Non-equilibrium dynamics of ultracold neutral plasmas

超冷中性等离子体架起了原子物理和等离子体物理以及原子物理和凝聚态物理之间的传统界限。这项实验研究计划集中于探索超冷中性等离子体的早期非平衡动力学，与逆电子和离子等离子体频率相比，时间较短。只有在这段时间里，离子和电子才会强烈耦合。这种耦合从根本上改变了离子-离子和电子-离子的相互作用。该项目将包括在这一制度下对三体重组率的首次直接测量。该速率的理论预测至少有一个数量级的不确定性，与温度和密度的精确比例也是未知的。这组高灵敏度、高分辨率的荧光技术能够测量离子系统中因与电子相互作用而产生的微小变化。该项目的更广泛影响集中在本科生的大量参与以及与高中理科教师的接触上。

Ultracold neutral plasmas bridge traditional boundaries between atomic physics and plasma physics and between atomic physics and condensed matter physics. This experimental research program focuses on probing the early-time non-equilibrium dynamics of ultracold neutral plasmas, at times short compared to the inverse electron and ion plasma frequencies. It is only during this time that both the ions and the electrons are strongly coupled. This coupling fundamentally changes the ion-ion and electron-ion interactions. The project will include the first direct measurements of the three-body recombination rate in this regime. Theoretical predictions of the rate are uncertain by at least an order of magnitude, and the exact scaling with temperature and density is unknown. The groups high-sensitivity, high-resolution fluorescence techniques enable measurement of small changes in the ion system that arise from interactions with the electrons. The broader impact of the program centers on a heavy involvement of undergraduates as well as outreach to high school science teachers.