JILA Auditorium
A Transportable Ytterbium Optical Lattice Clock with Eighteen Digits of Accuracy
When
-
Abstract:
We present the development and uncertainty evaluation of a transportable ytterbium optical lattice clock, achieving a total systematic uncertainty level of 3.7 ×10-18. We also report a field test of the clock after transporting it to Washington DC, demonstrating the clock’s reliability and readiness to contribute to scientific efforts such as the redefinition of the SI second and frequency-based measurements of Earth’s geopotential.
Visualizing Dynamics—A Role for Nonlinear Optical Spectroscopy in Energy Science
When
-
Abstract: The climate crisis is driving a new era of electrification around the globe. The decarbonization of transportation and industrial processes is expected to make a significant impact on the rate of climate change. For example, the electrification of refineries and the broader chemical industry has the potential to lead to major reductions in fossil fuel consumption and lower the production of harmful greenhouse gases contributing to climate change. New components including electrode materials and electrolytes are being discovered quickly and are ne
Effective field theories for phases of matter and cosmology
When
-
Abstract: I will review some modern applications of effective field theories outside their traditional particle physics domain. In particular, I will focus on spontaneous symmetry breaking for spacetime symmetries. The effective theories for the associated Goldstone excitations capture the low-energy/long-distance dynamics of a number of physical systems, from ordinary macroscopic media (solids, fluids, superfluids, supersolids) to more exotic cosmological ones.
Forming truncated accretion disks
When
-
Abstract: Black hole X-ray binaries and Active Galactic Nuclei transition through a series of accretion states in a well-defined order. During a state transition, the accretion flow changes from a hot geometrically thick accretion flow, emitting a power-law–like hard spectrum to a geometrically thin, cool accretion flow, producing black-body–like soft spectrum.
How were the most ancient objects in the universe formed?
When
-
Abstract: Ancient remnants from the early universe surround our galaxy, which you may know as globular clusters. Although now on their old age, understanding how these clusters were formed has the potential to provide insight into the physical conditions that prevailed during an epoch that cannot be directly observed. We now know that globular clusters can form during extreme episodes of star formation in the relatively nearby universe, but the actual physical conditions that give rise to globular clusters have vexed both observers and theorists for decades.
Predicting and harnessing unusual quantum effects in condensed-phase chemical processes via a synthesis of machine learning, path integration, and enhanced sampling
When
-
Abstract: Reliable theoretical prediction of complex chemical processes in condensed phases requires an accurate quantum mechanical description of interatomic interactions. If these are to be used in a molecular dynamics calculation, they are often generated “on the fly” from approximate solutions of the electronic Schrödinger equation as the simulation proceeds, a technique known as ab initio molecular dynamics (AIMD). However, due to the high computational cost of these quantum calculations, alternative approaches employing machine learning methods repre
Electron fractionalization in topological quantum materials
When
-
Abstract: The emergence of quasiparticles with fractional charge and fractional statistics is an essential feature of fractional quantum Hall states, which occur in two-dimensional electron gas under a strong magnetic field. An interesting question is whether fractional electron states can form spontaneously in quantum materials without the external magnetic field.