论文标题
过渡金属原子的激光冷却
Laser Cooling of Transition Metal Atoms
论文作者
论文摘要
我们建议将激光冷却应用于许多过渡金属原子，从而使大量的骨气和费米原子气体冷却至超低温度。这些原子的非零电子轨道角动量意味着，即使是与原子过渡相关的光，也强烈依赖于原子 - 状态的光原子相互作用。同时，许多过渡金属原子在其低能状态下具有较小的磁偶极力矩，从而降低了偶极 - 松弛碰撞的速率。总的来说，这些功能为未来的超低原子研究提供了令人信服的机会。为了关注原子钛的情况，我们确定了亚稳态$ a ^5f_5 $状态作为支持$ j \ rightarrow j+1 $光学过渡，其属性类似于碱原子的D2过渡，并且适合激光冷却。该状态的高总角动量和电子自旋抑制了近乎闭合的光学转变为估计低于$ \ sim 10^{ - 5} $的分支比率的泄漏。按照钛的模式示例，我们确定了适用于scandium群（SC，Y，LA）激光冷却元件的光学转变，钛组（TI，ZR），钒组（V，NB），锰组（V，MN，TC）和Iron Group（Fe，fe，ru）。
We propose the application of laser cooling to a number of transition-metal atoms, allowing numerous bosonic and fermionic atomic gases to be cooled to ultra-low temperatures. The non-zero electron orbital angular momentum of these atoms implies that strongly atom-state-dependent light-atom interactions occur even for light that is far-detuned from atomic transitions. At the same time, many transition-metal atoms have small magnetic dipole moments in their low-energy states, reducing the rate of dipolar-relaxation collisions. Altogether, these features provide compelling opportunities for future ultracold-atom research. Focusing on the case of atomic titanium, we identify the metastable $a ^5F_5$ state as supporting a $J \rightarrow J+1$ optical transition with properties similar to the D2 transition of alkali atoms, and suited for laser cooling. The high total angular momentum and electron spin of this state suppresses leakage out of the the nearly closed optical transition to a branching ratio estimated below $\sim 10^{-5}$. Following the pattern exemplified by titanium, we identify optical transitions that are suited for laser cooling of elements in the scandium group (Sc, Y, La), the titanium group (Ti, Zr), the vanadium group (V, Nb), the manganese group (Mn, Tc), and the iron group (Fe, Ru).
