论文标题

通过周期性驾驶弯曲低温温度的规则

Bending the rules of low-temperature thermometry with periodic driving

论文作者

Glatthard, Jonas, Correa, Luis A.

论文摘要

低温温度计的准确性存在严重的局限性,这对未来的量子技术应用构成了重大挑战。通过调整探针和样品之间的相互作用,可以操纵低温灵敏度。不幸的是,这些相互作用的可调性通常非常受限制。在这里,我们专注于一种更实用的解决方案来提高温度准确性 - 驱动探针。具体而言,我们解决了平衡样本中定期调制线性探针的极限周期。我们处理探针样本相互作用\ textit {恰好},因此,我们的结果对于任意低温$ t $和任何频谱密度有效。我们发现,弱近谐声调制强烈增强了低温测量值的信噪比,同时导致样品上的背部作用最少。此外,我们表明,近乎共鸣的驱动改变了在广泛温度下控制热灵敏度的功率定律,从而“弯曲”基本的精度限制,并实现更敏感的低温温度计。然后,我们专注于一个具体的示例 - 原子冷凝物中的杂质温度计。我们证明,定期驾驶允许从杂质原子的密度曲线中得出的亚纳米甲基温度估计值的几个数量级提高灵敏度。因此,我们提供了可行的升级,可以轻松地集成到低$ T $温度计实验中。

There exist severe limitations on the accuracy of low-temperature thermometry, which poses a major challenge for future quantum-technological applications. Low-temperature sensitivity might be manipulated by tailoring the interactions between probe and sample. Unfortunately, the tunability of these interactions is usually very restricted. Here, we focus on a more practical solution to boost thermometric precision -- driving the probe. Specifically, we solve for the limit cycle of a periodically modulated linear probe in an equilibrium sample. We treat the probe-sample interactions \textit{exactly} and hence, our results are valid for arbitrarily low temperatures $ T $ and any spectral density. We find that weak near-resonant modulation strongly enhances the signal-to-noise ratio of low-temperature measurements, while causing minimal back action on the sample. Furthermore, we show that near-resonant driving changes the power law that governs thermal sensitivity over a broad range of temperatures, thus `bending' the fundamental precision limits and enabling more sensitive low-temperature thermometry. We then focus on a concrete example -- impurity thermometry in an atomic condensate. We demonstrate that periodic driving allows for a sensitivity improvement of several orders of magnitude in sub-nanokelvin temperature estimates drawn from the density profile of the impurity atoms. We thus provide a feasible upgrade that can be easily integrated into low-$T$ thermometry experiments.

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