Exploring Excited-State 1D Dipolar Quantum Matter with Dysprosium Gases

摘要：这个研究项目是建立在PI和他的学生事先在NSF的支持下组装的机器上的——这个设备激励了世界各地的研究小组开发他们自己的类似实验。有了这个装置，PI正在探索受光限制只能在一个维度上运动的新型激发量子气体。这些气体——镝——是所有元素中磁性最强的。这使得研究小组可以利用镝原子之间巨大的棒状磁体相互作用来揭示奇异的量子物理学。限制气体在一个维度上移动会导致奇怪的现象。例如，原子通常是玻色子（具有整数自旋）或费米子（具有半整数自旋），但在一维中，玻色子可以像费米子一样工作，反之亦然。此外，固有的大量子效应阻止了像完美晶体那样在长尺度上具有秩序的相的出现。将这些气体激发到更高的能态应该会产生更奇怪的效应，但这些在很大程度上还没有被探索过。PI和他的团队的目标是创造这样的气体，因为他们怀疑这些量子系统不会热化。与咖啡和牛奶混合形成棕色液体不同，被激发的气体不会进入任何“混合”的热平衡。这样的系统可以教会我们如何通过抑制所有破坏信息的热化过程来保护量子气体或材料中存储的量子信息。更一般地说，该研究项目通过推动原子物理、量子光学和凝聚态物理方面的实验技术，探索了强相关物质的未知机制。因此，这个研究项目为研究生和本科生在斯坦福大学和PI最先进的激光实验室提供的形成性科学环境中提供了一个特殊的训练基地。这项研究涉及的物理和技术技能在各种重要的技术领域都有应用，最著名的是用于电信的激光和光子学，以及用于电子设备的先进新型固态材料。摘要：由于镝在一维空间中的特殊性质，可能会产生多种奇异的量子多体相和非平衡动力学。PI和他的学生通过使用他们独特的实验系统来解决非平衡一维偶极气体物理学的新方面，扩展了量子模拟的前沿。这些系统使PI的团队能够触及量子物理学中鲜为人知的热化方面。例如，关于量子可积性的分解和高激发量子多体系统的稳定，还有许多有待学习的地方。本方案资助两项基于一维偶极气体的新活动；PI和学生们正在：1)研究偶极相互作用如何改变luttinger -liquid-类基态和激发态，可能稳定后者以防止坍缩，从而产生新的“量子多体疤痕”态；2)将玻色子偶极量子牛顿摇篮的研究扩展到费米子，探讨量子热化如何依赖于量子交换统计；3)探索一维中存在远程偶极相互作用时多体局部化的可能破坏。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

General audience abstract:This research program is built on the machine the PI and his students assembled under prior NSF support---this apparatus has inspired research groups worldwide to develop their own similar experiments. With this apparatus, the PI is exploring new types of excited quantum gases constrained by light to move in only one dimension. These gases---of dysprosium---are the most magnetic of any element. That allows the team to exploit the large, bar-magnet-like interaction between the dysprosium atoms to reveal exotic quantum physics. Constraining the gas to move in one dimension results in bizarre phenomena. For example, atoms are normally either bosons (with integer spin) or fermions (with half-integer spin), but in one dimension, bosons can act like fermions and vice versa. Moreover, inherently large quantum effects prevent phases from emerging that possess order at long length scales, like perfect crystals do. Exciting such gases to higher energy states should yield even stranger effects, but these are largely unexplored. The PI and his team aim to create such gases because they suspect these quantum systems will not thermalize---i.e., unlike how coffee and milk mix to form a brown liquid, the excited gas will not come into any “mixed-like” thermal equilibrium. Such systems may teach us how to protect stored quantum information in quantum gases or materials by inhibiting all information-destroying thermalization processes. More generally, this research project explores uncharted regimes of strongly correlated matter by pushing the experimental state-of-the-art in atomic physics, quantum optics, and condensed matter physics. As such, this research program provides an exceptional training ground for graduate and undergraduate students in the formative scientific environment provided by Stanford University and the PI’s state-of-the-art laser lab. The research concerns physics and technical skills that find application in a variety of significant areas of technology, most notably lasers and photonics for telecommunications and advanced novel solid-state materials for electronic devices. Technical audience abstract:A diversity of exotic quantum many-body phases and nonequilibrium dynamics may arise from the unusual properties of dysprosium confined to one dimension. The PI and his students are extending the frontier of quantum simulation by using their unique experimental system to address novel aspects of the physics of out-of-equilibrium 1D dipolar gases. These systems allow the PI’s team to touch on poorly understood aspects of thermalization in quantum physics. For example, much remains to be learned about both the breakdown of quantum integrability and the stabilization of highly excited quantum many-body systems. The present program funds two new activities based on 1D dipolar gases; the PI and students are: 1) studying how dipolar interactions modify Luttinger-liquid-like ground and excited states, possibly stabilizing the latter against collapse to yield novel `quantum many-body scar'-like states; 2) extending their work on bosonic dipolar quantum Newton's cradles to fermions to ask how quantum thermalization depends on quantum exchange statistics; and 3) exploring the possible breakdown of many-body localization in the presence of long-range dipolar interactions in 1D.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.