Presenter: Corrinne Mills, University of Illinois, Chicago.

Observations and simulations of the ultra-powerful bursts also provide insights into neutron star interior.įebruary 16 - 'Baryogenesis, new Higgs bosons, and what's next'

Recent numerical experiments shed some light on the extreme plasma physics in these events. Both mergers and isolated magnetar flares involve sudden heating up to MeV temperatures, creation of copious electron-positron pairs, and launching of ultra-relativistic outflows and shock waves. These cataclysmic events produce gravitational waves, neutrinos, and bright electromagnetic emission. Yet more powerful energy release occurs when two neutron stars merge. They are many orders of magnitude brighter than pulsars and produce electromagnetic waves with dimensionless strength parameter exceeding unity, resembling nonlinear optics phenomena in laser plasma. Similar explosions in distant galaxies are proposed as the engines of the mysterious fast radio bursts (FRBs). These magnetic explosions emit giant gamma-ray flares observed in our and neighboring galaxies. Some of them (called magnetars) generate explosions via sudden dissipation of magnetic energy with power up to 10 47 erg/s. Abstract: Neutron stars are by far the strongest known magnets in the universe.Presenter: Andrei Beloborodov, Columbia University.**Canceled - No Colloquium February 2** February 9 Joint Physics/APS Colloquium- 'Explosions from magnetized neutron stars”

As an example of a real-world intervention strategy, I will talk about the journey of this technology from a laboratory novelty to a leak detection network covering hundreds of square miles of infrastructure in one of the nation’s busiest oil and gas basins. Frequency combs emit hundreds of thousands of frequencies of light in exquisitely short, repeatable pulses, which enables broadband measurements of light-matter interaction at high accuracy, precision, and stability. In our laboratory, we are developing and harnessing the power of mode-locked frequency comb lasers to address these emerging challenges at the forefront of climate, energy, and environment. Abstract: High precision sensing in complex engineered and natural environments is crucial for resolving challenges in a wide range of applications including detecting greenhouse gas emissions, predicting wildland fire spread, designing hypersonic propulsion systems, and exploring exoplanet atmospheres.Presenter: Greg Rieker, Mechanical Engineering, University of Colorado Boulder.**Online Only - January 26 - 'Free range frequency combs – mobilizing frequency comb laser technology for energy and climate applications from atmospheric sensing to wildland fire research' Possible implications on halide perovskite properties will be discussed. We observe that the nominally cubic perovskite consists of dynamical, two-dimensional sheets of lower symmetry tetragonal regions of about 3 nm diameter with several picosecond lifetimes. We used X-ray and neutron diffuse scattering coupled with molecular dynamics to quantify the nature, size, and time scale associated with dynamical local order in CH 3NH 3PbI 3 and CH 3NH 3PbBr 3 perovskites. While the importance of lattice dynamics and dynamical (dis)order have been recognized in these materials, their nature is only poorly known and understood. These materials are a recently re-invigorated class of semiconductor that have demonstrated very high efficiencies for solar cells after just over a decade of research. In this talk, I will discuss the importance of local structure and how this can be quantified, and will demonstrate this for organic-inorganic hybrid halide perovskites. Accurately characterizing this local structure has proven challenging but recent advances in diffuse scattering (“between” Bragg peaks) has enabled local structure determination. This structure-function relationship applies in many materials classes, ranging from organics to Li-ion battery cathodes to perovskites. Abstract: Local atomic structure often differs from the global average structure as measured with diffraction and yet the local structure has a profound impact on properties.Presenter: Michael Toney, Chemical and Biological Engineering, University of Colorado Boulder.**No Colloquium** January 12 **Online Only - January 19 - ' The nature of local dynamic order in CH 3NH 3PbI 3 and CH 3NH 3PbBr 3' unless otherwise noted and will be in person at DUAN G1B20, as well as online via zoom and Youtube.

Pulsar lost colony reactor meltdown