Spin Tunneling, Decoherence, and Collective Effects in Nanomagnetic Systems

该奖项支持量子磁学领域的理论研究和教育。研究的重点是集体量子效应，纠缠和退相干在纳米磁性系统。主要研究内容包括：1）分子磁体中的集体量子效应，如自旋隧穿、电磁和声学超辐射的传播前沿。PI将使用偶极场的自组织思想来研究这些系统。自组织为大体积晶体中的自旋能级提供了共振条件，而与无序无关。它可以导致光子和声子的相干辐射由宏观数量的磁性分子。偶极场自组织模型最近开发的PI将扩展到描述这种效应在大块晶体的分子磁体。我们将研究自旋隧穿前沿的传播产生光子和声子超辐射的可能性。理论和相关的实验研究将密切互动，调查自旋隧道前沿。2)耦合到机械奈米共振器的自旋相干态与退相干。研究人员将在自旋-晶格相互作用的基本微观模型中，通过分析和数值方法研究自旋的纠缠和退相干。几何的作用将被阐明，核自旋的影响将被调查。这项研究将解决小型谐振器的品质因子，以及使用耦合到纳米谐振器的自旋作为量子位和超灵敏磁机械探针的前景。我们将研究弹性固体中量子自旋态与相干声子态的纠缠，这是由角动量守恒决定的。这项研究将促进对自旋传感器和纳米机械致动器的局限性的理解，以及守恒定律在自旋量子比特退相干中的作用。博士，本科生和高中生，包括女性和少数民族，将参与这项研究。CUNY Lehman College的Nanomagnetism Group与美国和国外的研究人员合作，组织关于纳米磁性的研讨会，并通过与当地学校保持联系参与社区外展。 在工业和学术界寻求职业生涯的年轻研究人员将接受传统和现代磁学以及计算方法的培训。与该小组有关的学生将通过纳米磁学小组组织的国际研讨会获得跨文化的经验。非技术总结该奖项支持磁学的理论研究和教育，重点是量子力学效应的作用，以及涉及大分子尺寸长度尺度的磁性系统和磁性现象，纳米磁性系统。它的重点是集体量子效应和自旋弛豫在纳米磁性系统。研究的两个主要方向是自旋系统的集体量子效应和含自旋纳米力学系统的量子动力学。 集体声学和电磁弛豫的分子磁体的研究将探索最近的想法的主要研究人员对自组织运动的自旋隧道和弛豫的前沿。 部分基于激光物理学方法的分析和数值计算工作将被用来理解自旋系统中的集体量子效应。这项研究可能会影响其他领域的物理学，处理两个层次的系统。它将有助于理解顺磁体中的自旋弛豫速率，以及从分子磁体晶体中获得相干亚太赫兹辐射的前景。由于固体中的自旋轨道效应而引起的磁弛豫和退相干是凝聚态理论中最基本的、很大程度上未解决的问题之一。 它们与自旋物理学的重要应用有关，如磁共振、磁记录、自旋电子学、量子计算和纳米机械致动器。 在制造和测量单个纳米磁体方面取得的进展引发了对这组问题的新兴趣。他们将通过分析和数值模型进行研究，涉及现实的磁-机械耦合，占总角动量守恒。博士，本科生和高中生，包括妇女和少数民族，将参与研究。CUNY Lehman College的Nanomagnetism Group与美国和国外的研究人员合作，组织关于纳米磁性的研讨会，并通过与当地学校保持联系参与社区外展。 在工业和学术界寻求职业生涯的年轻研究人员将接受传统和现代磁学以及计算方法的培训。与该小组相关的学生将通过纳米磁学小组组织的国际研讨会获得跨文化经验。

TECHNICAL SUMMARYThis award supports theoretical research and education in the field of quantum magnetism. Research is focused on collective quantum effects, entanglement and decoherence in nanomagnetic systems. The main thrusts include:1) Collective quantum effects in molecular magnets, such as propagating fronts of spin tunneling, electromagnetic and acoustic superradiance. The PIs will use the idea of self-organization of the dipolar field to study these systems. Self-organization provides a resonance condition for spin levels in a large volume of the crystal regardless of disorder. It can lead to coherent radiation of photons and phonons by a macroscopic number of magnetic molecules. A model of dipolar field self-organization recently developed by the PIs will be extended to describe this effect in bulk crystals of molecular magnets. The possibility of photon and phonon superradiance generated by propagating spin-tunneling fronts will be investigated. Theoretical and related experimental research will interact closely to investigate spin-tunneling fronts. 2) Coherent states and decoherence of spins coupled to mechanical nanoresonators. The PIs will study the entanglement and decoherence of spins by analytical and numerical methods within a fundamental microscopic model of spin-lattice interaction. The role of geometry will be elucidated and the effects of nuclear spins will be investigated. This research will address the quality factor of small resonators, as well as the prospect of using spins coupled to nanoresonators as qubits and ultra-sensitive magneto-mechanical probes. Entanglement of quantum spin states with coherent phonon states of an elastic solid, dictated by the conservation of angular momentum, will be investigated. This research will advance understanding of the limits of spin sensors and nanomechanical actuators, as well as the role of conservation laws in decoherence of spin-based qubits.Doctoral, undergraduate, and high-school students, including women and minorities, will be involved in the research. The Nanomagnetism Group at CUNY Lehman College collaborates with researchers in the U.S. and abroad, organizes workshops on nanomagnetism, and participates in the community outreach by maintaining contacts with local schools. Young researchers seeking careers in industry and academia will be trained in traditional and modern magnetism, as well computational methods. Students associated with the group will acquire cross-cultural experiences through international symposia organized by the Nanomagnetism Group.NON-TECHNICAL SUMMARYThis award supports theoretical research and education on magnetism with an emphasis on the role of quantum mechanical effects and on magnetic systems and magnetic phenomena which involve a length scale of the size of large molecules, nanomagnetic systems. It is focused on collective quantum effects and spin relaxation in nanomagnetic systems. The two main directions of the research are collective quantum effects in spin systems and quantum dynamics of nano-mechanical systems containing spins. Studies of collective acoustic and electromagnetic relaxation in molecular magnets will explore recent ideas of principal investigators on self-organized moving fronts of spin tunneling and relaxation. Analytical and numerical work, partially based on methods of laser physics, will be peformed to understand collective quantum effects in spin systems. This research may influence other areas of physics that deal with the two-level systems. It will help understand spin relaxation rates in paramagnets, as well as the prospect of obtaining coherent sub-Terahertz radiation from crystals of molecular magnets. Magnetic relaxation and decoherence due to spin-orbit effects in solids is among most fundamental, largely unsolved, problems of condensed matter theory. They are related to such important applications of spin physics as magnetic resonance, magnetic recording, spintronics, quantum computing, and nanomechanical actuators. Progress made in manufacturing and measurements of individual nanomagnets has ignited novel interest to this set of problems. They will be studied via analytical and numerical models involving realistic magneto-mechanical coupling that accounts for the conservation of the total angular momentum. Doctoral, undergraduate, and high-school students, including women and minorities, will be involved in the research. The Nanomagnetism Group at CUNY Lehman College collaborates with researchers in the U.S. and abroad, organizes workshops on nanomagnetism, and participates in the community outreach by maintaining contacts with local schools. Young researchers seeking careers in industry and academia will be trained in traditional and modern magnetism, as well computational methods. Students associated with the group will acquire cross-cultural experiences through international symposia organized by the Nanomagnetism Group.