Compass Lectures: Measuring gravitational frame-dragging on Earth with superfluid helium gyroscope скачать в хорошем качестве

Compass Lectures: Measuring gravitational frame-dragging on Earth with superfluid helium gyroscope

The Compass Lectures, Fall 2025 Lecture 8: How to measure gravitational frame-dragging on Earth with a superfluid helium gyroscope Speaker: Kai Ellers, PhD candidate in Physics Date: Friday, November 14, 2025 Talk Description: Einstein's theory of general relativity predicts that a rotating body, such as the Earth, will "drag" spacetime with it very slightly as it rotates. This effect was confirmed by the Gravity Probe B satellite, which showed that gyroscopes (imagine a spinning top) in Earth orbit change their orientation very slightly as they orbit. However, the magnitude of this effect has not been measured very precisely and a more precise measurement would allow us to put general relativity to the test more stringently than ever before. In this talk, I will explain how we can use superfluid helium to build an extremely sensitive gyroscope, which could be used to measure the frame-dragging effect at an unprecedented level of precision. In fact, I will argue that such a gyroscope could in principle measure a rotation rate as small as one revolution in the lifetime of the universe (~14 billions years)! I will also show that we can interpret this measurement as probing time differences as small as one millionth of a quecto-second (35 zeros after the decimal point!!). Finally, I will discuss the prospects for actually building such a device in the lab. Speaker Bio: Kai grew up in Maine and graduated from Amherst College with a double major in physics and math. In his undergraduate thesis he conducted experimental research on molecular nanomagnets, which have potential applications as qubits in a quantum computer. At Berkeley, he continued working as an experimentalist in Hartmut Haeffner's ion trapping group before deciding to become a theorist. Since 2022 he has been working with Birgitta Whaley on problems at the intersection of quantum mechanics and gravity. ==================================================== The Compass Lecture Series is a collection of research talks given by UC Berkeley Math and Physical Sciences (MPS) faculty, postdoctoral researchers, graduate students, and undergraduates. These talks are unique among UC Berkeley MPS lectures in that they are designed for an undergraduate audience. The goal of the lecture series is to introduce undergrads to as many areas of research as possible using language and concepts they can understand without having advanced prior knowledge of any particular field. The Fall 2025 lectures took place in a hybrid format on Fridays at 3:10 PM in 375 Physics North / 325 Physics South, UC Berkeley and via Zoom. ==================================================== Visit our website: https://compass.studentorg.berkeley.edu