Świsłocki Tomasz, Gajda Mariusz, Brewczyk Mirosław, Deuar Piotr
Institute of Information Technology, Warsaw University of Life Sciences - SGGW, ul. Nowoursynowska 159, 02786, Warsaw, Poland.
Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668, Warsaw, Poland.
Sci Rep. 2021 Mar 19;11(1):6441. doi: 10.1038/s41598-021-85298-z.
We study the spin distillation of spinor gases of bosonic atoms and find two different mechanisms in [Formula: see text]Cr and [Formula: see text]Na atoms, both of which can cool effectively. The first mechanism involves dipolar scattering into initially unoccupied spin states and cools only above a threshold magnetic field. The second proceeds via equilibrium relaxation of the thermal cloud into empty spin states, reducing its proportion in the initial component. It cools only below a threshold magnetic field. The technique was initially demonstrated experimentally for a chromium dipolar gas (Naylor et al. in Phys Rev Lett 115:243002, 2015), whereas here we develop the concept further and provide an in-depth understanding of the required physics and limitations involved. Through numerical simulations, we reveal the mechanisms involved and demonstrate that the spin distillation cycle can be repeated several times, each time resulting in a significant additional reduction of the thermal atom fraction. Threshold values of magnetic field and predictions for the achievable temperature are also identified.
我们研究了玻色原子自旋气体的自旋蒸馏，并在铬（Cr）和钠（Na）原子中发现了两种不同的机制，这两种机制都能有效地冷却。第一种机制涉及偶极散射到最初未占据的自旋态，且仅在阈值磁场以上冷却。第二种机制通过热云向空自旋态的平衡弛豫进行，降低其在初始组分中的比例。它仅在阈值磁场以下冷却。该技术最初在铬偶极气体中通过实验得到证明（Naylor等人，《物理评论快报》，115:243002，2015年），而在此我们进一步发展了这一概念，并深入理解了其中所需的物理原理和涉及的局限性。通过数值模拟，我们揭示了其中涉及的机制，并证明自旋蒸馏循环可以重复多次，每次都会使热原子分数显著进一步降低。还确定了磁场的阈值以及可达到温度的预测值。
