RUI: Quantum Criticality in Rare-Earth and Actinide-Based Intermetallics

* 非技术性摘要 * 经典的相变，如水的冻结或沸腾，涉及热能。 这个个人研究者奖将支持量子相变的研究，发生在绝对零度，没有热量。 零点能与海森堡测不准原理有关，在这些跃迁中扮演着热的角色。 量子相变可以在令人惊讶的高温下显著影响物质的行为，并随着温度或磁场的变化导致体积的特征变化。 在NSF的支持下开发的高精度技术将用于搜索这些体积特征变化，以识别和表征潜在的量子相变。 可能发生在量子相变附近的新的物质状态将被寻找和研究。 本科生将参与这项工作的各个方面，无论是在校园内，并在前往国家实验室和其他合作机构。* 技术摘要 * 该个人研究者奖将支持几种稀土和锕系金属间化合物的量子临界性研究。 这些材料的热膨胀和磁致伸缩将使用在NSF支持下开发的电容式应变计进行测量。 相图将被绘制出来，这些材料的低温状态之间的相变将被表征。 这些膨胀测量将与Gruneisen分析中现有的比热测量相结合，以确定这些迷人材料的特征能量的体积依赖性。 将寻求量子临界的具体签名，例如当温度接近绝对零度时，Gruneisen参数的热膨胀和发散的符号变化。 可能发生在量子相变附近的新的物质状态将被寻找和研究。 本科生将参与这项工作的各个方面，无论是在校园内，并在前往国家实验室和其他合作机构。

****NON-TECHNICAL ABSTRACT****Classical phase transitions, such as the freezing or boiling of water, involve heat energy. This individual investigator award will support a study of quantum phase transitions which occur at absolute zero where there is no heat. Zero-point energy, associated with the Heisenberg Uncertainty Principle, plays the role of heat in these transitions. Quantum phase transitions can dramatically affect the behavior of matter at surprisingly high temperatures and lead to characteristic changes in volume as the temperature or a magnetic field changes. A high-precision technique, developed with NSF support, will be used to search for these characteristic changes in volume in order to identify and characterize the underlying quantum phase transition. Novel states of matter that may occur near quantum phase transitions will be sought out and studied. Undergraduate students will participate in all aspects of this work, both on-campus and during trips to national laboratories and other collaborating institutions. ****TECHNICAL ABSTRACT****This individual investigator award will support a study of quantum criticality in several rare-earth and actinide-based intermetallic compounds. The thermal expansion and magnetostriction of these materials will be measured using a capacitive dilatometer developed with NSF support. Phase diagrams will be mapped out and phase transitions between the low temperature states of these materials will be thermodynamically characterized. These dilation measurements will be combined with existing specific heat measurements in a Gruneisen analysis to determine the volume dependence of the characteristic energies of these fascinating materials. Specific signatures of quantum criticality will be sought, such as a sign change of the thermal expansion and divergence of the Gruneisen parameter as the temperature approaches absolute zero. Novel states of matter that may occur near quantum phase transitions will be sought out and studied. Undergraduate students will participate in all aspects of this work, both on-campus and during trips to national laboratories and other collaborating institutions.