Yan L L, Wan W, Chen L, Zhou F, Gong S J, Tong X, Feng M
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Sci Rep. 2016 Feb 11;6:21547. doi: 10.1038/srep21547.
Phase transitions have been a research focus in many-body physics over past decades. Cold ions, under strong Coulomb repulsion, provide a repealing paradigm of exploring phase transitions in stable confinement by electromagnetic field. We demonstrate various conformations of up to sixteen laser-cooled (40)Ca(+) ion crystals in a home-built surface-electrode trap, where besides the usually mentioned structural phase transition from the linear to the zigzag, two additional phase transitions to more complicated two-dimensional configurations are identified. The experimental observation agrees well with the numerical simulation. Heating due to micromotion of the ions is analysed by comparison of the numerical simulation with the experimental observation. Our investigation implies very rich and complicated many-body behaviour in the trapped-ion systems and provides effective mechanism for further exploring quantum phase transitions and quantum information processing with ultracold trapped ions.
在过去几十年中，相变一直是多体物理学的研究重点。冷离子在强库仑排斥作用下，为通过电磁场在稳定约束中探索相变提供了一个极具吸引力的范例。我们在一个自制的表面电极阱中展示了多达十六个激光冷却的（40）Ca(+)离子晶体的各种构象，其中除了通常提到的从线性到锯齿形的结构相变外，还发现了另外两个向更复杂二维构型的相变。实验观测结果与数值模拟结果吻合良好。通过将数值模拟与实验观测进行比较，分析了离子微运动会导致的加热现象。我们的研究表明捕获离子系统中存在非常丰富和复杂的多体行为，并为进一步探索超冷捕获离子的量子相变和量子信息处理提供了有效机制。
