The Emergence of Order in Ultracold Quantum Gases

我们周围的世界在不断变化。在这些动态中，可能会出现均衡秩序。但是，我们认定为生命本身的日常动态不可能在平衡中存在，因为(例如)离子浓度的梯度驱动神经的动作电位。在早期宇宙的宇宙学中，在经济市场动力学中，在重离子碰撞中的夸克-胶子等离子体中，在超导体的电阻率中，非平衡动力学的研究是多种多样的。*我们建议用超冷原子来研究出现有序的动力学。在过去的十年里，我们已经学会了如何研究中性钾的费米子同位素，它可以模拟电子在固体中的行为，甚至可以探索固体材料无法实现的场景。在这两种情况下，我们使用冷原子的“量子仿真”方法的优势是具有前所未有的调整和表征样本的能力。这使得我们探索的模型没有留下任何不确定性的余地；因此，观察到的任何现象或行为都与该模型有直接联系。*我们拟议的研究将解决关于非平衡量子动力学的三个公开问题。第一系列实验探索了强相互作用费米气体中自旋扩散的速率。我们希望解决目前关于维度对耗散的影响的争论。第二个系列的实验探索了p波关联的出现。我们的目标是创造一种具有独特和可控特性的超冷p波材料。P波超流体的激发包括马约拉纳态，它因在量子信息处理中的前景而被广泛寻求。第三条探索线使用新开发的显微镜来研究光晶体中原子的磁性有序。这项研究计划的成功将阐明粒子间的相互作用如何限制弛豫过程，产生磁性，并使新的超流态成为可能。用冷原子解决这些问题是一种高风险、高回报的实验，因为实验具有挑战性，理论很难理解，但潜在的好处是巨大的：我们的研究结果将直接洞察聚合模型的不可解动态。**

The world around us is constantly changing. Out of these dynamics, equilibrium order can emerge. But the everyday dynamics we identify as life itself cannot exist in equilibrium, because (for instance) gradients in ion concentrations drive action potentials in nerves. Non-equilibrium dynamics are studied diversely, in cosmology of the early Universe, in economic market dynamics, in quark-gluon plasma in heavy-ion collisions, and in the resistivity of superconductors.****We propose experiments with ultracold atoms that study the dynamics of emerging order. Over the past decade, we have learned how to study a fermionic isotope of neutral potassium, which can emulate the behaviour of electrons in solids, or even explore scenarios inaccessible with solid materials. In either case, the advantage of our “quantum emulation” approach using cold atoms in is an unprecedented ability to tune and characterise the sample. This leaves no room for uncertainty about the model we explore; so that any phenomena or behaviour observed has a direct connection to the model.******Our proposed research will address three open questions about non-equilibrium quantum dynamics. A first series of experiments explores the rate at which spin diffusion occurs in a strongly interacting Fermi gas. We hope to resolve a current debate regarding the effect of dimensionality on dissipation. A second series of experiments explore the emergence of p-wave correlations. We aim to create an ultracold p-wave material with unique and controllable properties. Excitations of p-wave superfluids include Majorana states, widely sought for their promise in quantum information processing. A third line of exploration uses a newly developed microscope to search for magnetic ordering of atoms in a crystal of light.******Success of this research program would elucidate how inter-particle interactions limit relaxation processes, give rise to magnetism, and enable new superfluid states. Addressing these issues with cold atoms is a type of high-risk, high-reward experiment, because the experiments are challenging and the theory is poorly understood, and yet the potential benefit is tremendous: the results of our investigations will yield direct insight into the unsolvable dynamics of paradigmatic models.**