IMR: Development of a Transient Spectrometer for Education and Research into Quantum Coherence in Molecular Nanomagnets

该项目将通过开发一种独特的宽带瞬变光谱仪来提高佛罗里达大学(UF)和国家强磁场实验室(NHMFL)现有的光谱能力，该仪器将用于跨学科合作研究和学生培训。实验将集中在单分子磁体(SMM)上，它代表了一种接近纳米和亚纳米科学的分子方法，在量子计算设备中具有潜在的应用。关于这样一个纳米磁体与其环境的耦合，以及这种耦合如何影响量子叠加态的相干性，人们知之甚少。因此，我们将开发一种能够解决与基于分子的纳米磁铁的量子动力学相关的问题的光谱仪。将开发一种独特的仪器，实现：宽带连续波频率覆盖(8至500 GHz)；具有亚微秒分辨率的泵浦/探测和时间域能力(高达300 GHz)；以及对直流磁场方向的精确控制。实验将包括：SMM中磁量子隧道的快速通过和瞬时EPR研究；纳米磁中量子退相机制的烧孔和双共振(Eldor)研究；以及最终对SMM量子自旋态的相干控制。新的仪器将在本提案所述的研究范围之外具有重要用途，例如用于高分辨率高频电子顺磁共振，在化学甚至生物中的应用。PI将与NHMFL的研究人员合作，目的是为该设施的用户开发类似的仪器。PI还参与了一系列外展/教育活动(与NSF职业奖项相关)，这些活动将从该项目中受益匪浅。%该项目将通过开发用于跨学科协作研究和学生培训的新仪器，建立在佛罗里达大学(UF)和国家高磁场实验室(NHMFL)研究人员现有实验能力的基础上。实验将集中在单分子磁体(SMM)上，这代表了纳米科学的一种分子方法，在量子计算中具有潜在的应用。量子计算机发展的主要障碍是所谓的“消相干”问题，即“量子信息”不可逆转地丢失到环境中，原因很简单，那就是将量子设备与其周围环境完全隔离是不切实际的，也是不可能的。这种退相干可以用时间分辨的磁测量或光学测量技术来研究。对SMM的研究将需要覆盖很大一部分微波频率范围的能力，并且时间分辨率在几分之一微秒量级。此外，还需要一种在强磁场下控制SMM量子态的能力。该项目将满足这些迫切的需求，从而产生一种独特的实验仪器。PI将与NHMFL的研究人员合作，目的是为这个国家设施的用户开发类似的能力。特别是，除了研究SMM的量子性质外，这种新的仪器还将具有重要的用途，例如用于化学甚至生物学问题的高频电子顺磁共振(EPR)研究。最后，和平协会参与了一系列外展/教育活动(与国家科学基金会职业奖有关)，这些活动将从新文书的开发中受益匪浅。

This project will advance existing spectroscopic capabilities at the University of Florida (UF) and the National High Magnetic Field Laboratory (NHMFL) through the development of a unique broadband transient spectrometer which will be used for interdisciplinary collaborative research and student training. Experiments will focus on single-molecule magnets (SMMs), which represent a molecular approach to nanoscale and sub-nanoscale science, with potential applications in quantum computational devices. Very little is known about the coupling of such a nanomagnet to its environment, and how this coupling affects the coherence of quantum superposition states. Thus, we will develop a spectrometer capable of addressing questions relating to the quantum dynamics of molecule-based nanomagnets. A unique instrument will be developed, enabling: broadband continuous-wave frequency coverage (8 to 500 GHz); pump/probe and time domain capabilities (up to 300 GHz) with sub-microsecond resolution; and precise control over the DC magnetic field orientation. Experiments will include: rapid passage and transient EPR studies of magnetic quantum tunneling in SMMs; hole-burning and double resonance (ELDOR) investigations of quantum dephasing mechanisms in nanomagnets; and, ultimately, coherent control of the quantum spin states of SMMs. The new instrumentation will have important uses beyond the scope of the investigations described in this proposal, e.g. for high-resolution high-frequency EPR with applications in chemistry and even biology. The PI will collaborate with researchers at the NHMFL with the aim of developing a similar instrument for users of this facility. The PI is also involved in a range of outreach/education activities (related to an NSF CAREER award) which will benefit immensely from this project.%%%This project will build upon existing experimental capabilities available to researchers at the University of Florida (UF) and the National High Magnetic Field Laboratory (NHMFL) through the development of a new instrument which will be used for interdisciplinary collaborative research and student training. Experiments will focus on single-molecule magnets (SMMs), which represent a molecular approach to nanoscale science, with potential applications in quantum computing. The major hurdle in the development of a quantum computer is the so-called "decoherence" problem, whereby "quantum information" is irreversibly lost to the environment due to the simple fact that it is both impractical and impossible to completely isolate a quantum device from its surroundings. This decoherence can be studied using time-resolved magnetic or optical measurement techniques. Studies of SMMs will require capabilities covering a wide portion of the microwave frequency range, and with time resolution on the order of a fraction of a microsecond. Furthermore, an ability to control the quantum states of SMMs with a strong magnetic field is also needed. This project will address these pressing needs, resulting in a unique experimental instrument. The PI will collaborate with researchers at the NHMFL with the aim of developing similar capabilities for users of this national facility. In particular, the new instrumentation will have important uses beyond the research into the quantum properties of SMMs, e.g. for high-frequency electron paramagnetic resonance (EPR) studies of problems in chemistry and even biology. Finally, the PI is involved in a range of outreach/education activities (related to an NSF CAREER award) which will benefit immensely from the development of the new instrument.