论文标题
超过与碰撞温度法结合的热cramer-rao
Surpassing the Thermal Cramer-Rao Bound with Collisional Thermometry
论文作者
论文摘要
在碰撞的温度计中，与热浴接触的系统由Ancillas流探测。证明了连贯性和集体测量结果可以在某些特定状态下的独立和相同制备的（i.i.d.）辅助方面改善Fisher信息[Seah等，Phys。 Rev. Lett。，180602（2019）]。在这里，我们通过优化了可能的输入Ancilla状态（也针对块b = 2的块状状态）来完善对该计量学优势的分析。对于间接的测量相互作用和相干的能量交换通道，我们显示何时可以击败热cramér-rao结合，何时$ n> 1 $ n> 1 $ ancilla的集体测量可能会返回比单拷贝测量的优势。
In collisional thermometry, a system in contact with the thermal bath is probed by a stream of ancillas. Coherences and collective measurements were shown to improve the Fisher information in some parameter regimes, for a stream of independent and identically prepared (i.i.d.) ancillas in some specific states [Seah et al., Phys. Rev. Lett., 180602 (2019)]. Here we refine the analysis of this metrological advantage by optimising over the possible input ancilla states, also for block-i.i.d.~states of block size b=2. For both an indirect measurement interaction and a coherent energy exchange channel, we show when the thermal Cramér-Rao bound can be beaten, and when a collective measurement of $N>1$ ancilla may return advantages over single-copy measurements.
