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Colloquium

Colloquia are held on Thursdays at 4pm in room 4327 (building 4) of the Stevenson Science Center unless otherwise noted. Click here for directions, or phone the department. A reception with the speaker is held at 3:30pm in Stevenson 6333.

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Fall 2019

Thursday August 29th 2019 4:00 PM

Carlos Silva, Georgia Institute of Technology

Exciton polarons in two-dimensional organic-inorganic hybrid perovskites   (show abstract)

While polarons — charges bound to a lattice deformation induced by strong electron-phonon coupling — are understood to be primary photoexcitations at room temperature in three-dimensional hybrid organic-inorganic perovskite (HOIP) lattices, excitons are the stable quasiparticles in two-dimensional (2D) HOIPs. In this colloquium, I will address the question: are polaronic effects consequential in the exciton properties of these materials? Establishing the role of exciton polarons is a key fundamental issue for the rigorous description of the materials physics of 2D HOIPs. Based on our recent work, I will argue that exciton-polaron effects are manifested in the generally observed spectral fine structure comprised of four distinct, non-degenerate exciton resonances with constant inter-peak energy spacing that varies weakly upon substitution of organic cation. I will discuss the possible role of polaronic effects in establishing the finestructure along with alternative interpretations presented in the literature, including the effects of vibronic structure, Rashba splitting, and exchange interactions. Finally, I will address the consequences of polaronic effects on the quantum dynamics of these materials, relevant for applications in optoelectronics, such as light-emitting diodes, lasers, and polariton spontaneous coherence.

Host:R. Haglund

Thursday September 5th 2019 4:00 PM

Host:

Thursday September 12th 2019 4:00 PM

Scott Gaudi, Ohio State University

The Demographics of Exoplanets with WFIRST   (show abstract)

Measurements of the demographics of exoplanets over a range of planet and host star properties provide fundamental empirical constraints on theories of planet formation and evolution. I will discuss various efforts to measure and synthesize exoplanet demographics over broad regions of parameter space. Because of its unique sensitivity to low mass, long period, and free floating planets, microlensing is an essential complement to our arsenal of planet detection methods. I motivate, and provide expectations for, a microlensing survey with WFIRST, which when combined with the results from Kepler, will yield a nearly complete picture of the demographics of planetary systems throughout the Galaxy

Host:R. Scherrer

Thursday September 19th 2019 4:00 PM

FRANCIS G. SLACK LECTURE

Gerald Gabrielse, Trustees Professor and Director of the Center for Fundamental Physics at Northwestern University

Tabletop Searches for New Physics: a Tale of Two Electron Dipole Moments    (show abstract)

The fundamental mathematical description of physical reality, the Standard Model of Particle Physics, is the great triumph and the great frustration of modern physics. The great triumph is that all laboratory measurements are so far consistent with its predictions. The great frustration is that the Standard Model is clearly wrong, or at least significantly incomplete, in that it cannot account for many basic features of our universe. Measurements of the magnetic and electric dipole moments of the electron are crucial tests of the Standard Model. The measured magnetic dipole moment of the electron, the most accurately determined property of an elementary particle, is a test of the Standard Model's most precise prediction. The measured electric dipole moment of the electron tests the relative validity of the dramatically predictions of the Standard Model and of proposed improvements (e.g. supersymmetric models) This work was supported by the USA NSF.

Host:N. Tolk

Monday September 23rd 2019 4:00 PM

David Brin, Astrophysicist and Novelist

Our place in the Cosmos and Is Anyone Out There   (show abstract)

In both science and literature, the question of ‘others’ can be a mirror illuminating our own origins and plausible destinies. Are we a fluke? Might we be the first to navigate the minefield of existence? Astrophysicist and novelist David Brin will (briefly) survey both what we know and can speculate about life in the universe.

Host:R. Scherrer

Thursday September 26th 2019 4:00 PM

Les Johnson, NASA

Perspectives at 50: Space Science and Exploration Past, Present, and Future   (show abstract)

After the Apollo astronauts landed on the moon, the Space Race ended. The achievements in human space flight continued with the successes of Skylab, the Space Shuttle, and the International Space Station. With the retirement of the Space Shuttle fleet in 2011, America has been relying on Russia to carry its crews into space. Today, we are in the midst of a new Race to Space, with various commercial companies vying to claim the mantle of returning Americans to space in American-made rockets – providing revolutionary changes in the economics of space travel. A similar revolution in cost and capability is occurring in the robotic science community, allowing small businesses, universities, and non-profit research institutions to build and fly small spacecraft with capabilities rivaling those previously in the exclusive domain of governments. Today, for the first time since the 1960’s, there is a sense of unbounded optimism regarding the human future in space and our ability to send our robotic emissaries to the outer reaches of the solar system and beyond.

Host:N. Tolk

Thursday October 3rd 2019 4:00 PM

Host:

Thursday October 17th 2019 4:00 PM

WENDELL HOLLADAY LECTURE

Calen Henderson, IPAC-Caltech

Exoplanet Demographics from Kepler to WFIRST   (show abstract)

Over the past decade we have witnessed an acceleration in the pace of exoplanet detection and characterization. In particular, the Kepler space telescope facilitated the first large-scale studies of planet demographics, illuminating trends as a function of both planet radius and orbital period. The nature of the mission, however, led to these results being focused on planetary systems nearby to the Sun and to planets orbiting close-in to their host star. Yet more recently, gravitational microlensing has made myriad advancements with regard to characterizing individual planetary systems and exploring relatively unknown demographic regimes for planets orbiting at larger distances from their host stars, and located farther from the Solar neighborhood, including for free-floating planets not gravitationally tethered to any host star. I will highlight a handful of results, placing them in the context of what we have learned from Kepler. Then I will discuss the anticipated findings from WFIRST, NASA’s next flagship astrophysics mission, which will conduct a large-scale exoplanetary microlensing survey toward the center of the Milky Way.

Host:S. Jacklin

Thursday October 31st 2019 4:00 PM

Shriram Ramanathan, Purdue University

Quantum materials for brain and biological sciences   (show abstract)

The survival instinct is ubiquitous across organisms. Intelligence and cognitive capability however are correlated with the complexity of the nervous system, e.g. neuronal diversity and is enhanced by transfer of evolutionary knowledge and lifelong learning. We will consider examples where such organismic behavior can be realized in programmable quantum materials. Using the metastable perovskite nickelates as a model system, we will discuss insulator-metal transitions that are controlled by hydrogen doping highlighting recent discoveries on electronic structure modulation approaching the predictions of Verwey and Mott. From understanding the binding of the charge carriers to the lattice, we will describe two experiments in nickelates that mimic classic observations in biology, namely habituation in the sea slug Aplysia and ancestral intelligence in sharks. We will conclude with suggestions for future research to design AI machines that can exploit strong Coulomb interactions in ionic lattices.

Host:R. Haglund

Thursday November 7th 2019 4:00 PM

Prem Kumar, Northwestern University

Quantum Engineering: A Transdisciplinary Vision   (show abstract)

A global quantum revolution is currently underway based on the recognition that the subtler aspects of quantum physics known as superposition (wave-like aspect), measurement (particle-like aspect), and entanglement (inseparable link between the two aspects) are far from being merely intriguing curiosities, but can be transitioned into valuable, real-world technologies with performances that can far exceed those obtainable with classical technologies. The recent demonstration by the Chinese scientists of using a low-earth-orbit satellite to distribute entangled photons to two ground stations that are over a thousand kilometers apart is a stunning technological achievement—direct entanglement distribution over the best available fiber links is limited to a few hundred kilometers—and a harbinger of future possibilities for globally secure communications guaranteed by the power of quantum physics. Harnessing the advantages enabled by superposition, measurement, and entanglement (SME)—the three pillars of quantum physics—for any given application is what is termed quantum engineering in general. In many instances, however, the details of the underlying science (high-temperature superconductivity, photosynthesis, avian navigation, are some examples) is still not fully understood, let alone how to turn the partially understood science into a potentially useful technology. Nevertheless, it has become clear in the last few decades that quantum engineering will require a truly concerted effort that will need to transcend the traditional disciplinary silos in order to create and sustain new breeds of science and technology communities that will be equally versed in quantum physics as they would be in their chosen area of technology. In this talk, I will present my vision for unleashing the potential of quantum engineering, taking quantum communications and networking as an example.

Host:Sharon Weiss

Thursday November 14th 2019 4:00 PM

GUY and REBECCA FORMAN LECTURE

Deborah Berebichez

Outrageous Acts of Thinking   (show abstract)

Dr. Deborah Berebichez - Debbie is an expert in physics, science, innovation, embracing change, media communications and Internet of Things (IoT) and is an expert in Big Data, acting as a chief Data Scientist in NYC. Debbie is also the cohost of Discovery Channel’s Outrageous Acts of Science TV, where she uses her physics background to explain the science behind extraordinary engineering feats. Deborah has also appeared as an expert on the Travel Chanel, NOVA, CNN, FOX, MSNBC, and numerous international media outlets. She has a Ph.D. in physics from Stanford University: the first Mexican woman ever to do so.

Host:S. Hutson

Monday November 18th 2019 4:00 PM

Michael Tremmel, Yale University

Dynamic Duos: Supermassive Black Hole Pairs in Galaxy Mergers   (show abstract)

I present the first self-consistent prediction for the formation timescale of close Supermassive Black Hole (SMBH) pairs, the precursors to SMBH binaries, following galaxy mergers. Using Romulus25, the first large-scale cosmological simulation to accurately track the orbital evolution of SMBHs within their host galaxies down to sub-kpc scales, we predict that it is relatively rare for galaxy mergers to result in the formation of close SMBH pairs with sub-kpc separation and those that do form are often the result of Gyrs of orbital evolution. The likelihood and timescale to form a close SMBH pair depends on the mass and morphology of the merging galaxies. When galaxies are disrupted during a merger, their SMBHs are deposited on long lived, kpc-scale orbits that result in a population of ‘wandering’ SMBHs. I discuss the implications of these results for predictions of SMBH merger rates and examine the population of wandering SMBHs that our simulations predict should reside in massive halo

Host:K. Holley-Bockelmann

Thursday November 21st 2019 4:00 PM

Andrew Mugler, Purdue

Physics of collective cell sensing   (show abstract)

The physical limits to chemical sensing have been established and tested for single cells. However, recent experiments have demonstrated that cells can surpass these limits when they communicate. The theoretical limits to the precision of collective sensing are still poorly understood. In this talk, I will discuss three types of cell-cell communication (short-range, long-range, and self-communication) and describe how they alter the physical limits for fundamental sensory tasks, including gradient sensing by epithelial organoids and flow sensing by metastatic cancer cells. This work extends the study of sensory limits to multicellular ensembles and lays the blueprint for a generic theory of collective sensing.

Host:W. Holmes

Thursday November 28th 2019 4:00 PM

Thanksgiving Holidays

Thursday December 5th 2019 4:00 PM

Thomas Weiler, Vanderbilt University

Host:S. Hutson

Spring 2020

Thursday January 16th 2020 4:00 PM

Jessica Watkins, Vanderbilt University, Department of Teaching and Learning, Peabody College

Problematizing as a scientific endeavor: The importance of students identifying, articulating, and motivating problems   (show abstract)

There has been significant attention to students’ problem solving in physics, including what kinds of problems are useful to solve and how to help students learn to solve them. In this talk I argue for the importance of students authoring problems, as work that is central to the discipline of physics. This work, which we call problematizing, involves noticing an inconsistency or gap of understanding, identifying and articulating its precise nature, and motivating a community of its existence and significance. Drawing from scientists’ accounts and philosophy of science, I show the importance of problematizing in physics and how the development of a problem can be a significant scientific achievement. I then present two cases, one from elementary school and another from an introductory physics course, showing that students can problematize as part of their engaging in scientific inquiry. This perspective on the importance of problematizing holds implications for instruction, including the need to make space for students to articulate their confusion before there is a clear question and to acknowledge the role of uncertainty in scientific work.

Host:S. Hutson

Thursday January 23rd 2020 4:00 PM

Juan Carlos Idrobo, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

Honey, I Shrunk the Synchrotron, and the Result is an Electron Microscope: Sensing Magnetic Ordering, Electric Fields and Isotopes at the Atomic and Nanometer Level    (show abstract)

Scanning and transmission electron microscopes (S/TEM) are now ubiquitous in materials and biological sciences laboratories. They have radically enhanced our understanding of organic and inorganic matter with the successful development of aberration correctors [1,2], detectors with film-equivalent dynamical range [3], and more recently, with monochromators capable of achieving sub-10 meV energy resolution spectroscopy [4]. Here, I will present several examples demonstrating how we have exploited these capabilities and solved the pertinent experimental challenges to probe materials behavior at the nanometer and atomic scales. Specifically, I will show how by utilizing the phase of the electron probe one can reveal the anti-ferromagnetic order of complex-oxide materials [5], and explore the ferromagnetic strength at the interfaces of thin-film complex-oxide heterostructures [6] at the atomic level. I will also explain how the new generation of monochromators, combined with aberration-corrected STEM, can be used (i) as a primary thermometer (without requiring any previous knowledge of the sample) [7]; (ii) to study minute volumes of liquid water [8]; (iii) to detect site-specific isotopic labels in amino acids at the nanometer scale [9]. Additionally, I will show how one can detect the electric field of individual atomic columns of heavy and light elements, at the sub-Angstrom scale, by using an ultra-low noise SCMOS detector in the diffraction plane [10], and how one can detect anti-Fano resonances in plasmonic nanostructures [11]. Lastly, I will discuss potentially relevant new challenges that electron microscopy will need to resolve as it enters the forthcoming quantum information era. Could we detect a superconducting transition? Could we spectroscopically measure cryogenic temperatures with sub Kelvin precision? Could we measure the specific heat and thermal conductivity of materials? Could we detect minute concentrations of isotopic elements and perform radiocarbon dating at the nanoscale? These questions will be addressed and further elaborated during the presentation [12]. References: [1] J. Zach and M. Haider, Optik 99 (1995), p. 112. [2] O. L. Krivanek, et al, Institute of Physics Conference Series 153 (1997), p. 35. [3] A. R. Faruqi, R. Henderson, Curr. Opin. Struc. Biol. 17 (2007), p. 549. [4] O. L. Krivanek, et al., Phil. Trans. R. Soc. A 367 (2009), p. 3683. [5] J. C. Idrobo, et al., Adv. Struc. Chem. Img. 2 (2016), p. 5. [6] J. C. Idrobo, et al., unpublished (2020). [7] J. C. Idrobo, et al., Phys. Rev. Lett. 120 (2016), p. 095901. [8] J. R. Jokisaari, et al., Adv. Mater. 30 (2018), p. 1802702. [9] J. A. Hachtel, et al., Science 363 (2019), p. 525. [10] J. A. Hachtel, et al., Adv. Struc. Chem. Img 4 (2018), p. 10. [11] K. Smith, et al., Phys. Rev. Lett. 123, (2019), p. 177401. [12] This research was supported by the Center for Nanophase Materials Sciences, which is a Department of Energy Office of Science User Facility, and instrumentation within ORNL's Materials Characterization Core provided by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

Host:S. Pantelides

Thursday January 30th 2020 4:00 PM

Francis G. Slack Lecture

Barry Barish, Caltech

Probing the Universe with Gravitational Waves   (show abstract)

The discovery of gravitational waves, predicted by Einstein in 1916, is enabling both important tests of the theory of general relativity, and the birth of a new astronomy. Modern astronomy, using all types of electromagnetic radiation, is giving us an amazing understanding of the complexities of the universe, and how it has evolved. Now, gravitational waves and neutrinos are beginning to give us the opportunity to pursue some of the same astrophysical phenomena in very different ways, as well as to observe phenomena that cannot be studied with electromagnetic radiation. The detection of gravitational waves and the emergence and prospects for this exciting new science will be explored.

Host:S. Hutson

Thursday February 6th 2020 4:00 PM

Zina Cinker, National Graphene Association

From Hard Science to Next-Generation Tech: “The Graphene Story”   (show abstract)

How does a discovery go from lab research to a mass-produced product on the market? Commercializing a new material is an arduous journey that often takes about 30-40 years and involves an intertwined multi-stakeholder ecosystem. But where does science meet industry, investment, politics, society and psychology? In this talk, Zina Jarrahi Cinker shares her experience as the executive director of the U.S. national association for graphene —the 2D form of carbon that won the Nobel prize in 2010—. From the “hype” of the magical material, the “irrational exuberance” of the public and media, the hasty rush of global governments to the confusion and mistrust of billion-dollar industries, the inevitable “wild west” of no standards and the slow road to reputation recovery, she discusses what goes into commercializing a novel material. Sharing her experiences from the thrill of getting a PhD in physics and founding a consulting company to the challenges of being a woman in tech and a physicist lobbying on Capitol Hill, she tells the story of navigating the wondrous world of graphene.

Host:N. Tolk

Monday February 10th 2020 3:00 PM

Note change in Date and Time

Michael Murrell, Yale University

Broken Time Reversal Symmetry and the Efficiency of Biological Machines   (show abstract)

Biological systems are driven far from equilibrium through the consumption and dissipation of energy. However, it is unclear if the quality or efficiency of a biological process is enhanced the further the system is driven from equilibrium. To address this fundamental question, we develop experimental approaches to control the consumption of energy in biological systems, and theoretical approaches to measure its dissipation. Together, we gain an understanding of the regulation of energy during the assembly and performance of biological machinery across diverse time and length-scales. At the molecular scale, we develop technologies to precisely coordinate the de novo assembly of the protein-based mechanical machinery of the cell and control its consumption of chemical energy. In doing so, we seek to mimic the physical behaviors of living cells through modulating the internal, non-equilibrium “activity” in a non-living system. At the mesoscopic scale, we study the physical behaviors of cells and tissues by abstracting them as driven liquids, whose behaviors are described by models of capillarity and wetting adapted to reflect activity gleaned from molecular studies. At all scales, we apply frameworks from stochastic thermodynamics to estimate dissipation and the production of entropy using phase space fluxes and the breaking of time reversal symmetry. Together, these experimental and theoretical methods can enable an understanding of the relationship between dissipation and the efficiency of biological processes with significant impacts on phenotypic outcomes such as cancer metastasis, and wound healing.

Host:S. Hutson

Thursday February 13th 2020 4:00 PM

Tamara Bogdanovic, Georgia Tech

Supermassive black hole binaries in the era of multi-messenger astrophysics   (show abstract)

Supermassive black hole binaries (SMBHBs) are a product of galaxy mergers and progenitors of coalescing binaries, considered to be the prime sources for future gravitational wave (GW) detectors. Expectations for detection of gravitational radiation from SMBHBs have recently been raised by the success of the Laser Interferometer Gravitational-Wave Observatory, by the increasing sensitivity of the Pulsar Timing Arrays, and by selection of the Laser Interferometer Space Antenna for a large-class mission in the European Space Agency science program. In light of these developments, the rates at which SMBHBs form and evolve to coalescence remain important open questions in black hole astrophysics. Presently, the best avenue to address them is through electromagnetic observations and theoretical modeling. I will discuss how recent and anticipated advances in multi-messenger observational searches and modeling can help us to piece together the evolution of SMBHBs from galactic mergers all the way to the GW regime.

Host:J. Runnoe

Thursday February 20th 2020 4:00 PM

Thomas Ullrich, Brookhaven National Laboratory

The Glue That Binds Us - Probing Gluonic Matter With the World's First Electron-Ion Collider    (show abstract)

The proton and neutron are the building blocks of all atomic nuclei and make up essentially all the visible matter in the universe, including us. Experimental methods for peering inside protons and neutrons reveal a full-fledged symphonic orchestra within. These particles each consist of quarks that are held together by “sticky” particles, the appropriately named gluons. We have made huge strides in understanding the workings of quarks and gluons, but despite all this insight—and a good understanding of how individual quarks and gluons interact with one another—we, to our dismay, cannot fully explain how quarks and gluons generate the full range of properties and behaviors displayed by protons, neutrons and other hadrons. We will soon be able to break out of the fog. In this talk, I will discuss how the Electron-Ion Collider (EIC) with its unique capability to collide high-energy electron beams with high-energy proton or ion beams will address the most compelling unanswered questions about the elementary building blocks of the visible world and take us to the next frontier of physics, into a regime where the structure of matter is dominated by gluons. Moreover, polarized beams in the EIC will give unprecedented access to the spatial and spin structure of gluons and sea-quarks in the proton. In January 2020, the US Department of Energy selected Brookhaven National Laboratory as the site for the EIC and launched a planning and decision process that foresees entering operation at the end of the decade.

Host:S. V. Greene

Thursday February 27th 2020 4:00 PM

Nina Balke, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

A nanoscale view on electromechanical phenomena   (show abstract)

The ability to transform electrical energy into mechanical energy and vice versa is the foundation to many technologies in the area of information and energy, such as sensors, piezotronics, energy harvesting, piezoelectric, electrochemical, and polymer actuators, and artificial muscles. Despite the importance of electromechanical phenomena and numerous applications, fundamental interdisciplinary studies needed to understand, and control electromechanical phenomena on the nanoscale are lacking. Scanning probe microscopy (SPM) is well suited to measure local volume changes in the picometer range and has a lateral resolution of 10’s of nanometer which makes this an ideal technique to address electromechanical phenomena on the nanoscale. Despite the technical advances and the development of new SPM-based characterization techniques, the quantification of functional material parameters based on electromechanical phenomena is still elusive. The lack of quantitative and accurate measurement can also lead to the misinterpretation of relevant material physics. Only if quantitative material parameters can be extracted, can a correlation of nanoscale structure-function relationships be derived, and SPM can be integrated with techniques probing smaller or larger length and time scales as well as theoretical efforts for a full information integration across different disciplines. I will give an overview over which electromechanical phenomena can be probed quantitatively including electro-chemo-mechanical coupling to understand local electrochemical reactions in electrochemical capacitors. Then I will talk in depth about SPM and ferroelectric materials and how the quantitative measurement of piezoelectric material properties led to the discovery of layered 2D van der Waals ferroelectrics with highly unusual material properties and functionalities based on the presence of four polar phases and high ion conductivity. These materials demonstrate, for the first time, how physical order parameter can be controlled by ionic degrees of freedom which will open new concepts for functional heterostructures and electronic devices.

Host:S. Pantelides

Thursday March 5th 2020 4:00 PM

Spring Holidays

Thursday March 12th 2020 4:00 PM

CANCELLED

Saul Teukolsky

Testing the No-Hair Theorem with LIGO   (show abstract)

One of the key results of general relativity is that an astrophysical black hole in equilibrium is uniquely described by just two parameters, its mass and spin. This is called the No-Hair Theorem, a result that is not true in alternative theories of gravity. For many years, people have speculated about testing the theorem using gravitational waves from merging black holes. The merger forms a single black hole, which rings down emitting gravitational waves as quasi-normal modes, just like a struck bell. The theorem predicts that the measured mode frequencies and damping times should depend only on the mass and spin of the remnant black hole. For a long time, the consensus has been that this test will require the sensitivity of next-generation detectors. I will show that this consensus is wrong for a surprising reason, and report a test with data from GW150914, the first LIGO gravitational wave detection.

Host:R. Scherrer

Thursday March 19th 2020 4:00 PM

CANCELLED

Jeff Nico, National Institute of Standards and Technology

Measuring the Neutron Lifetime with a Cold Beam   (show abstract)

Neutron beta-decay is the simplest example of a semi-leptonic decay. A precise measurement of the neutron lifetime and λ, the ratio of axial vector and vector coupling constants of the weak interaction, allows for a determination of the CKM matrix element V_ud that is free from nuclear structure effects. The neutron lifetime provides an important test of unitarity and consistency of the Standard Model. The neutron lifetime is also the largest uncertainty in Big Bang Nucleosynthesis calculations of light element abundance. A new measurement of the lifetime using a beam of cold neutrons is ongoing at NIST. This method requires the absolute counting of the decay protons in a beam of precisely known neutron flux. Details of the technique will be discussed along with the broader context of neutron lifetime measurements.

Host:R. Scherrer

Thursday March 26th 2020 4:00 PM

CANCELLED

Jason Dexter, JILA, University of Colorado, Boulder

Imaging black holes: beyond the shadow   (show abstract)

In the past year, the longstanding goal of imaging a black hole has become reality. Two long baseline interferometry experiments operating at submillimeter and near-infrared wavelengths can now achieve microarcsecond scale angular resolution with sufficient sensitivity to detect synchrotron radiation from the Galactic center black hole, Sgr A*, and the supermassive black hole in M87. I will discuss the first results from each experiment, focusing on the opportunity to study accretion and jet physics in the immediate vicinity of an event horizon. I will outline the challenge of pushing towards tests aimed at determining whether black holes in the Universe are those predicted by General Relativity.

Host:J. Runnoe

Thursday April 2nd 2020 4:00 PM

CANCELLED

Julie Hogan, Bethel University

CMS Particle Flow: the LEGO tutorial and searches for new massive quarks   (show abstract)

The Compact Muon Solenoid detector at CERN's Large Hadron Collider uses a method called "particle flow" to interpret electronic signals in detector elements as particles like electrons or muons. This critical software is rarely learned in detail by young CMS researchers. I will share an engaging new hands-on tool developed for summer tutorials at Fermilab: the Particle Flow LEGO Experience. Then I will present recent searches for new physics particles called "vector-like quarks", which decay to a variety of massive quarks and bosons. In these searches we connect the particle flow information from showers of quark-based particles with machine learning algorithms to probe for evidence of new physics.

Host:S. Starko and R. Scherrer

Thursday April 9th 2020 4:00 PM

CANCELLED

Anthony Mezzacappa, Oak Ridge National Laboratory

Nucleosynthesis in Supernovae

Host:K. Holley-Bockelmann

Thursday April 16th 2020 4:00 PM

CANCELLED

Duncan Lorimer, Associate Dean for Research, West Virginia University

Fast Radio Bursts -- Nature's Latest Cosmic Mystery   (show abstract)

Fast Radio Bursts are millisecond-duration pulses of unknown origin that were discovered by an undergraduate student at West Virginia University in 2007. A decade on, with close to 1000 bursts currently known, fast radio bursts remain enigmatic sources which parallel the early days of gamma-ray burst astronomy in the early 1970s. I will tell the story of their discovery, summarize what we know about them so far, describe the science opportunities these bursts present, and make predictions for what we might learn in the next decade.

Host:S. Hutson