Creating stable superposed states of matter is one of the most intriguing aspects of quantum physics, leading to a variety of counterintuitive scenarios along with a possibility of restructuring the way we understand, process, and communicate information. Accordingly, there has been a major research thrust in understanding and quantifying such stable superposed states. Here, we propose and experimentally explore a quantifier that captures effective quantum coherence in an atomic ensemble at room temperature. The quantifier provides direct measure of ground-state coherence for electromagnetically induced transparency (EIT) along with a distinct signature of transition from EIT to Autler–Townes splitting regime in the ensemble. Using the quantifier as an indicator, we further demonstrate a mechanism to coherently control and freeze coherence by introducing an active channel that compensates decay in the system. In the growing pursuit of quantum technologies at room temperature, our results provide a unique way to phenomenologically quantify and coherently control quantum coherence in atom-like systems.

中文翻译：

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探测，量化和冻结原子热集成中的相干性

创建稳定的物质叠加态是量子物理学中最令人着迷的方面之一，它导致了各种违反直觉的情况，并且有可能重新构造我们理解，处理和交流信息的方式。因此，在理解和量化这种稳定的叠加状态方面已经有主要的研究方向。在这里，我们提出并实验性地探索了一个量词，该量词在室温下捕获原子集合中的有效量子相干性。量化器可直接测量电磁感应透明性（EIT）的基态相干性，以及从总体上从EIT过渡到Autler–Townes分裂状态的明显特征。使用量词作为指标，我们进一步展示了一种机制，可以通过引入可补偿系统衰减的有源通道来协调控制和冻结相干性。在室温下对量子技术的日益增长的追求中，我们的结果提供了一种独特的方法，可以用现象学方法量化和相干地控制类原子系统中的量子相干性。