Non-Equilibrium Interfaces in Strongly Interacting Fermi Gases

下一代技术，从磁悬浮高速列车和近无损电力传输，到用于量子计算和计算机存储器的更高性能设备，将取决于在微观层面上通过材料中电子之间的强相互作用实现更高性能的材料。然而，电子之间的强相互作用和相关性产生了有利的特性，例如更强大的超导性，也给我们对这些材料的理解带来了新的挑战。特别是，当强相关材料被赶出平衡并与其他材料接触时，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的量子气体中的非平衡和传输特性，该气体模拟强相互作用电子的量子行为。该项目旨在阐明强相关材料在平衡状态下传输的基本物理学，现有理论面临着最大的挑战。本科生和研究生的研究贡献将获得规划，进行和沟通有关的科学工作的技能，在科学和技术劳动力的职业生涯做准备。技术观众摘要：这个研究计划将调查运输和非平衡动力学在正常超流体界面和强烈相互作用的费米气体。该团队将为锂-6原子实施多区域陷阱，这将允许制备定义明确的非平衡初始状态。研究人员将在区域之间采用可控的势垒来启动向平衡的演变。初始化单独的正常和超流区域将使团队能够表征正常-超流界面处的传输并观察界面的动力学。这些测量将提供基准，以测试强相互作用系统在正常超流体和正常超导体界面处的传输理论。准备一个与两个高度极化的储层区域接触的样品区域，将使研究人员能够测量超流体过渡过程中的局部自旋输运特性。这样的测量将阐明超流性和自旋输运之间的关系，低温正常相中配对相关的作用，以及理论上的量子极限对输运的影响。这项工作中引入的方法将为量子多体系统中广泛的新型非平衡测量奠定基础。该奖项反映了NSF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: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.