Ultrafast manipulation of the weakly bound helium dimer
Ultrafast manipulation of the weakly bound helium dimer
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DOI：
10.1038/s41567-020-01081-3
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发表时间：
2020-12
期刊：
影响因子：
19.6
通讯作者：
M. Kunitski;Q. Guan;H. Maschkiwitz;J. Hahnenbruch;S. Eckart;S. Zeller;A. Kalinin;M. Schöffler;L. Schmidt;T. Jahnke;D. Blume;R. Dörner
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文献类型：
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作者：
M. Kunitski;Q. Guan;H. Maschkiwitz;J. Hahnenbruch;S. Eckart;S. Zeller;A. Kalinin;M. Schöffler;L. Schmidt;T. Jahnke;D. Blume;R. Dörner
控制原子与外场之间的相互作用开辟了物理学的新分支，从强关联原子系统到理想玻色和费米气体以及Efimov物理。这种控制通常制备静止的或随时间变化的样品。相比之下，在分子物理学中，外部超短激光场被用来产生各向异性势，发射超快旋转波包并在自由空间中排列分子。在这里，我们结合联合收割机这两个制度的超快时间和低能量。我们将短脉冲激光应用于氦二聚体，一个弱束缚和高度离域的单束缚态量子系统。激光场局部地调谐两个氦原子之间的相互作用，赋予2 μ m的角动量，并唤起最初受限的解离波包。我们记录了这个波包的密度和相位的视频，因为它从小到大的核间距离传播。在大的核间距下，原子间的相互作用可以忽略不计，波包基本上是自由的。这项工作为波包动力学的未来层析成像铺平了道路，并为研究奇异的和难以接近的量子系统（如晕和Efimov态）提供了技术。
Controlling the interactions between atoms with external fields opened up new branches in physics ranging from strongly correlated atomic systems to ideal Bose and Fermi gases and Efimov physics,. Such control usually prepares samples that are stationary or evolve adiabatically in time. In contrast, in molecular physics, external ultrashort laser fields are used to create anisotropic potentials that launch ultrafast rotational wave packets and align molecules in free space. Here we combine these two regimes of ultrafast times and low energies. We apply a short laser pulse to the helium dimer, a weakly bound and highly delocalized single bound state quantum system. The laser field locally tunes the interaction between two helium atoms, imparting an angular momentum of 2ℏ and evoking an initially confined dissociative wave packet. We record a video of the density and phase of this wave packet as it propagates from small to large internuclear distances. At large internuclear distances, where the interaction between atoms is negligible, the wave packet is essentially free. This work paves the way for future tomography of wave-packet dynamics and provides the technique for studying exotic and otherwise hardly accessible quantum systems, such as halo and Efimov states.