Jaynes--Cummings coupling passes this sensitivity to the bath, in full for a single excitation. The bath spectrum then governs whether the sensitivity ever returns to the spins. It revives fully and periodically when the coupled-system frequencies share a common period, but when those frequencies disperse the departed share dephases across the bath modes and never returns. We note that a transported metrological register loses more sensitivity than its arrival fidelity implies.
