Colloquium

The colloquium is currently held at 4:30 PM on Tuesdays in Harriman 137. Cookies, tea and coffee are served from 4:15 PM outside the lecture hall.

Colloquium committee:Marivi Fernandez-Serra (Chair), Will Farr, Dmitri Kharzeev, Rouven Essig and Giacinto Piacquadio

Archive of colloquia from 1999 to the present

Spring 2023 Colloquia

Archived Colloquium Schedules

• Fall 2022 Colloquia

  Date	Speaker	Title & Abstract
  Sep 6	Barry Barish Professor of Physics, Emeritus, Caltech Distinguished Professor of Physics, UC Riverside Nobel Laureate, 2017	Inaugural C.N. Yang Colloquium Probing the Universe with Gravitational Waves The discovery of gravitational waves, predicted by Einstein in 1916, is enabling both important tests of the theory of general relativity, and represents the birth of a new astronomy. Modern astronomy, using all types of electromagnetic radiation, has giving us an amazing understanding of the complexities of the universe, and how it has evolved. Now, gravitational waves and neutrinos are beginning to provide 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.
  Sep 13	Chang Kee Jung Stony Brook University	Chair's Colloquium
  Sep 20	--	No colloquium.
  Sep 27	--	No colloquium.
  Oct 4	Mariangela Lisanti Princeton	Galactic Probes of Fundamental Dark Matter Physics The hypothesis of Cold Dark Matter (CDM) has been spectacularly confirmed on the largest scales of the Universe and must now be stress-tested on galactic scales. Many well-motivated and generic alternatives to CDM can leave spectacular signatures on precisely these scales, affecting the evolution of galaxies as well as their population statistics. Excitingly, over the course of the next decade, a flood of astrophysical data will open the possibility of searching for these distinctive imprints and shedding light on key questions about dark matter. In interpreting such results, systematic studies using both semi-analytic codes and numerical simulations will play a critical role in robustly disambiguating dark matter signals from other standard baryonic processes. As a concrete example in this talk, I will describe the consequences for galaxy formation when new forces mediate interactions between dark matter particles, highlighting key observables for future studies.
  Oct 11		Fall Break. No colloquium.
  Oct 18	Peter Denton Brookhaven National Laboratory	Knowns and Unknowns in Neutrinos In particle physics there exist two regions: the Standard Model which is fairly complete and the new physics sector which is completely unknown. Inbetween and overlapping with both of these is neutrino physics. Neutrinos exist within the Standard Model but are not explained by it due to the discovery of neutrino oscillations. In this colloquium I will discuss where we stand with neutrino oscillations, where we might go with them, and how we might learn about the nature of neutrinos.
  Oct 25	Talat Rahman University of Central Florida	The Importance of Being Imperfect: Defected 2D Materials for a Sustainable Future In the pursuit of a sustainable future, the last decade has seen a concerted effort in accelerating the discovery of materials for energy needs, thanks to a large extent to the Materials Genome Initiative. In this talk I will focus on few 2-dimensional materials which have captured our imagination. As with graphene, another common lubricant, molybdenum disulphide (MoS2) shows remarkable optical properties when peeled off as single sheet. I will show how defects and dopants in single-layer MoS2 transform its electronic structure so that it turns into a catalyst for CO hydrogenation. Even more interesting is the case of another 2D material, good old hexagonal boron nitride (h-BN), an avowed insulator. Defects, however, can transform it into a material that, on the one hand, captures and converts CO2 to value added products and, on the other, functions as a single photon emitter akin to NV centers in diamond. With a focus on electronic structural modulations of the local environment, I will draw comparisons with experimental observations made in collaborative work.
  Nov 1	Robert Crease Stony Brook University	The Leak: The Life and Untimely Death of Brookhaven's High Flux Beam Reactor In 1997, a small leak of tritium-containing water from the spent fuel pool of the HFBR (High Flux Beam Reactor) triggered a media and political firestorm that resulted in the reactor's shutdown and calls to close the laboratory. A quarter-century later, the episode embodies the dynamics of controversies in which fears and political agendas disrupt serious discussion and research of vital issues. Robert P. Crease is a Professor in and Chair of the Stony Brook Department of Philosophy. For 22 years he has written a column for Physics World, "Critical Point," on the historical and philosophical dimensions of science. He won the 2021 Institute of Physics Kelvin Medal for "describing key humanities concepts for scientists, and explaining the significance of key scientific ideas for humanists." His most recent book (with Peter Bond) is The Leak: Politics, Activism, and Loss of Trust at Brookhaven National lLaboratory (MIT Press).
  Nov 8		Election Day. No colloquium.
  Nov 15	Jen Cano Stony Brook University	A New Era of Topological Materials Topology plays an important role in our understanding of quantum matter. The topological classification of electronic bands gives rise to “topological insulators.” These phases are not only mathematically elegant, but also exhibit unusual physical properties sought after for next generation quantum electronics. While the past decade marked the search for topological materials, the goal of the next decade will be to detect, engineer, and manipulate their properties. I will describe theoretical advances that have broadened the classification of topological phases, giving rise to new probes and materials. Finally, I will introduce “topological twistronics” as a novel tuning knob to manipulate these exotic phases of matter.
  Nov 22		Thanksgiving Break. No colloquium.
  Nov 29	Giacinto Piacquadio Stony Brook University	Beauty (quarks) and the Higgs as Window into New Physics at the LHC Ten years ago, the discovery of the Higgs boson based on proton-proton collisions at the Large Hadron Collider provided experimental confirmation of the mechanism that gives elementary particles their mass. Today the Run-2 and Run-3 datasets, with their record-breaking proton-proton intensity and the highest collision energies ever produced by mankind, are enabling ATLAS and CMS experiments to perform measurements of the newly discovered particle with unprecedented precision, providing stringent tests for an increasing class of new physics models. After giving a general overview of the status of the field, I will explain why beauty quarks, the particles to which the Higgs boson decays more abundantly, represent such a challenging yet essential tool to study the Higgs boson, and how the deployment of machine learning tools is helping us extend the discovery reach to previously unexplored scenarios. Finally, I will discuss the prospects for Higgs boson measurements during the High-Luminosity phase of the LHC.
  Dec 6	Valeria Molinero University of Utah	Molecular Recognition of Ice by Proteins: From Ice Nucleation to Antifreeze Bacteria, insects and fish that thrive at subfreezing temperatures produce proteins that bind to ice and manage its formation and growth. Ice binding proteins include antifreeze proteins, that stop the formation of ice, and ice-nucleating proteins, that promote it. This presentation will discuss what makes proteins so outstanding at recognizing and binding ice, what distinguishes ice nucleating and antifreeze proteins, and how can we use that knowledge to engineer new molecules for a range of applications, from seeding clouds to induce precipitation to cryopreservation.

• Spring 2022 Colloquia

  Date	Speaker	Title & Abstract
  Feb 1	Navid Vafaei-Najafabadi Stony Brook University	Recruiting the 4th state of matter to miniaturize particle accelerators Particle accelerators have been an invaluable tool for scientific discovery and research. Future discoveries in high energy physics will require significantly more energetic particles than those currently produced. However, simply scaling the current machines to higher energies is a significant challenge because of their cost as well as the required space. A fundamental limitation that dictates the size of these machines is that the peak electric field used for accelerating particles must be below the damage threshold of the accelerating structures. Using a plasma, an ensemble of ionized atoms also known as the fourth state of matter, this limitation can be circumvented. In particular, high amplitude waves can be generated in a plasma using a high-power laser or a particle beam. The resulting structures have been shown to sustain accelerating fields that are hundreds of times higher than those currently generated in particle accelerators. In this talk, I will discuss how plasma waves are particularly well suited for accelerating electrons, the status of the state-of-art research, as well as the challenges that need to be overcome for plasma-based accelerators to form the foundation of next generation of high-energy particle beams.
  Feb 8	Wendy Freedman University of Chicago	This colloquium will be fully virtual. Increasing Accuracy in Measurements of the Hubble Constant: Is There Evidence for New Physics? An important and unresolved question in cosmology today is whether there is new physics that is missing from our current standard Lambda Cold Dark Matter (LCDM) model. Recent measurements of the Hubble constant, Ho -- based on Cepheids and Type Ia supernovae (SNe) -- are discrepant at the 4-5-sigma level with values of Ho inferred from measurements of fluctuations in the cosmic microwave background (CMB). The latter assumes LCDM, and the former assumes that systematics have been fully accounted for. If real, the current discrepancy could be signaling a new physical property of the universe. I will present new results based on an independent calibration of SNe Ho based on measurements of the Tip of the Red Giant Branch (TRGB). The TRGB marks the luminosity at which the core helium flash in low-mass stars occurs, and provides an excellent standard candle. Moreover, the TRGB method is less susceptible to extinction by dust, to metallicity effects, and to crowding/blending effects than Cepheid variable stars.   I will  address the current uncertainties in both the TRGB and Cepheid distance scales, the promise of upcoming James Webb Space Telescope data, as well as discuss the current tension in Ho and whether there is need for additional physics beyond the standard LCDM model.
  Feb 15	Jin Koda Stony Brook University	Increasing Accuracy in Measurements of the Hubble Constant: Is There Evidence for New Physics? Molecular gas and molecular clouds host virtually all star formation in the local Universe, and therefore their formation and evolution are the first step leading to star formation and galaxy evolution. In this talk, I will argue for long life and evolutional timescales of molecular gas and clouds (~>100Myr), as opposed to the recently-(again)-suggested short timescales (10-30Myr), by looking at their evolution through galactic rotation, i.e., how they form and evolve through spiral arms and inter-arm regions, in the Milky Way and in nearby galaxies. Although the popular spiral density-wave theory predicts a rapid phase transition from atomic to molecular and then to atomic phases through spiral arm passages, the observed fraction of molecular gas over atomic gas remains high even in the inter-arm regions in MW-like spiral galaxies. Hence, the molecular gas and clouds are not destroyed much toward the inter-arm regions. Recent ALMA data show diverse molecular structures in the inter-arm regions of nearby galaxies, many of which contain large masses. Their formation requires very long timescales (~100Myr) just to assemble the masses. If they are destroyed quickly in the short timescales, their formation would not catch up with the destruction; the galaxies should have much more atomic gas than the observed. The long life and evolutional timescale of molecular gas impacts the picture of star formation - the star formation has to be triggered in the long-existing molecular structures, rather than starting at an onset of gravitational collapse from diffuse atomic gas to dense molecular clouds. Until August 14, 2022, a recording of this colloquium may be accessed here, using the following passcode: 91.?S1YD
  Feb 22	Murray Holland University of Colorado Boulder	Extreme sensing, clocks, and squeezing atoms and molecules with light I will describe recent ideas for lowering the temperature of ensembles of ultracold atoms and molecules into the extreme quantum regime, for using interactions to entangle atoms and molecules into non-classical quantum states, and for using these non-classical states to realize quantum advantages for metrology, clocks, and matter-wave interferometry. One such topic is a new experimentally demonstrated idea for laser cooling by Sawtooth Wave Adiabatic Passage (SWAP). This is mostly relevant to atoms and molecules that possess narrow linewidth transitions, such as the ultranarrow clock transitions, and promises to be an important extension to the toolbox of AMO physics for laser cooling and trapping. We are exploring ways to use optical cavities and cavity-mediated interactions to entangle atoms so that we may improve optical clock performance, make repeated quantum measurements beyond the standard quantum limit, and continuously track squeezed quantum phases. These approaches take full advantage of the powerful combination of the extreme optical coherence that is possible using atomic clocks, with the rich possibilities offered by many-body physics that arises when the atoms interact strongly. Atomic clocks have already progressed to the point that understanding how to take advantage of quantum effects will be crucial in order to progress to the next generation of devices. Until August 21, 2022, a recording of this colloquium may be accessed here, using the following passcode: =3V&hEVn
  Mar 1		No colloquium.
  Mar 8	Laura Cadonati Georgia Institute of Technology	Exploring the cosmic graveyard with gravitational waves A new era in astrophysics has begun with the 2015 discovery of gravitational waves from the collision of two black holes in data from the Laser Interferometer Gravitational-wave Observatory (LIGO). The additional 2017 LIGO-Virgo detection of gravitational waves from the collision of two neutron stars in coincidence with a gamma ray burst and a kilonova, elevated multi-messenger astrophysics from concept to tool for discovery and exploration. Many more gravitational wave signals have been observed since then from collisions of compact binary coalescence, and gravitational waves are a new, important probe for understanding the universe, with a rich science potential ranging from astronomy to cosmology to nuclear physics. This talk will present a selection of the  latest results from LIGO and Virgo, with their GWTC-3 gravitational wave transient catalog, and an outlook for the next decade.
  Mar 22	Alexandra Gade Michigan State University	This colloquium will be fully virtual. The science of FRIB: From the nuclear many-body challenge to the origin of the elements in the Universe There are approximately 300 stable and 3,000 known unstable (rare) isotopes. Estimates are that over 7,000 different isotopes are bound by the nuclear force. It is now recognized that the properties of many yet undiscovered rare isotopes hold the key to understanding how to develop a comprehensive and predictive model of atomic nuclei, to accurately model a variety of astrophysical environments, and to understand the origin and history of elements in the Universe. Some of these isotopes also offer the possibility to study nature's underlying fundamental symmetries and to explore new societal applications of rare isotopes. This presentation will give a glimpse of the opportunities that arise once the Facility for Rare Isotope Beams (FRIB) comes online at Michigan State University in a few weeks. Until September 18, 2022, a recording of this colloquium may be accessed here, using the following passcode: &n5*qKQK
  Mar 29	Dmitry Tsybychev Stony Brook University	Experimental studies of the electroweak symmetry breaking at CERN Large Hadron Collider Understanding of electroweak symmetry breaking mechanism is one of the highest priority problems facing the field of high-energy physics and most importantly whether such breaking occurs solely through the weak interactions. The divergence of electroweak interactions in the Standard Model of particle physics, in particular, scattering of longitudinally polarized of heavy gauge bosons, at the TeV scale is solved by introduction of a Higgs boson. We will present studies of the electroweak symmetry breaking at ATLAS experiment at the Large Hadron Collider (LHC), operating at center-of-mass energies of 7-14 TeV, the highest collision energy in the world. Until September 25, 2022, a recording of this colloquium may be accessed here, using the following passcode: d?n9qHse
  Apr 5	Heather Gray Berkeley	Computing Challenges for Future Colliders — could quantum computing play a role? High-energy physics is facing a daunting computing challenge with the large and complex datasets expected from the HL-LHC in the next decade and future colliders to follow the LHC. The landscape of computing has been evolving rapidly and field of quantum computing in particular has been making dramatic progress in recent years. I will outline the challenges facing high-energy physics, provide a brief introduction to quantum computing focusing on recent progress and discuss recent work that may lead to solutions for high-energy physics.
  Apr 12	Dave Kawalll University of Massachusetts	An Anomaly in an Anomaly? First Results from the Fermilab Muon g-2 Experiment The Fermilab muon g-2 experiment recently released its first measurement of the magnetic behavior of the muon. Muons are like electrons, but heavier and short-lived. Their magnetic properties can be predicted with impressive, sub-ppm precision through the techniques of quantum field theory. An interesting feature is that an accurate prediction requires the addition of quantum corrections that arise due the interactions of the muon with all the other fundamental particles of nature such as electrons, photons, quarks, etc. Comparison of experimental results with theoretical predictions then serves as a powerful test of the completeness of the Standard Model of nature, and the long-standing discrepancy we observe might indicate the need for new physics. The concepts behind the Fermilab experiment and the many challenges it faces will be presented, along with the comparison with theory and future prospects. Until October 9, 2022, a recording of this colloquium may be accessed here, using the following passcode: CyYyXU$0
  Apr 19	Mark Palmer Brookhaven National Laboratory	An Energy Frontier Muon Collider: Progress Towards a Machine to Drive Particle Physics Discovery Muon colliders offer a unique path to multi-TeV, high-luminosity lepton collisions. Muon collisions with a center-of-mass energy of 10 TeV or above would offer significant discovery potential where the constituent collision energies exceed those of the LHC program by an order of magnitude. Significant progress on the fundamental R&D and design concepts for such a machine has led to a new international effort to assemble a conceptual design within the next few years. This effort will assess the viability of such a machine as a successor to the LHC program. The remaining challenges and the R&D required to deliver a complete machine description will be described. Until October 16, 2022, a recording of this colloquium may be accessed here, using the following passcode: b*&J29Z8
  Apr 26	John Wilkerson University of North Carolina	This colloquium will be fully virtual. Probing the elusive nature of neutrinos Neutrinos, enigmatic fundamental particles, were long assumed to be massless until a series of revolutionary experiments over the past two decades revealed that they actually exhibit complex behavior and must possess non-zero mass. From these and other recent measurements we know that neutrinos have minuscule masses, at least 500,000 times lighter than the electron. Yet we still do not know the neutrino’s actual mass nor why it is so light? Nor do we understand their fundamental nature, are they Dirac or Majorana particles? If neutrinos are their own antiparticles, Majorana neutrinos, then this would provide an explanation for their elusive lightness while at the same time offering a potential explanation of the universe’s observed matter - antimatter asymmetry. This talk will briefly review our current understanding of neutrinos, their role in cosmology, astrophysics, and fundamental interactions, and then address the questions of both how one “weighs” a neutrino and how to determine its Dirac or Majorana nature. The techniques and latest results from cosmology, direct kinematical methods, and double beta decay will be presented. Until October 23, 2022, a recording of this colloquium may be accessed here, using the following passcode: H4Uq.v$1
  May 3	Matthew Dawber Stony Brook University	Graduate Colloquium

• Fall 2021 Colloquia

  Date	Speaker	Title & Abstract
  Aug 31	Matthew Dawber Stony Brook University	Building better functional materials with advanced deposition and x-ray diffraction If the oft-quoted maxim in materials design is that “the whole is more than the sum of the parts”, it is also true that “the devil is in the details”.  In the case of ferroelectric oxides, this is especially true. Our work in building artificially layered heterostructure of these materials has shown that their key functional properties, including the nanoscale arrangement of electrical polarization and their ability to act as photocatalysts to generate hydrogen fuel, are determined by events that occur during their fabrication. They also depend strongly on tiny details such as the precise arrangement of atoms on their surfaces. Hence we will add to our list of handily appropriate sayings, “the journey is as important as the destination”.  Historically, the approach to material fabrication has largely been like taking a red-eye with your eyeshades on, you know where you started and where you land, but have very little idea about what happened in between. (It’s also pretty tedious and uncomfortable).  Through the use of synchrotron x-ray diffraction performed in-situ during growth and other dynamic processes we have begun to peel off the eyeshades, learning a great deal about the processes and also developing insight into how we can influence the processes at key points to greatly enhance the final properties of our materials. It’s a bit like being awake when the meal cart goes by, i.e., very much to your advantage!
  Sept 7	Chang Kee Jung Stony Brook University	Chairs Colloquium
  Sept 14	Gregory Falkovich Weizmann Institute	Physical Nature of Information How much can we do and say about something we do not know? Trying to answer this question quantitatively brought us thermodynamics, statistical mechanics and information theory. I shall present a brief history of these developments, emphasizing the analogies in the limits imposed by uncertainty on engines, measurements, communications and computations. The review is panoramic aiming to show that the people working on quantum computers and the entropy of black holes use the same tools as those designing self-driving cars and market strategies, studying molecular biology, animal behavior and human languages, and figuring out how the brain works. I’ll finish with some recent applications to turbulence as an ultimate far-from-equilibrium state with the lowest entropy.
  October 19	Xiaoxing Xi Temple University	Crackdown on Academic Collaboration with China Harms American Science Academic collaboration with China was once encouraged by the US government and universities. As tension between the two countries rises rapidly, those who did, especially scientists of Chinese descent, are under heightened scrutiny by the federal government. Law enforcement officials consider collaborating with Chinese colleagues “by definition conveying sensitive information to the Chinese.” In 2015, I became a casualty of this campaign despite being innocent. “China Initiative” established by the Justice Department in 2018 has resulted in numerous prosecutions of university professors for alleged failure to disclose China ties. In this talk, I argue that academic decoupling is not in America’s interest. It is a tall order to convince the public and policy makers of this fact, but the scientific community must try lest the American leadership in science and technology will be irreparably damaged.
  November 2	Angela Kelly Stony Brook University	Access and Equity in the Physics Education Pipeline Science, technology, engineering, and mathematics (STEM) careers have traditionally served as mechanisms for socioeconomic advancement in the U.S., yet participation in academic coursework that prepares students for the STEM workforce has not been equitable. Recent calls for reform in physics education have highlighted persistent disparities in access and equity for traditionally underrepresented populations in precollege and university settings. The Institute for STEM Education (I-STEM) at Stony Brook houses the Ph.D. Program in Science Education, where faculty and researchers examine important questions related to STEM educational outcomes. This colloquium will present recent research exploring three main segments of the physics education pipeline: (1) physics educational opportunities, participation, and teacher quality in high school settings; (2) science academic gatekeeping in community colleges; and (3) undergraduate experiences in physics, particularly remote laboratory classes. Findings utilizing a variety of research methodologies will be presented, along with implications for policy and practice in physics education.
  November 9	Sergey Syritsyn Stony Brook University	A more perfect Universe: the role of lattice QCD in constraining fundamental symmetry violations Violations of fundamental symmetries, in particular CP(charge*parity) and baryon number conservation, are immensely important to understanding the origin of matter in the Universe. Evidence for such violations, such as proton decay, neutron-antineutron oscillation, and the neutron electric dipole moment, have not yet been observed despite decades of dedicated experiments. In these searches, the common "probes" are protons and neutrons. Precise knowledge of their structure in terms of their elementary constituents, quarks and gluons, is crucial to connecting experimental bounds to theories incorporating symmetry violations. In my talk, I will review the role, the methods, and the status of Quantum Chromodynamics calculations on a lattice that connects quark-gluon interactions and nucleon structure.
  November 16	Anja von der Linden Stony Brook University	Cosmology with Galaxy Clusters The observed number of galaxy clusters provides a sensitive probe of the structure of the Universe, including dark energy, by measuring the evolution of the halo mass function. However, already current cluster surveys are systematically limited by uncertainties in the relation between cluster mass and observables (e.g. number of galaxies, X-ray luminosity, or the imprint on the Cosmic Microwave Background). I will discuss the challenges in determining mass-observable relations, and how the combination of weak gravitational lensing and X-ray observations can address these. I will review current cluster cosmology results, including those from the "Weighing the Giants" project which placed some of the tightest single-probe constraints on dark energy to date. I will comment on how cluster triaxiality and orientation bias can alleviate the surprisingly low matter density inferred from clusters in the Dark Energy Survey. I will conclude with an outlook towards cluster cosmology with future sky surveys, in particular the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST).
  November 30	Xijie Wang SLAC	Watch water molecules dancing with MeV electrons   Water is one of the most important, yet least understood, liquids in nature. Many strange properties of liquid water, such the highest density at 39 degrees Fahrenheit and high surface tension, originate from its well-connected hydrogen bond network. A complete unveiling of the intermolecular dynamics of water requires direct time- and structure-resolved measurements. It is a challenge to  use X-ray or  neutron scattering to study water’s hydrogen bond structure dynamics due to the lacking in scattering sensitivity (X-ray) or time resolution (neutron).  Recent developments in megaelectronvolt electron ultrafast electron diffraction (MeV-UED) [1-3] made it possible, for the first time, watching water molecule interacts with its neighbors [4] and formation of the short-lived hydroxyl-hydronium pair of the ionized water molecule [5].  Our experiment directly observed the quantum mechanical nature of how the hydrogen atoms are spaced out, and this quantum effect could be the missing link in theoretical models describing strange properties of water. I will also discuss development of MeV-UED - a new paradigm in ultrafast electron scattering.