Colloquium

The colloquium is currently held at 4:30PM on Tuesdays in Harriman 137. Cookies, Tea and Coffee are served from 4:15PM 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 2022 Colloquia

Date	Speaker	Title & Abstract
Feb 1	Navid Vafaei-Najafabadi	Recruiting the 4 ^th 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.

Date

Speaker

Title & Abstract

Feb 1

Navid Vafaei-Najafabadi

Recruiting the 4 ^th 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.

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.

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.

Events and Outreach