Non-Equilibrium Interfaces in Strongly Interacting Fermi Gases

普通观众摘要：下一代技术，从磁悬浮高速列车和近乎无损的电力传输，到用于量子计算和计算机内存的更高性能的设备，将依赖于在微观层面上通过材料中电子之间的强烈相互作用实现更高性能的材料。然而，电子之间的强烈相互作用和关联产生了有利的性质，如更强的超导电性，这也给我们对这些材料的理解提出了新的挑战。特别是，当强关联物质被赶出平衡并与其他材料相互作用时，传统理论往往会崩溃，需要更强大的理论来处理强相互作用。在这项工作中，研究人员将测量强相互作用锂原子量子气体中的非平衡和输运性质，该气体模拟了强相互作用电子的量子行为。该项目旨在阐明强关联物质在失去平衡的情况下传输的基本物理学，现有的理论面临着最大的挑战。对这项研究有贡献的本科生和研究生将获得规划、指导和交流科学工作的技能，为在科学和技术工作中的职业生涯做准备。技术受众摘要：本研究计划将研究正常-超流体界面和强相互作用费米气体中的输运和非平衡动力学。该团队将实施锂-6原子的多区域陷阱，这将允许制备定义明确的非平衡初始态。研究人员将利用区域之间可控的势垒来启动朝着平衡的进化。初始化单独的正常和超流体区域将使该团队能够描述正常-超流体界面的传输特征，并观察界面的动力学。这些测量将为测试强相互作用系统的正常-超流和正常-超导体界面上的输运理论提供基准。准备一个与两个高度极化的储存区接触的样本区，将使研究人员能够测量超流体转变过程中的局部自旋输运性质。这样的测量将阐明超流和自旋输运之间的关系，配对关联在低温正常相中的作用，以及理论上的量子极限对输运的影响。这项工作中介绍的方法将为量子多体系统中一系列新颖的非平衡测量奠定基础。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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:Next-generation technologies, ranging from magnetically levitated high-speed trains and near-lossless power transmission, to higher-performance devices for quantum computing and computer memory, will depend on materials that, at the microscopic level, achieve higher performance through strong interactions between electrons in the material. However, the strong interactions and correlations between electrons that give rise to advantageous properties, such as more robust superconductivity, also present new challenges in our understanding of these materials. In particular, when strongly correlated materials are driven out of equilibrium and interfaced with other materials, conventional theories often break down, necessitating more powerful theories to handle strong interactions. In this work, the researchers will measure non-equilibrium and transport properties in a quantum gas of strongly interacting lithium atoms that models the quantum behavior of strongly interacting electrons. The project aims to elucidate the fundamental physics of transport in strongly correlated materials out of equilibrium, where existing theories face the greatest challenges. Undergraduate and graduate students contributing to the research will gain skills in planning, conducting, and communicating about scientific work, in preparation for careers in the scientific and technological workforce.Technical audience abstract:This research program will investigate transport and non-equilibrium dynamics at normal-superfluid interfaces and in strongly interacting Fermi gases. The team will implement a multi-region trap for lithium-6 atoms that will allow the preparation of well-defined non-equilibrium initial states. The researchers will employ controllable barrier potentials between the regions to initiate evolution towards equilibrium. Initializing separate normal and superfluid regions will enable the team to characterize transport at the normal-superfluid interface and to observe the dynamics of the interface. These measurements will provide benchmarks to test theories of transport at normal-superfluid and normal-superconductor interfaces for strongly interacting systems. Preparing a sample region in contact with two highly polarized reservoir regions will enable the researchers to measure local spin-transport properties across the superfluid transition. Such measurements will illuminate the relationship between superfluidity and spin transport, the role of pairing correlations in the low-temperature normal phase, and the effect of theorized quantum limits on transport. The approach introduced in this work will lay the foundation for a wide range of novel non-equilibrium measurements in quantum many-body systems.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.