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态光谱仪来提高佛罗里达大学（UF）和国家高磁场实验室（NHMFL）的现有光谱能力，该光谱仪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），这代表了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。关于这种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，我们知之甚少。因此，我们将开发一种光谱仪，能够解决与基于分子的纳米磁体的量子动力学有关的问题。将开发一种独特的仪器，能够实现：宽带连续波频率覆盖（8至500 GHz）;泵浦/探测和时域能力（高达300 GHz），亚微秒分辨率;以及对直流磁场方向的精确控制。实验将包括：快速通过和瞬态EPR研究磁量子隧穿在SMM;烧孔和双共振（ELDOR）的量子退相机制在纳米磁体的调查;和，最终，相干控制的量子自旋状态的SMM。新仪器将具有超出本提案所述研究范围的重要用途，例如，用于化学甚至生物学中应用的高分辨率高频EPR。PI将与NHMFL的研究人员合作，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 CAREER奖相关），这些活动将从该项目中受益匪浅。%该项目将建立在现有的实验能力，提供给研究人员在佛罗里达大学（UF）和国家高磁场实验室（NHMFL）通过开发一种新的仪器，将用于跨学科的合作研究和学生培训。实验将集中在单分子磁体（SMM）上，这代表了纳米科学的分子方法，在量子计算中具有潜在的应用。发展量子计算机的主要障碍是所谓的“退相干”问题，即“量子信息”不可逆地丢失到环境中，因为简单的事实是，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。这种退相干可以使用时间分辨的磁或光学测量技术来研究。对SMM的研究将需要覆盖微波频率范围的宽部分的能力，并且具有微秒量级的时间分辨率。此外，还需要利用强磁场控制SMM的量子态的能力。该项目将满足这些迫切需要，从而产生一种独特的实验仪器。PI将与NHMFL的研究人员合作，旨在为该国家设施的用户开发类似的功能。特别是，新的仪器将有重要的用途超出了对SMM的量子特性的研究，例如，高频电子顺磁共振（EPR）的化学甚至生物学问题的研究。最后，PI参与了一系列的推广/教育活动（与NSF CAREER奖有关），这些活动将从新工具的开发中受益匪浅。

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.