Novel Ferromagnetic Domains and Quantum Criticality with Bose Condensates in a Shaken Optical Lattice

摇动光学晶格中玻色凝聚的新型铁磁畴和量子临界性

• 批准号: 1511696
• 负责人: Cheng Chin
• 金额: $ 45.67万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1511696&HistoricalAwards=false
• 关键词: Novel; Ferromagnetic; Domains; Quantum; Criticality

While atoms have been long recognized as the building blocks of the world we see and the environment we live in, their behavior at low temperatures has never ceased to surprise us. Examples include superfluids that flow without friction and quantum magnetic materials that permit read, write and storage of ample information. A recent work led by the principal investigator showed that both superfluidity and ferromagnetism (the type of magnetism in bar magnets) manifest simultaneously in atoms when shaken back and forth by laser beams, like ping-pong balls riding the ripples on a lake. The intriguing dynamics of magnetic domains observed in the atomic superfluids suggests new strategies to efficiently store and process information in the quantum regime. The major science goal of this project is to simulate and study a new type of 4-pole magnet in a two-dimensional lattice, which promises much richer properties than the 2-pole (south and north pole) magnetism in conventional materials. The science program is complimented by an extensive outreach effort under the S.M.A.R.T. (Science, Mathematics, And Research Training) project. The proposed 4-pole magnetic phase will arise when an atomic superfluid is transferred into a two-dimensional shaken optical lattice, generated by overlapping two perpendicular optical standing waves. When the shaking amplitude is carefully tuned above a critical value, the superfluid is anticipated to split into 4 poles with ferromagnetic interactions. The formation of the 4-pole domain will be detected and studied by direct in situ imaging of the atomic sample. Compared to the conventional 2-pole magnets, the 4-pole magnets offer novel domain and vertex structures and are uniquely related to the four-color theorem in graph theory and the Potts model of statistical physics. Furthermore the phase transition into the ferromagnetic phase is associated with a variety of quantum phenomena, including Rashba superfluids, the Berezinskii-Kosterlitz-Thouless transition, and the Kibble-Zurek mechanism. Exploration of this quantum physics may have both academic and practical payoffs, including the development of a theoretical framework to understand quantum critical dynamics, simulations of N-pole ferromagnetic magnets, fabrication of programmable magnetic materials, and potentially even quantum information storage and processing.

虽然原子长期以来一直被认为是我们所看到的世界和我们生活的环境的组成部分，但它们在低温下的行为从未停止过让我们感到惊讶。例子包括无摩擦流动的超流体和允许读取、写入和存储大量信息的量子磁性材料。由首席研究员领导的最近的一项工作表明，当原子被激光束来回摇动时，超流性和铁磁性（条形磁铁中的磁性类型）同时表现出来，就像乒乓球在湖面上的涟漪上一样。在原子超流体中观察到的有趣的磁畴动力学表明了在量子体系中有效存储和处理信息的新策略。该项目的主要科学目标是模拟和研究一种新型的二维晶格中的4极磁体，这种磁体比传统材料中的2极（南极和北极）磁性具有更丰富的性质。科学计划得到了S.M.A.R.T.广泛的推广工作的补充。（科学，数学和研究培训）项目。当原子超流被转移到由两个相互垂直的光学驻波重叠产生的二维振动光学晶格中时，将出现所提出的四极磁相。当振动幅度被仔细调整到临界值以上时，预计超流体将分裂为具有铁磁相互作用的4个极。将通过原子样品的直接原位成像来检测和研究4极域的形成。与传统的2极磁体相比，4极磁体提供了新颖的畴和顶点结构，并且与图论中的四色定理和统计物理的Potts模型唯一相关。此外，铁磁相的相变与各种量子现象有关，包括Rashba超流体，Berezinskiii-Kosterlitz-无磁转变和Kibble-Zurek机制。对这种量子物理学的探索可能具有学术和实际的回报，包括开发理解量子临界动力学的理论框架，模拟N极铁磁磁体，制造可编程磁性材料，甚至可能是量子信息存储和处理。

项目成果

Universal Loss Dynamics in a Unitary Bose Gas

• DOI: 10.1103/physrevx.6.021025
• 发表时间: 2016-05-20
• 期刊: PHYSICAL REVIEW X
• 影响因子: 12.5
• 作者: Eismann, Ulrich;Khaykovich, Lev;Chin, Cheng
• 通讯作者: Chin, Cheng

Quantum Dynamics with Spatiotemporal Control of Interactions in a Stable Bose-Einstein Condensate

• DOI: 10.1103/physrevlett.115.155301
• 发表时间: 2015-10-05
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Clark, Logan W.;Ha, Li-Chung;Chin, Cheng
• 通讯作者: Chin, Cheng