发表机构
Koç University; TU Wien; TÜBİTAK Research Institute for Fundamental Sciences (TBAE)（科奇大学; 维也纳工业大学; 土耳其科学技术研究委员会基础科学研究院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对单NV中心占空比受限干涉测量，提出退相干感知的相干控制，相比优化Ramsey方案实现25-27%灵敏度提升，并通过响应整形机制在短退相干时间下最大化增益。
AI 中文摘要
刺激响应性水凝胶将温度变化转换为可由氮-空位（NV）中心检测的磁场位移，从而在软材料和生物环境中实现纳米级测温。现有的水凝胶-纳米金刚石演示依赖于NV色心系综，其高光子通量伴随着梯度引起的不均匀展宽，而理想化的单NV方案则假设高通量荧光/ODMR读出。本文研究针对同类传感器的脉冲单NV路线，并探讨在相等检测光子预算下，考虑退相干的相干控制能否比优化的Ramsey询问方案提升测温性能。利用S形体积相变模型、偶极磁换能以及Lindblad主方程模拟，我们发现每次探测的灵敏度相比优化的Ramsey方案有可复现的25-27%的提升，即Fisher信息增益为57-60%（1.57-1.60倍）。该增益同样适用于光子归一化的Fisher信息。速率增益由测量占空比决定，即实验周期中用于积累信号而非初始化、读出或等待的时间比例，当开销或光学剂量约束主导周期时间时增益最大。优化轨迹揭示了一种响应整形机制，其中相位积累集中在序列末端附近，而一个闭式深度为二的解能够复现数值最优解并从解析上展示该机制。当退相干时间相对于测量开销或剂量限制的等待时间较短时，该优势最为显著，这正是水凝胶换能单自旋生物传感所针对的工作区间。
英文摘要
Stimulus-responsive hydrogels convert temperature changes into magnetic-field shifts detectable by nitrogen-vacancy (NV) centers, enabling nanoscale thermometry in soft and biological environments. Existing hydrogel-nanodiamond demonstrations rely on NV ensembles, whose high photon throughput is accompanied by gradient-induced inhomogeneous broadening, while idealized single-NV projections assume high-fluence fluorescence/ODMR readout. Here we study a pulsed single-NV route for the same class of sensors and ask whether decoherence-aware coherent control can improve thermometric performance over optimized Ramsey interrogation at equal detected-photon budget. Using a sigmoidal volume-phase-transition model, dipolar magnetic transduction, and Lindblad master-equation simulations, we find a reproducible 25-27% per-shot sensitivity gain over optimized Ramsey, i.e., a 57-60% gain in Fisher information (1.57-1.60). The same gain carries over to the photon-normalized Fisher information. The rate gain is governed by the measurement duty cycle, the fraction of the experimental cycle spent accumulating signal rather than initializing, reading out or waiting, and becomes largest when the overhead or optical-dose constraint dominates the cycle time. The optimized trajectories reveal a response-shaping mechanism in which phase accumulation is concentrated near the end of the sequence, and a closed-form depth-two solution reproduces the numerical optimum and exhibits that mechanism analytically. The advantage is most pronounced when the dephasing time is short compared with the measurement overhead or dose-limited waiting time, which is the operating regime targeted by hydrogel-transduced single-spin biosensing.
Comments24 pages, 12 figures, 4 tables
