Quantum magnomechanical thermometry

温度的测量是科学的许多方面的基础。 有两种类型的温度计，即所谓的“初级”和“次级”温度计。 初级温度计基于基础物理学，可以在任何配备合适设备的实验室中复制。 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进行更改。 使用初级温度计显然是有利的，但在实践中，它们几乎从不使用，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市场上一个有价值的补充。 随着量子技术的重要性日益增长，量子技术必须在极低的温度下工作，对低温温度下使用的温度计的需求也在增长。 虽然低温制冷技术正在进步，但这些温度计却没有。 事实上，用于低温的二级温度计越来越贵，因为公司认识到，不断增长的需求意味着他们可以对校准的二级温度计收取更高的价格。 因此，在低温（< 1 K）下存在有用的初级温度计的市场。 本项目将研究一种基于机械物体热噪声的低温初级温度计，并基于量子散粒噪声进行自校准。 特别是，这将基于力学的微波测量，使其非常适合低温环境。 这将建立在基础工作的基础上，包括对这种温度计的理论建议（磁振子-声子量子相关温度计，C.A.波茨J. P. Davis，Phys Rev Applied 13，064001 2020）和我们最近对该系统力学的观察（Dynamical Backaction Magnomechanics，C.A.波茨J.P. Davis，Phys 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).