Upcoming Events

Hypothesized in the 1960s with the first evidence in the 1990s, the origin, quantity, and distribution of water on the Moon – and other airless bodies – is one of the most exciting questions in planetary sciences. Where did it come from? How much is there? What processes at what rates control the modern day distribution? And where *exactly* is the water? Fine-scale spatial knowledge of distribution is needed so that we can send landed missions to measure and sample for textures, elements, the presence of other volatiles, and isotopes to answer the questions above.

The remarkable precision of optical atomic clocks enables new applications and can provide sensitivity to novel and exotic physics. In this talk I will explain the motivation and operating principles of a “multiplexed" strontium optical lattice clock, which consists of two or more atomic ensembles of trapped, ultra-cold strontium in one vacuum chamber. This miniature clock network enables us to bypass the primary limitations to standard comparisons between atomic clocks and thereby achieve new levels of precision.

Earth's clouds are critical for weather and climate. Cloud formation in earth and other planetary atmospheres is a deceptively simple physical process of condensation. And yet clouds are very challenging to understand and predict due to the interplay of clouds with their environment. Cloud physics spans 12 orders of magnitude in space from the micro-scale of cloud drops to the planetary scale of the general circulation and a similar order of magnitude in time from fractions of a second of cloud drop collisions to centennial climate time scales.

Solar irradiance variability models supplement the measurement record by extrapolating the observations to broader spectral range and longer time periods than directly observed. Version 1 of the NASA-NOAA-LASP (NNL) solar irradiance variability models are observation-based models that prescribe change in TSI and SSI based on change in solar magnetic activity features called faculae, that enhance solar irradiance at most wavelengths, and sunspots that reduce solar irradiance.

The promise of universal quantum computing hinges on scalable single- and inter-qubit control interactions. Photon systems offer strong isolation from environmental disturbances and provide speed and timing advantages while facing challenges in achieving deterministic photon-photon interactions necessary for scalable universal quantum computing.

Surfaces and interfaces play a crucial role in chemical and physical phenomena, such as heterogeneous catalysis and reactions. At the surface or interface of water, the hydrogen-bonded network is abruptly interrupted, giving rise to fascinating interfacial properties. These specific properties are the driving forces for many biochemical, environmental and geochemical processes.

Remote sensing of the universe, including Earth and its atmosphere, largely relies on extracting information from photons/electromagnetic waves. To optimize information extraction, instruments and data analysis have to be looked at as a system. The colloquium will highlight examples of this systems approach to optical instrumentation that I have been involved in over the past few decades.

TBA

The evolutionary history, and likely habitability, of exoplanet atmospheres depends on the space weather of their host stars. Understanding the particle environment, including the wind density, magnetic field strength, and velocity field, impinging on exoplanet systems remains a significant open question. This unknown impacts the interpretation of exoplanet atmosphere observations and the ongoing search for biosignatures, with facilities like JWST.

TBA

For the overwhelming majority of organisms, effective communication and coordination are critical in the quest to survive and reproduce. A better understanding of these processes can benefit from physics, mathematics, and computer science – via the application of concepts like energetic cost, compression (minimization of bits to represent information), and detectability (high signal-to-noise-ratio). My lab's goal is to formulate and test phenomenological theories about natural signal design principles and their emergent spatiotemporal patterns.

Almost exactly 100 years ago, in the early months of 1926, Erwin Schrödinger published a series of four papers that would transform not only the prevailing theories of physics but also mankind’s very understanding of the nature of reality.

I will discuss the standards of time and frequency and how these standards have evolved over the centuries. I will present the current definitions of time and frequency and how these definitions are likely to evolve in the coming years.