Piñeiro A M, Genkina D, Lu Mingwu, Spielman I B
Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD 20899, United States of America.
New J Phys. 2019;21(8). doi: 10.1088/1367-2630/ab3840.
The creation of particle-antiparticle pairs from vacuum by a large electric field is at the core of quantum electrodynamics. Despite the wide acceptance that this phenomenon occurs naturally when electric field strengths exceed ≈ 10 Vm, it has yet to be experimentally observed due to the limitations imposed by producing electric fields at this scale. The high degree of experimental control present in ultracold atomic systems allow experimentalists to create laboratory analogs to high-field phenomena. Here we emulated massive relativistic particles subject to large electric field strengths, thereby quantum-simulated particle-antiparticle pair creation, and experimentally explored particle creation from 'the Dirac vacuum'. Data collected from our analog system spans the full parameter regime from low applied field (negligible pair creation) below the Sauter-Schwinger limit, to high field (maximum rate of pair creation) far in excess of the Sauter-Schwinger limit. In our experiment, we perform direct measurements on an analog atomic system and show that this high-field phenomenon is well-characterized by Landau-Zener tunneling, well known in the atomic physics context, and we find full quantitative agreement with theory with no adjustable parameters.
由强电场在真空中产生粒子 - 反粒子对是量子电动力学的核心内容。尽管人们普遍认为当电场强度超过约10 V/m时这种现象会自然发生，但由于在该尺度下产生电场存在限制，尚未通过实验观测到这一现象。超冷原子系统中高度的实验可控性使实验人员能够创建高场现象的实验室模拟。在此，我们模拟了处于强电场中的大质量相对论粒子，从而对粒子 - 反粒子对的产生进行量子模拟，并通过实验探索了从“狄拉克真空”产生粒子的过程。从我们的模拟系统收集的数据涵盖了从低于索末菲 - 施温格极限的低外加场（对产生可忽略不计）到远超过索末菲 - 施温格极限的高场（对产生的最大速率）的整个参数范围。在我们的实验中，我们对一个模拟原子系统进行了直接测量，结果表明这种高场现象可以通过原子物理领域中熟知的朗道 - 齐纳隧穿很好地表征，并且我们发现与理论完全定量一致，无需调整任何参数。
