Quantum magnomechanical thermometry

温度的测量是科学许多方面的基础。温度计有两种，即所谓的“初级”温度计和“次级”温度计。初级温度计是基于基本的物理原理，可以在任何配备适当设备的实验室中重现。另一方面，辅助温度计必须根据主温度计进行校准，并且可以根据测量方式而变化。使用初级温度计显然是有利的，但在实践中，它们几乎从未使用过，因为它们昂贵且难以实现。一个简单，便宜的初级温度计将是一个有价值的市场补充。量子技术必须在极低的温度下运行，随着量子技术的重要性日益增加，对低温温度计的需求正在增长。虽然低温制冷技术在不断进步，但这些温度计却没有。事实上，用于低温的二次温度计正变得越来越昂贵，因为公司认识到需求的增长意味着他们可以对校准的二次温度计收取更高的价格。因此，在低温（< 1k）下，有用的初级温度计存在市场。在本项目中，我们将研究一种基于机械物体热噪声的低温初级温度计，基于量子散粒噪声的自校准。特别是，这将基于微波测量力学，使其非常适合低温环境。这将建立在基础工作的基础上，包括这个温度计的理论建议(马侬-声子量子相关测温，C.A. Potts…j.p Davis，物理Rev应用13,064001 2020)和我们最近对该系统力学的观察(动力学逆作用磁力学，C.A. Potts…j.p Davis，物理Rev X 11, 031053 2021)。

The measurement of temperature is fundamental to many aspects of science. There are two types of thermometers, so-called "primary" and "secondary" thermometers. Primary thermometers are based on fundamental physics that can be reproduced in any lab outfitted with the right equipment. Secondary thermometers, on the other hand, must be calibrated against a primary thermometer and can change depending on how they are measured. It is clearly advantageous to use primary thermometers, but in practice they are almost never used because they are expensive and difficult to implement. A simple, inexpensive primary thermometer would be a valuable addition to the market. With the growing importance of quantum technologies, which necessarily operate at extremely low temperatures, the demand for thermometers for use at cryogenic temperatures is growing. And while cryogenic refrigeration technologies are advancing, these thermometers are not. In fact, secondary thermometers for low temperatures are getting more expensive, as companies recognize that the growing demand means they can charge higher prices for calibrated secondary thermometers. Therefore, a market exists for useful primary thermometers at low temperatures (< 1 K). In this project, we will research a type of primary thermometer for low temperatures based on the thermal noise of a mechanical object, self-calibrating based on quantum shot noise. In particular, this will be based on a microwave measurement of mechanics, making it well suited to the cryogenic environment. This will build upon foundational work including a theoretical proposal for this thermometer (Magnon-Phonon Quantum Correlation Thermometry, C.A. Potts... J.P. Davis, Phys Rev Applied 13, 064001 2020) and our recent observations of mechanics in this system (Dynamical Backaction Magnomechanics, C.A. Potts... J.P. Davis, Phys Rev X 11, 031053 2021).