The past three years have encompassed a meteoric rise of gravitational-wave astronomy with the activation of second generation gravitational-wave interferometers and the subsequent direct detection of GW150914 --- a gravitational-wave transient from a merging binary black hole. To date, two observing runs have been conducted, the second of which inaugurated a three instrument, worldwide network. I will report the key results driving the birth and growth of gravitational-wave astronomy: stellar mass black hole binaries and their measured masses and spins, the implications for compact binary astrophysics, and the foundation for future population studies. August of 2017 also added a highly anticipated component to multi-messenger astronomy. GW170817, the first binary neutron star detected with gravitational waves, kicked off a monumental joint electromagnetic and gravitational-wave observational campaign --- I will highlight ongoing studies of this watershed event. Finally, I will review the progression towards a more sensitive gravitational-wave network of up to five interferometers and prospects for compact binary detection in the next few years.

]]>We'll discuss fundamentals of science as applied to fundamental science in high-energy particle physics at the LHC. After a stroll through the garden of the LHC's main accomplishment, we'll wander through a dark forest of what is beyond until we make out the light from the prairie of high-precision.â

]]>Cold dense quark matter is a superfluid, but not quite the

familiar one we learned about in textbooks. Instead, it is a

"topologically-enriched" superfluid. I'll explain how to derive a

local effective action for this gapless phase of matter, which

involves coupling the superfluid to a topological quantum field theory

(TQFT). Along the way we'll talk about continuum "BF" actions for

four-dimensional discrete gauge theories, as well certain peculiar

five-dimensional cousins of these TQFTs relevant for our superfluids.

This talk is a more technical follow-up to a talk from two weeks ago,

but will be aimed to be followable by people who didn't attend the

first talk.

Correlated defects are responsible for the functional properties of many materials that underpin energy-related technologies. Single-crystal diffuse scattering using x-rays or neutrons is a powerful probe of short-range order in crystalline lattices, but its use has been limited by the experimental challenge of collecting data over a sufficiently large volume of reciprocal space and the theoretical challenge of modeling the results. However, instrumental and computational advances at both x-ray and neutron sources now allow the efficient measurement and rapid transformation of reciprocal space data into three-dimensional pair distribution functions, providing model-independent images of nanoscale disorder in real space. By eliminating Bragg peaks before the transformation, 3D-âPDF measurements image defect-defect correlations directly, displaying only the probabilities of interatomic vectors that deviate from the average structure. I will give examples of the use of this method to probe the structure and correlation length of order-disorder transitions in intercalation compounds, the length scale and dimensionality of nematic correlations in iron arsenides, and the defect correlations in a superionic thermoelectric.

This work was supported by the U.S. Department of Energy, Materials Science and Engineering Division.

Refreshments in atrium after the Colloquium.

A cell is the smallest unit of a freely living system. Our understanding of cells is measured by our ability to predict cellular behaviors in response to environmental changes and genetic manipulations. Traditionally, researchers strive to gain insights into cellular behaviors through characterizing the underlying molecular interactions. This âbottom-upâ approach however requires a macroscopic number of largely inaccessible parameters in order to be predictive. I will describe a complementary âtop-downâ approach based on quantitative phenomenology. Extensive quantitative experiments establish that the model bacterium E. coli organizes many of its behavioral responses in very simple manners in accordance to the rate of cell growth. The existence of these simple empirical relations (growth laws) despite myriads of complex molecular interactions is a striking manifestations of a tremendous degree of dimensional reduction occurring in living cells. I will describe how the growth laws can be used to make accurate predictions of cell behaviors without fitting parameters. I will also discuss how the magical dimension reduction can be accomplished by cells through clever strategy of gene regulation.

]]>Free massless scalars have a shift symmetry. This is usually broken by interactions, such that quantum corrections induce a quadratically divergent mass term. In the Standard Model this leads to the hierarchy problem, the question why the Higgs mass is so much smaller than the Planck mass. We present an example where a large scalar mass term is avoided by coupling the scalar to an infinite tower of massive states, obtained from a six-dimensional theory compactified on a torus with magnetic flux. We show that the shift symmetry of the scalar is preserved in the effective four-dimensional theory despite the presence of gauge and Yukawa interaction terms.

]]>Mass loss from exoplanets driven by stellar photo-ionizing fluxes may be a fundamental process setting the final state of planetary atmospheres and, therefore, habitability. In this talk I present new results from 3-D AMR multi-physics simulations exploring the processes and consequences of atmospheric photo-evporation including its observation signatures.

]]>Refreshments served at 3:15 p.m.

During the late nineteenth century, electrical entrepreneurs began to glut the direct-to-consumer medical market with a plethora of electrotherapy machines for curing deafness. They claimed their machines fostered a world of unbridled optimism for restoring bodies to health; in a few sessions, these machines could harness the power of electricity to jolt dead ears or apply a vibratory force to âbreak upâ deposits in the ear. Although ear specialistsâknown as âauristsââdenounced such âcure allâ treatments for deafness, electrical entrepreneurs made no demarcation between congenital and non-congenital cases of hearing loss, thus appealing to patient-consumers frustrated with traditional therapeutics. Electrotherapy devices also offered an effective but gentle remedy to those distrustful or skeptical of compressed powdered pills, nefarious nostrums, or other patented goods available for purchase. By the 1930s, a growing public awareness of medical fraud, combined with stricter federal regulation, led to the steady decline of electrotherapeutics usage in the home; while most mechanical deafness cures were dismissed by the American Medical Association and the Food & Drug Association as quackery in its finest forms, these devices highlight the fluid boundaries that existed between healthcare practices, and the many ways consumers attempted to regain control over their health. More broadly, these devices convey a broader historical context for understanding how and why deaf consumers attempted to cure or normalize their hearing loss.

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