Hotter Christoph, Kosior Arkadiusz, Ritsch Helmut, Gietka Karol
Universität Innsbruck, Institut für Theoretische Physik, Technikerstraße 21a, A-6020 Innsbruck, Austria.
University of Copenhagen, Niels Bohr Institute, Blegdamsvej 17, Copenhagen DK-2100, Denmark.
Phys Rev Lett. 2025 Jun 13;134(23):233601. doi: 10.1103/w377-f9mx.
Because of the inherently probabilistic nature of quantum mechanics, each experimental realization of a dynamical quantum system can produce distinct measurement outcomes, particularly when coupled to a dissipative environment. Although quantum trajectories that lead to exotic, highly entangled states are possible in principle, their observation is typically hindered by extremely low probabilities. In this Letter, we present a method to significantly enhance the probability of generating highly entangled states in an ensemble of atoms undergoing collective superradiant decay on timescales much shorter than the individual atomic spontaneous emission rate. By analyzing an effective non-Hermitian Hamiltonian governing the dynamics between photon emission events, we identify the conditions necessary for these rare no-click trajectories to occur with higher likelihood. Crucially, our method relies on initializing the system in a nonclassical state, whose entanglement is amplified via the non-Hermitian superradiant dynamics. This approach provides a new route to creating highly entangled macroscopic states such as atomic Schrödinger cat states, paving the way for advancements in quantum metrology and other quantum technologies.
由于量子力学固有的概率性质，动态量子系统的每一次实验实现都可能产生不同的测量结果，尤其是当与耗散环境耦合时。尽管原则上可能存在导致奇异、高度纠缠态的量子轨迹，但它们的观测通常因概率极低而受阻。在本信函中，我们提出了一种方法，可在比单个原子自发发射率短得多的时间尺度上，显著提高在经历集体超辐射衰变的原子系综中产生高度纠缠态的概率。通过分析控制光子发射事件之间动力学的有效非厄米哈密顿量，我们确定了这些罕见的无点击轨迹更有可能出现所需的条件。至关重要的是，我们的方法依赖于将系统初始化为非经典态，其纠缠通过非厄米超辐射动力学得以放大。这种方法为创建高度纠缠的宏观态（如原子薛定谔猫态）提供了一条新途径，为量子计量学和其他量子技术的进步铺平了道路。
