Physics and Astronomy Department

Colloquium Series

The Department of Physics and Astronomy hosts weekly seminar talks which are usually scheduled on Thursdays during common hour (12:50 – 1:50 PM) in Room N304 of the Science and Engineering Building, unless otherwise indicated. Lunch is served starting at 12:20PM. All are welcome!

2019 - 2020

2018 - 2019

  • Spring 2019
    Colloquium Schedule

    Thursday April 4, 2019

    1st week of classes: no seminar

    Math, ECBE, Physics and Astronomy joint seminar

     

    Thursday April 11, 2019

    during common hour

    Karp 005

     

    Towards Cyber-Physical Electrical Power Systems: where the laws of nature and the rules of algorithms collide!

    Luigi Vanfretti
    Electrical, Computer, and Systems Engineering, RPI

    Electrical power networks are undergoing unprecedented changes. On one hand, the adoption of distributed energy resources (DER) and renewable energy sources (RES), both of which have a large degree of variability in small time-scales, puts challenges to the traditional, historical-and-experience-based design and operation of electrical power networks. On the other hand, digitization and automation, opens opportunities for a more carbon neutral electrical energy system by helping to harmonize these new energy sources with the rest of the power grid, not without also bringing along the potential threats of the cyber world. This talk aims to give an overview of these challenges, and to present different research efforts conducted by the presenter to address how to transform today’s electrical grid into a cyber-physical power system. This includes the development of an experimental facility to conduct, real-time hardware-in-the-loop simulation experiments of power networks with “cyber” assets. This approach allows to characterize how the interaction of systems governed by the laws of nature will interact with engineered systems governed by rules of algorithms. Finally, with the rise of electrification in transport, and in particular aircraft, and the rise of more autonomous machines, the talk will also discuss the need for development of a new course on modeling and simulation for cyber-physical systems (CPS) and the teaching approach adopted which brings a “digital” toolbox and know-how to the next generation of electrical engineers that will have to increasingly deal with complex CPS.

     

    Please note the new location: Karp 005

    Thursday April 18, 2019 during common hour in S&E N304

    The dark side of the force: searching for dark sector physics

    Andre Sterenberg Frankenthal, Cornell University

    Dark matter is one of the greatest puzzles facing physics today. Our attempts to find a dark matter particle have so far come up empty-handed, and the theoretical models that have guided these efforts for the last 30 years are increasingly suspect. We still have few clues as to its nature. In this talk, I will explore two new and complementary experimental methods to look for evidence of a dark sector which are currently underway. Both methods search for the hypothetical dark photon, a mediator of a fifth force similar to ordinary electromagnetism that could provide the long-sought bridge between ordinary and dark sector physics. I will discuss prospects for the two experiments, experimental challenges, and perspectives for future dark matter-related new physics efforts.

    Thursday May 2, 2019 during common hour in S&E N304

    COMPRES lecture in Geophysics:Core Crystallization and its Impact on Planetary Cooling

    Anne Pommier
    Scripps Institute of Oceanography, UC San Diego

    Core crystallization is a crucial ingredient in the evolution of terrestrial planets and moons and is controlled primarily by chemistry and temperature. Crystallization within a metallic core releases latent heat and gravitational energy, influencing significantly the processes responsible for the presence of a magnetic field. The diversity of magnetic fields observed in small terrestrial bodies, such as the Moon, Mars, Mercury or Ganymede suggests different core cooling history. Past space missions have observed that Mars and the Moon do not currently possess an internally-generated magnetic field but likely had one early in their history, while Mercury currently possesses a weak magnetic field and Ganymede is characterized by a strong one. The origin of this diversity is not well understood and seems to depend highly on the onset, depth, and rate of crystallization. This presentation will focus on the effect of chemistry on core crystallization and its implications for the magnetic field. All results will be compared to the magnetic history and available observational constraints on the core structure, temperature and composition of Mars, the Moon, Mercury and Ganymede.

    Thursday May 16, 2019 during common hour in S&E N304

    Supporting the Advances in Nanoscale Science and Engineering

    Jason E. Sanabia, Ph.D.
    President & CEO, Raith America, Inc.

    My appreciation for teamwork has grown over the years.  In high school and college, I thought I could do physics all by myself as an individual.  Having a good teacher was prerequisite, of course, and even taken for granted.  During graduate school, this individuality started giving way as I worked closely with another generous graduate student.  As a postdoc, I found that individuality would really break down, and I succeeded only because I was part of a positive environment where each postdoc was really helping the other to succeed.  Now I work at Raith.

    Nanoscale problems are just too hard to solve without cooperation between smart and positive people.  Teamwork therefore underlies the significant advances in nanoscale science and engineering.  Much like the teamwork between students, postdocs, professors, universities, and technology companies, there is the cooperation between Raith and our customers.  Raith is committed to enabling the success of our customers, who are advancing quantum physics and computing, photonics, plasmonics, biotechnology, nanoelectronics, 1D and 2D nanomaterials and systems, compound semiconductors, superconducting devices, nanofabrication, x-ray microscopy, electron/ion microscopy, metrology, maskless ion implantation, ion-solid interactions, communications, energy, security and cybersecurity, reverse engineering, and neuroscience.

    The essence of Raith’s contribution towards advancing these fields is to place complex patterns of charged particles at resolutions and accuracies down to the order 100 nanometer over areas spanning 108 nanometers, and do so after the instrument has shipped over a distance of the order 1015 nanometers.  As part of its mission in supporting the advances in nanoscale science and engineering, Raith associates can make these instruments perform to their fullest potential, have a practical understanding of e.g. how thermal expansion coefficients and imperfections in charged particle optical systems can wreak havoc at the nanoscale, and how the same technology that was recently used to detect gravitational waves is practically employed for ultra-accurate sample motion.  Raith is an excellent alternative to a career in academia because we have a similar mission.

    Thursday May 23, 2019 during common hour

    Please note the change in location. This will be in Olin 115.

    Biomechanical Insights Into Flexible Wings From Gliding Mammals

    Gregory Byrnes

    Biology Department, Siena College

    Gliding evolved at least nine times in mammals. Despite the abundance and diversity of gliding mammals, little is known about their convergent morphology and mechanisms of aerodynamic control. Many gliding animals are capable of impressive and agile aerial behaviors and their flight performance depends on the aerodynamic forces resulting from airflow interacting with a flexible, membranous wing (patagium). Although the mechanisms that gliders use to control dynamic flight are poorly understood, the shape of the gliding membrane (e.g., angle of attack, camber) is likely a primary factor governing the control of the interaction between aerodynamic forces and the animal’s body. Data from field studies of gliding behavior, lab experiments examining membrane shape changes during glides and morphological and materials testing data of gliding membranes will be presented that can aid our understanding of the mechanisms gliding mammals use to control their membranous wings and potentially provide insights into the design of man-made flexible wings.

    Thursday May 30, 2019 during common hour in S&E N304

    Fast Neutron Resonance Radiography for Elemental Imaging

    David Russell Perticone
    MIT

    We present experimental evidence supporting the technique of Fast Neutron Resonance Radiography (NRR). A set of neutron attenuation images collected at several different neutron energies are transformed into a set of elemental maps, indicating the presence and quantity of a fixed set of basis elements. Here we report on the construction, calibration, and results from a prototype NRR imaging system. We discuss the utility of elemental maps for automated detection of materials as well as standoff non-destructive classification of chemical compounds. The initial application is explosive detection in air cargo containers.

    Thursday June 6, 2019

    Sigma Pi Sigma Induction: No seminar

     

  • Winter 2019
    Colloquium Schedule

    Thursday January 10, 2019

    Research Opportunities for Students.

    Jef Wagner
    Department of Physics and Astronomy, Union College

    This is an information session. Prof. Wagner will discuss REU opportunities at the Department and outside the department. Members of the department will share their research and announce research opportunities in their team. Notes of the presentation are available through this link.

    Thursday January 24, 2019

    Life After Physics

    Brandon Bartell ’10 (Union College)

    Beyond academia and applied sciences in industry, career options for physicists are varied and non-formulaic. This presentation follows the journey and decision-making of an aspiring academic physicist turned business consultant turned data scientist. The audience should expect to leave with a foundational understanding of consulting as a business model and as a career, data science and its applications in industry, and how a background in physics can prepare individuals for an alternative career beyond the physical sciences.

    Thursday January 31, 2019

    Please note the change in location. This will be in Olin 115.

    Geothermal Heating and Cooling Systems: The Foundation of Zero-Emission Buildings

    John Ciovacco
    President of Aztech Geothermal, LLC

    Geothermal heating and cooling systems (also known as, ground source heat pump systems) will be a significant contributor to society’s conversion away from fossil fuels. Geothermal space conditioning systems heat and cool homes and institutions at extremely high efficiencies by leveraging the constant temperatures found underground. The session will explain how geothermal works, why many institutions are undergoing geothermal conversions to achieve carbon reduction goals, and why New York’s electric utilities are specifically promoting the expansion of geothermal technology.

    Thursday February 7, 2019

    Optical imaging of atomic wave functions with diffraction-breaking resolution

    Yang Wang
    Joint Quantum Institute,University of Maryland

    Optical trapping and imaging of atoms plays an essential role in cold-atom physics, ranging from precision measurement to the study of correlated many body systems. Due to the diffraction limit, trapping and imaging are typically limited to length scales on the order of the wavelength of the light. The nonlinear response of three-level atoms, however, supports a dark state with spatial structures much smaller than the wavelength. In this talk, I will present the experimental use of such dark state spatial structure to probe the atomic wave function with a resolution of lambda/50 (lambda is the wavelength of the imaging light), far below the diffraction limit. The coherent nature of our approach also provides a fast temporal resolution (500 ns), with which we could observe the quantum motion of atoms “live” inside the unit cell of an optical lattice.
    Reference:
    [1] arXiv: 1807.02871
    [2] PRL 120, 083601 (2018)

    Thursday February 14, 2019

    Cosmic Lego: Making molecules on stardust

    Gianfranco Vidali
    Physics Department, Syracuse University

    Where did we come from? This question might not have an answer yet, but, as proposals for a non-terrestrial origin of life have gained some traction, astrophysicists and astrochemists have begun to ask whether there are molecules in space that are complex enough to be used as building blocks of life.
    I always like to show how we learn about the physical world based on observations, experimentation and deduction. In this presentation, I’ll give a brief survey of space environments where molecules have been found and show that key molecules for origin of life do form, and they do on stardust. Then I’ll show how observations, laboratory work and computer simulations can be used to uncover the physical and chemical processes of molecule formation in space, and how they can help guide observations.

    Thursday February 28, 2019

    INNOVATION, INTELLECTUAL PROPERTY & ENTREPRENEURSHIP LAW

    Shahrokh Falati, Ph.D., J.D.
    Director of Programs for Intellectual Property, Tech. Transfer, Innovation & Entrepreneurship Law, Albany Law School

    Bio: Shahrokh (Seve) Falati’s area of legal expertise includes Patent Law; Trademark & Unfair Competition Law; Intellectual Property Law; and the interdisciplinary legal fields governing legal representation of entrepreneurs and innovators (aka Entrepreneurship Law). Prof. Falati is the Director of Programs for Intellectual Property, Technology Transfer & Entrepreneurship Law at Albany Law School. Prior to joining the faculty at Albany Law School, for over a decade, Professor Falati worked in private practice, focusing exclusively on representing clients on Intellectual Property Law and related legal matters at two large prominent law firms in New York (Jones Day, and HRFM). He maintains a small private practice. He is admitted to practice law in New York and Massachusetts, before the United States District Court for the District of Massachusetts, and as a registered patent attorney before the United States Patent & Trademark Office.

    Thursday March 14, 2019

    Revealing Light-Matter Interactions at the Nanoscale using Single-Molecule Super-Resolution Microscopy

    Esther A. Wertz
    Department of Physics, Applied Physics & Astronomy, RPI

    Metal nanoparticles (NPs) sustain a collective oscillation of their free electrons, called a localized surface plasmon resonance (LSPR), when excited by an electromagnetic wave. When this incident wave is resonant with the LSPR frequency, the field intensity is strongly increased in the near field of the NP. Plasmonics thus provides a unique tool for the manipulation and confinement of light well beyond the diffraction limit. This has opened up a wide range of applications based on extreme light concentration, including nanophotonic lasers and amplifiers, optical metamaterials, biochemical sensing, and antennas transmitting and receiving light signals at the nanoscale. However, many difficulties remain in experimentally measuring the shape, size, and enhanced field properties of the localized electromagnetic modes in the vicinity of the NPs due to the limitations of optical microscopy. In this seminar, I will discuss how we can unravel the coupling of light to a nano-antenna through single-molecule fluorescence imaging. This technique is a powerful tool to optically study structures beyond the diffraction limit by localizing isolated fluorophores and fitting the emission profile to the microscope point-spread function. By using the random motion of single dye molecules in solution to stochastically scan the surface, and by assessing emission intensity, wavelength, and density of emitters as a function of position, we gain new insight into the properties of these systems and pave the way for the development of better plasmonic devices.

     

  • Fall 2018
    Colloquium Schedule

    Thursday September 06, 2018

    1st week of classes: no seminar

    Thursday September 13, 2018 during common hour in S&E N304

    Student Poster Presentation

    Department of Physics and Astronomy, Union College

    The department hallways will be decorated by posters by Union College physics majors who participated in summer research this year. The authors will stand by their posters to discuss their work and answer our questions while we all enjoy lunch during our first official colloquium of the new academic year.

    Thursday September 20, 2018 during common hour in S&E N304

    The Physics of the Exposure of Photoresists to Extreme Ultraviolet (EUV, 13.5 nm) Light

    Robert L. Brainard
    Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute

    For the past fifty years, the microelectronics industry has been on a relentless pace to improve the performance of integrated circuits by fabricating more transistors onto every chip. One key technology which has made these dramatic improvements possible has been photoresists (Figure 1A). Central to improving the resolution capability of photoresists has been the successive reduction in the wavelength of light used to expose them. Currently, the microelectronics industry is undergoing a jump in wavelength from 193 to 13.5 nm. This new wavelength is called Extreme Ultraviolet (EUV)) light. This large change in wavelength comes with a concomitant change in photon energy (6.4 to 92 eV) which creates several interesting problems for chemists and physicists to solve. This presentation will start with a broad introduction to photoresists and EUV lithography. It then will describe how 92 eV EUV photons ionize molecules in resists, creating holes and free electrons, and identify and discuss the individual interactions that occur with atoms (Figure 1B). However, the number of electrons created, their reaction mechanisms, their lifetimes and their reaction cross-sections are not well known. The presentation will discuss experimental results and provide insight into these poorly understood aspects of EUV exposure mechanisms (Figure 1C). Lastly, the presentation will discuss the challenges associated with the low numbers of high-energy photons that are available during exposure relative to the longer wavelength 193-nm lithography that proceeded EUV. These low numbers of photons create statistical-noise problems described as shot-noise and related to Poisson statistics. These statistics ultimately place a limit to the ultimate resolution, line-roughness, and sensitivity of this imaging technology.

    Introduction of manufacture of integrated circuits using photoresists

    Joint Seminar with Chemistry and Mechanical Engineering

    Thursday October 4, 2018 during common hour: Location Olin 115

    X-ray Optics Development at NASA Marshall Space Flight Center

    David Broadway
    Research Physicist, NASA MSFC, Huntsville, AL

    The path toward the development of X-ray optics for the next generation of high resolution, large collecting area space-borne telescopes is discussed. A leading technological challenge associated with this development is due to the intrinsic stress in the nanometer-scale thin film coatings that are deposited to enhance the reflective performance of the optics. The coating stress causes severe distortion of the thin (~400 µm), precisely figured substrates and degrades the imaging resolution of the optics. Therefore, a novel optical method for the in-situ measurement of thin film stress has been developed to help identify process mechanisms for reducing or eliminating film stress. The device utilizes a fiber optic displacement sensor (FODS) to measure the evolving substrate curvature during the deposition process. The measured substrate curvature is proportional to the integrated film stress as described by the Stoney equation. The minimum detectable integrated stress of the device is presented and compared to other state-of-the-art optical methods of in-situ stress measurement. The reproducibility and sensitivity of the apparatus is demonstrated through stress measurements of tungsten (W) and amorphous silicon (Si) single and multilayer thin-films deposited on 100µm thick Schott D263 glass substrates by the process of magnetron sputtering. Additionally the use of silica aerogels produced by Union College’s rapid supercritical extraction technique as a potential method for replicating unprecedented ultra-lightweight mirrors from precision optical quality molds is discussed.

    Thursday October 11, 2018 during common hour in S&E N304

    The Physics of Wetting and Spreading at the Nanoscale

    Mesfin Tsige
    Department of Polymer Science, University of Akron, Akron, Ohio, USA

    There is a tremendous need for a greater understanding of the properties of matter at the nanometer scale mainly driven by the unprecedented impact of nanoscale materials in current industrial products. It is well known that matter behaves in complex ways and exhibits exotic properties at nanometer length scales. However, understanding the behavior of matter at such length scales using experimental methods has in general been very difficult. Computer simulations have proven very useful in predicting properties of novel materials yet to be synthesized as well as predicting difficult to measure or poorly understood properties of existing materials. The most commonly used computational technique for investigating structural and dynamical properties of nanoscale materials is molecular dynamics simulations. I will discuss the physics embedded in this computational tool and its use for simulating soft materials behavior at the atomic scale. Specifically, I will talk about my group’s current effort in quantifying the dynamics of hydrogen bonding and its effect on the spreading behavior of nanoscale water droplets on polymer surfaces using molecular dynamics simulations. Hydrogen bonding is very critical to a wide range of systems, from the existence of liquid water at room temperature to the structure of DNA (double helix) and many other biomolecules. Understanding the strength and dynamics of hydrogen bonds has stimulated a large and growing body of experimental and theoretical work. However, despite much research progress made over the years on this topic, our understanding of the dynamics of hydrogen bonds, especially at surfaces and interfaces, is still work in progress.

    Thursday October 18, 2018 during common hour in S&E N304

    Lattices, Supersymmetry and Strings

    Joel Giedt
    Department of Physics, Applied Physics & Astronomy, RPI

    In this talk I will explain why lattice discretizations of spacetime can help us to study challenging theories like supersymmetric gauge theories numerically. Some aspects of the high-end computing platforms that we use will also be discussed. Questions about quantum gravity and remarkable dualities can be addressed using techniques that were first developed to study the strong nuclear interaction. I will finish the talk by describing how string compactifications may be used to describe models of dark matter that is self-interacting, and may also provide tools to understand interactions with the Standard Model.

    Thursday November 1, 2018 during common hour in S&E N304

    Liquid-liquid phase separation in concentrated protein mixtures, with application to cataract

    George Thurston
    School of Physics and Astronomy, RIT

    Liquid-liquid phase separation, the solution analogue of the liquid-vapor transition, has long been demonstrated to occur in aqueous solutions and in membranes of biological molecules. Recently, there has been a rapid pace of discoveries of liquid-liquid phase separation that are important in physiology and disease. We will introduce liquid-liquid phase separation for a general audience, and will describe our own studies of its occurrence in concentrated aqueous mixtures of eye lens proteins, which are important in cataract disease. We will then describe our ongoing studies of how charge regulation affects liquid­-liquid phase separation of the eye lens protein gamma crystallin. For gamma crystallin, our grand­-canonical distribution model indicates that hundreds of coexisting, equilibrium charging patterns have enough probability to affect protein interactions. We describe a theoretical framework for studying the resulting, simultaneous liquid-liquid phase separation and multiple chemical equilibrium, which resembles the situation that occurs in micellar and microemulsion solutions. Supported by NIH R15EY018249.

    Thursday November 8, 2018 during common hour in S&E N304

    Research Opportunities for Students.

    Jef Wagner
    Department of Physics and Astronomy, Union College

    This is an information session. Prof. Wagner will discuss REU opportunities at the Department and outside the department. Members of the department will share their research and announce research opportunities in their team. Notes of the presentation are available through this link.

     

2017-2018

  • Spring 2018

    Thursday April 5, 2018

    1st week of classes: no seminar

    Thursday April 12, 2018 during common hour in S&E N304

    The Fate of Exploding White Dwarfs

    Robert Fisher
    Department of Physics, University of Massachusetts Dartmouth

    Type Ia supernovae play an important role as standardizable candles for cosmology, providing one of the most important probes into the nature of dark energy. Yet, the nature of the stellar progenitors which give rise to Type Ia supernovae remains elusive. For decades, the leading model explaining Type Ia supernovae properties consisted of a white dwarf accreting to near the Chandrasekhar mass, in the single-degenerate channel. More recently, a variety of lines of evidence point instead towards merging binary white dwarfs in the double-degenerate channel as the progenitors of most Type Ia supernovae. In this talk, I will focus upon recent advances at the interface between observation and theory which will help crack the Type Ia progenitor problem.

    Thursday April 19, 2018

    No Seminar

    Thursday April 26, 2018 during common hour in S&E N304

    A Gamified Approach to Online Astronomy Education

    Danny Barringer
    Union College ‘11, M.S./M.Ed. Penn State

    Online education is the way of the future! Or so we keep hearing. As schools race to increase their online course offerings, scholarship on innovative ways to use this new educational space is relatively lacking. I will be talking about the state of the online education field broadly, including an overview of the role that games can fill in educational settings. I present on some work I've done evaluating student performance in an online, gamified version of introductory astronomy taught at Penn State since 2014, and how the most gamified aspects contribute (or not) to student learning. I close with my own thoughts about how we can most effectively use these new educational platforms and what challenges still need to be properly addressed.

    Thursday May 3, 2018 during common hour in S&E N304

    Why Physics?

    Hal Tugal
    BS Physics Union College ’71, MS Physics UNH ’73; PhD Engineering UNH ’77

    After spending childhood in Europe and growing up in NY (Brooklyn, NY, then Ardsley, NY in Westchester Country), Hal Tugal realized that no matter how much he liked arts, he was better suited for physics. He attended Union College in Schenectady, NY, went to the University of New Hampshire to earn MS in physics (Space Science), and finally a PhD in Theoretical and Applied Mechanics in the Mechanical Engineering Department. He spent over 30 years in industry applying classical physics to solve problems in the power, metal and glass containers, defense, aerospace and semiconductor industries. His brief talk today will be on, Why physics?

    Thursday May 10, 2018

    Steinmetz week: No seminar

    Thursday May 17, 2018 during common hour in S&E N304

    A Modeling Study of Low-Level-Jets over the Mid-Atlantic Region

    Mengsteab H. Weldegaber
    Department of Physics & Astronomy, Howard University

    A modeling study of the Low-Level-Jets over the mid-Atlantic region is presented. The Low-Level-Jets were observed during the Water Vapor Validation Experiments (WAVES), a NASA Satellite validation experiment, at Howard University Beltsville research Campus in summer 2006/07. The objective of this research is to understand the dynamics and the strength the winds during the observed Low-Level-Jets over Baltimore-Washington area; and also to test and evaluate the Weather Research and Forecasting (WRF) model. The observed high-resolution wind profiles from Maryland Department of Environment; radio soundings and lidar observations at Beltsville; and lidar observations at University of Maryland Baltimore County are used to validate the simulated wind and moisture profiles. Sensitivity simulations using different boundary layer schemes in WRF model with the Advanced Research WRF (ARW) dynamic core will be discussed.

    Thursday May 24, 2018 during common hour in S&E N304

    Determining Stellar Properties using Asteroseismology

    Lucas Viani ‘14
    Yale Center for Astronomy and Astrophysics, Yale University

    Asteroseismology, the study of stars using stellar oscillations and pulsations, allows astronomers to derive stellar properties such as mass, radius, and age more accurately and precisely than ever before. Additionally, unlike with isochrone fitting, stellar properties can be determined without the need for distance or extinction estimates. The basic asteroseismic parameters provide valuable information about a star’s interior and can be determined even in poor signal-to-noise observations, making them readily available for a large number of stars. Here we show how asteroseismology can be used to determine stellar properties and examine the accuracy and pitfalls of such methods. Additionally, we use Kepler data to improve how convection is modeled in star.

    Thursday May 31, 2018 during common hour in S&E N304

    The Modern Alchemy of Converting Office Supplies into Smart Materials

    Kevin Cavicchi
    Department of Polymer Engineering, University of Akron

    Shape-morphing materials are one class of smart materials that adjust their shape in response to an external stimuli. These materials find application as sensors and for remote manipulation of materials in industries ranging from aerospace to biomedical to consumer products. This talk will discuss two types of shape morphing polymers: shape memory polymers (SMPs) and actuators. In an SMP a range of elastic deformation is temporarily locked into place through a programming sequence of heating, deformation, and cooling and triggered to return to its initial shape upon the application of an external stimulus. Actuators, on the other hand are able to oscillate between two shapes in response to an environmental trigger (e.g. heat, humidity). This talk will describe facile methods to fabricate these materials by blending commercial elastomers and waxes. This compounding approach allows each component to synergistically contribute separate functions to the shape morphing materials, which simplifies the design of the individual components and opens up the ability to fine-tune the shape morphing properties through the blend formulation. Two examples will be presented where first, the wax forms a solid networks to gel the surrounding elastomer and fix elastic deformation, and second, the melting and expansion of the wax dilates the surrounding elastomer to actuate the shape.

    Thursday June 7, 2018

    Sigma Pi Sigma Induction: No seminar

  • Winter 2017

    Thursday January 05, 2017

    Summer research opportunities

    we will provide information to students about research opportunities at Union and outside Union.

     

    Thursday February 9, 2017 -- Moved to April 27 due to Weather

    A Career in Big Data: Physics and the Software Industry

    Jason Slaunwhite '04

    During this talk I will share a few short stories from my career in Big Data. After graduating from Union in 2004, I did research in High Energy Particle Physics and went on work at the CERN laboratory in Switzerland. I have continued to work with Big Data as a software developer for an analytic database company. I hope that by sharing a few of my experiences with current physics majors, I can provide some perspective on the different opportunities that they may consider pursuing after graduation.

    Thursday February 16, 2017

    Synchronization in Networks of Biomimetic Artificial Neurons

    Harold M Hastings
    Division of Science, Bard College at Simon’s Rock, and Department of Physics and Astronomy, Hofstra University

    There has been a long tradition of the study of model neurons, beginning with pioneering work of Hodgkin and Huxley. Subsequently FitzHugh, Nagumo and colleagues developed a simplified two variable conductance model for neuronal dynamics, consisting membrane potential whose (fast) dynamics reflect a non-linear sodium current and a (slow) gate variable (potassium current). FitzHugh-Nagumo neurons can display either excitable (sufficiently large stimuli generate action potentials before returning to steady state) or oscillatory dynamics, depending upon parameter values. We explore the dynamics networks of FitzHugh-Nagumo neurons and analogues, especially Keener’s modification of the original Nagumo circuit and the Belousov-Zhabotinsky chemical reaction, the prototype chemical oscillatory system. A wide variety of complex synchronization and emergent behavior is seen. There are potential applications to computer science, biology, and biomedicine.

    Selected References:

    • Alford, S.T., Alpert, M.H., A synaptic mechanism for network synchrony. Frontiers Cellular Neuroscience 8, doi.org/10.3389/fncel.2014.00290 (2014)
    • Arumugam, E.M.E., Spano, M.L., A chimeric path to neuronal synchronization. Chaos 25, 013107 (2015)
    • Belair, J., et al., Dynamical disease: identification, temporal aspects and treatment strategies of human illness. Chaos 5, 1 (1995)
    • Beuter, A., Bélair, J., Labrie, C., Feedback and delays in neurological diseases: a modeling study using dynamical systems. Bull. Math. Biol. 55, 525 (1993).
    • FitzHugh, R., Impulses and physiological states in theoretical models of nerve membrane. Biophys. J. 1, 445 (1961).
    • Hastings, H.M., Field, R.J., Sobel, S.G., Microscopic fluctuations and pattern formation in a supercritical oscillatory chemical system. The Journal of chemical physics, 119, 3291 (2003).
    • Hastings, H.M., et al., Bromide control, bifurcation and activation in the Belousov− Zhabotinsky Reaction. J. Phys. Chem. A 112, 4715-4718 (2008).
    • Hastings, H.M. et al., Oregonator Scaling Motivated by Showalter-Noyes Limit. J. Phys. Chem. A 120, 8006 (2016).
    • Hastings, H.M. et al., Dynamics of Biomimetic Electronic Artificial Neural Networks, Proceedings of the 4th International Conference on Applications in Nonlinear Dynamics (ICAND 2016), Ed: V. In, P. Longhini, A. Palacios, Springer (in press, to appear in 2017).
    • Keener, J.P., Analog circuitry for the van der Pol and FitzHugh-Nagumo equations. IEEE Trans. Systems Man Cybernetics 5, 1010 (1983).
    • Nagumo, J., Arimoto, S., Yoshizawa, S., An active pulse transmission line simulating nerve axon. Proc. IRE 50, 2061 (1962).
    • Tompkins, N., et al., Creation and perturbation of planar networks of chemical oscillators. Chaos 25, 064611 (2015).
    • Tuma, T., et al., Stochastic phase-change neurons. Nature Nanotech. 11, 693 2016).

    Thursday February 23, 2017

    Founders Day

    Thursday March 2, 2017

    Craig Luckfield
    PASCO scientific

    Thursday March 9, 2017

    Synthesis of Device-Quality Graphene Films

    Carl A. Ventrice, Jr.
    Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY

    Graphene is a single atomic layer of carbon that is crystallized in the honeycomb configuration. It has many unique properties that are of particular interest for the development of nanoscale electronic devices and sensors. In particular, it is a semi-metal whose charge carrier density can be continuously tuned from n-type to p-type by applying an external electric field and has a linear energy-momentum dispersion in the vicinity of the Dirac point, which results in carrier mobilities that are higher than almost all semiconductors. It also has a very large in-plane thermal conductivity and exceptional mechanical properties. However, one of the primary issues that must be addressed before nanoscale electronic devices and sensors can be routinely fabricated is the development of methods for growing large-scale, device-quality, graphene films with uniform thickness at a relatively low cost. An overview will be given of the techniques currently used for graphene synthesis and the research being done in my laboratory to synthesize single crystal films of graphene.

  • Fall 2017

    Thursday September 07, 2017
    1st week of classes: no talk scheduled

    Thursday September 14, 2017

    Effects of Supplementary Information on Solution Methods to Kinematics Problems

    Evan Halstead
    Physics Department, Skidmore College

    A student once told me that the formula sheets I provided for tests always made her want to immediately jump to the formula sheet for every problem instead of thinking about it first. That got me wondering whether I was inadvertently influencing all of my students' solution methods with subtle cues. To answer this question, a team of students and I devised an experiment in which participants solved three kinematics questions while having access to either relevant equations, irrelevant equations, an image, or no supplementary information at all. They were then asked to describe their solution process. Answers were grouped by solution method in order to see if the type of supplementary information that was provided correlated with the solution method. I present and comment on the results.

    Thursday September 21, 2017

    Summer Student Poster Day

    The department hallways will be decorated by posters by Union College physics majors who participated in summer research this year. The authors will stand by their posters to discuss their work and answer our questions while we all enjoy lunch during our first official colloquium of the new academic year.

    Thursday September 28, 2017

    Signal Processing Using Chaos

    Chandra Pappu
    Electrical, Computer and Biomedical Engineering, Union College

    A new, rich class of oscillators namely chaotic oscillators with nonlinear behavior have tremendous potentials in the field of signal processing. Due to its self-synchronizing capabilities these oscillators can be used in network synchronization, receiver-transmitter synchronization etc. In addition, chaotic waveforms generated by chaotic systems are noise like and wideband in nature. The potentials of these chaotic systems are illustrated considering few examples. Firstly, I illustrate the application of chaos for secret communications. Secondly, I show the advantages of using chaotic frequency modulated signals in jamming/interference environment. Finally, I demonstrate the high resolution capability of chaotic waveform considering BOEING 777 airplane.

    Please note the change in location. This seminar will be in Lippman 017.

    Thursday October 05, 2017

    A Classical, Magnetic, Many-Body System
    or
    Adventures in Desk Toy Physics

    Nelia Mann
    Department of Physics & Astronomy, Union College

    ®Buckyballs are small, strong, spherical magnets sold in sets as popular desk toys. Each separate magnet can be well modeled as a magnetic dipole, and thus interactions between pairs of magnets are easily understood in terms of classical electrodynamics. In larger numbers, the magnets form structures that can be thought of as analogous to structures of atoms or molecules within bulk materials. In this talk, I will utilize some of the traditional tools of solid state physics along with numerical techniques to analyze this “toy system”. The results suggest that insight into real solid state systems might be gained through comparison to this system.

    Thursday October 12, 2017

    Superconducting qubits for quantum processors

    Daniela Bogorin
    National Research Council Fellow, Air Force Research Laboratory

    In the last two decades remarkable advances have been made in quantum information processing. There are many technologies that are being developed for the physical realization of a quantum bit (qubit), each with its own advantages and disadvantages. These technologies include optical photons, trapped ions, superconducting qubits, neutral atoms, molecules, quantum dots, nuclear spins, and NV centers in diamond among others. Superconducting qubits based on Josephson Junctions superconducting circuits is one of the leading technologies. Progress in the development of superconducting qubits in the last five years demonstrates a viable path towards quantum processors with tens of qubits, required for proving quantum supremacy and ultimately towards a fault tolerant quantum computer. Superconducting qubits have high coherences ~ 100 μs and are manipulated by fast gates ~ few ns and are fabricated using semiconductor technology. In this talk I will present a short overview of the field and an introduction of superconducting qubit technology.

    Thursday October 19, 2017

    Confining colloids: From dynamic artificial cells to luminescent nanodiamond sensors

    Viva Horowitz
    Department of Physics, Hamilton College

    Watching nano- and microscale particles in confined environments can reveal new physics, whether we create a dynamic system that mimics cellular motion or use the quantum spin of nanodiamonds to explore a magnetic environment. In the first part of this talk, we’ll explore the possibilities of using self-propelled particles to create a super-diffusive system that beats Brownian motion, much like the interior of cells. We’ll discuss how to investigate the motion of these particles using holography and other optical techniques, and see how these particles can be encapsulated in lipid vesicles or in droplets. The dynamics and transport processes of this artificial cytoplasm may prove necessary to sustain gene expression, growth, and reproduction in future artificial cells. In the second part, we’ll explore how nitrogen-vacancy color centers embedded in nanoparticle diamonds have electronic quantum spin states that are sensitive to magnetic fields via electron spin resonance. When we pick up these nanodiamond probes using optical tweezers, we can measure and map the magnetic environment despite the motion and random orientation of nanodiamonds levitated by the laser beam. However, challenges remain: these spin states are sensitive to impurities in the diamond crystal and surroundings. We need to find the best diamond particles for spin-based magnetic, electric, and thermal sensing in fluidic environments and biophysical systems. Toward this end, we are building a microfluidic device to sort nanodiamonds according to their optical properties.

    Please note the change in location. This seminar will be in N300.

    Thursday October 26, 2017

    Nucleation in Undercooled Metal Droplets –Applications in the Microelectronics Industry

    Eric Cotts
    Physics and Materials Science, Binghamton University

    Most of the metallic materials that we use in daily life are prepared by casting from the melt. We seek to understand and control the physics of such solidification processes. Classical nucleation theory reflects the essence of the nucleation and initial growth of crystals from an undercooled melt. It works best for systems with simpler bonding mechanisms, such as Lennard-Jones and many transition metals. For more complex systems, such as Sn, metastable precursors form first from the melt at nanometer length scales. These metastable inoculants can affect the entire structure of solids, and their properties (for instance in microelectronic interconnects). We explore the nucleation of undercooled Sn droplets as a function of impurity concentration, and examine effects on the microstructure, and properties, of interconnects in electronic packages.

    Thursday November 02, 2017

    Physics in Radiation Oncology

    Tom Mazur (class of 2007)

    Applications of physics pervade medicine. “Medical Physics” refers to careers in radiology and radiation oncology that provide support for the safe and effective delivery of radiation to cancer patients for both diagnostics and therapy. A conventional career trajectory for a medical physicist begins with a post-graduate degree in Medical Physics that covers a specialized curriculum tailored to a career in a clinical setting. Many clinics, especially in academic settings, increasingly value candidates with non-conventional backgrounds in basic sciences like physics. After graduating from Union College, I attended graduate school in the physics department at The University of Texas at Austin where I studied atomic physics. After graduate school, I was a post-doctoral researcher in the radiation oncology department at the Washington University School of Medicine in St. Louis. I now am a researcher and clinical trainee in the same department. In this talk I will describe careers in medical physics, including necessary pre-requisites and training, day-to-day responsibilities, various technologies, and opportunities for research.

    Thursday November 09, 2017 No: seminar

    The Department is hosting the NYSSAPS and ASNY joint Fall meeting on Gravitational Waves on November 10 and 11. For more information and registration, visit www.nyssaps.org.

    Congratulations Prof Rainer Weiss on Winning the 2017 Nobel Prize in Physics!

2016 - 2017

  • Spring 2017

    Thursday March 30, 2017

    Fractals and the Drip Paintings of Jackson Pollock

    Katherine Brown (Jones-Smith)
    Physics Department, Hamilton College

    In the late 1990s, a group of physicists analyzed some of the most famous drip paintings by the celebrated Abstract Expressionist painter Jackson Pollock. Assuming Pollock underwent a particular type of chaotic motion, they found that every layer of every painting they analyzed possessed the same fractal characteristics. From this they conjectured that Pollock was able to create a unique fractal 'signature' in his work, and that fractal analysis could therefore be used as an authentication tool in paintings of disputed origin. It turns out that this hypothesis of 'Fractal Expressionism' is flawed in several important ways. I will present an account of the techniques used in fractal analysis and the pitfalls which ensue from applying them to Pollock's drip paintings. I will also discuss several new findings from the realm of fractal mathematics which were motivated by this work.

    Thursday April 6, 2017

    Excitons in Small Molecules Crystalline Thin Films

    Madalina Furis
    Physics Department, University of Vermont

    Organic electronics, an interdisciplinary research area traditionally more connected to organic synthetic chemistry and polymer science than condensed matter physics, is currently undergoing a major transformation. The advent of high mobility small molecule semiconductors and new avenues for scalable thin film and device fabrication introduce a new paradigm in the way we think about the future of electronics.

    At the University of Vermont my research group focuses on exploring crystalline organic semiconducting thin films using condensed matter experimental approaches (such as low temperature, polarization-resolved, ultrafast spectroscopy) on a quest for signatures of many-body physics in these systems. Recent results include: i) the observation of a low temperature coherent exciton state [1] ii) the surprising discovery of excitonic states localized at the grain boundary that may provide new insight on exciton diffusion in these systems,[2]

    1. Rawat, N., et al. J.Phys. Chem. Lett. 2015, 6(10), 1834-1840.
    2. Pan, Z., et al. Nat.Commun. 2015, 6.

    Email Contact: Madalina.Furis@uvm.edu

    Thursday April 13, 2017

    Topology of the Universe: Hearing the Shape of a drum

    Eric Greenwood
    Geology and Physics Department, University of Southern Indiana

    Observationally, we know that the universe is locally flat. This does not tell us, however, the overall shape of the universe; that is, it does not tell us anything about the global shape of the universe (topology). There are many different global shapes which yield the same local shape. The question of the structure and size of the universe is both an intellectually interesting and an important question in modern cosmology since the answer to these questions could give us insight into the ultimate fate of our universe. Additionally, knowledge of the shape and size of the universe will give us information about the metric of the universe, which has many implications such as implications toward quantum gravity. In this talk, we will investigate how to reconstruct the topology of the universe using the spectrum of eigen modes dictated by a particular topology; that is, we will investigate how to "hear the shape of a drum."

    Thursday April 20, 2017

    The God Quasiparticle: the Plasmon and Protein Spectroscopy

    Shyamsunder Erramilli
    Department of Physics, Boston University

    How do we get an infrared vibrational spectrum of a protein molecule at attomole concentrations at room temperature? The absorption cross-section of the molecule is ~ 10-21 cm2, about 6 orders of magnitude smaller than methods based on fluorescent labels. To enhance the probability of absorption, we can exploit the very first quantum quasi-particle that was ever discovered, the plasmon. Nanoantenna can be used to enhance selected vibrational bands. Recently a collaboration with Dal Negro has used fractal structures for enhancing multiple infrared absorption band in the mid-infrared “fingerprint” region. The interaction between the phonon in the protein and the plasmon leads to extraordinary new phenomena. Plasmon-enhanced infrared spectroscopy has the potential to study changes in protein conformation without using labels, with discoveries of great interest to the Biological Physics community as well as the Biomedical community.

    Thursday April 27, 2017

    A Career in Big Data: Physics and the Software Industry

    Jason Slaunwhite '04

    During this talk I will share a few short stories from my career in Big Data. After graduating from Union in 2004, I did research in High Energy Particle Physics and went on work at the CERN laboratory in Switzerland. I have continued to work with Big Data as a software developer for an analytic database company. I hope that by sharing a few of my experiences with current physics majors, I can provide some perspective on the different opportunities that they may consider pursuing after graduation.

    Thursday May 4, 2017

     

     

    Thursday May 11, 2017

    Steinmetz Symposium Week

    Thursday May 18, 2017

    Searching for the Sources of the Highest-Energy Cosmic Neutrinos

    Colin Turley
    Department of Physics, Penn State

    We present two archival analyses attempting to identify gamma-ray counterparts to the public neutrino data from the IceCube neutrino observatory. Our first analysis is a targeted search for correlated neutrino and gamma-ray emission from six bright northern blazars. These blazars were subject to long-term monitoring campaigns by the VERITAS TeV gamma-ray observatory. We use the publicly-available VERITAS light-curves to identify periods of excess and flaring emission to serve as active temporal windows in a search for an excess of neutrinos, relative to Poisson fluctuations of the near-isotropic atmospheric neutrino background. Our second analysis searches for an excess of statistically significant coincidences between Ice-Cube neutrinos from the 40 and 59 string configurations and gamma-rays detected by the Fermi LAT satellite. Both analyses are examples of more general multi-messenger studies that the Astrophysical Multi-messenger Observatory Network (AMON) aims to perform. For both analyses, we present the component neutrino and gamma-ray datasets, the statistical approaches, the results of the analyses, and future extensions to these studies.

    Thursday May 25, 2017

    Optics and electronics in two-dimensional (2D) materials

    Swastik Kar
    Department of Physics, Northeastern University

    In the past decade, atomically-thin, layered or 2D materials have generated enormous interest within the science and engineering community. The unique nature of charge carriers, often experiencing strong interactions within a 2D confinement has led to spectacular new physical observations. At the same time, remarkable new applications have been shown to be possible within these materials with atomically-thin form-factors. This talk will outline some of the recent developments in our research group in the synthesis of 2D materials and their heterostructures, characterizations of their novel optical and electronic properties, and development of applications in the nanoelectronics, optoelectronics, sensing, detection, actuation, energy, and other areas. The aim will be to motivate how the novel physics of quantum matter can be potentially harnessed to develop applications with unprecedented performances.

    Thursday June 1, 2017

    Sigma Pi Sigma Induction

  • Winter 2017

    Thursday January 05, 2017

    Summer research opportunities

    we will provide information to students about research opportunities at Union and outside Union.

    Thursday February 9, 2017 -- Moved to April 27 due to Weather

    A Career in Big Data: Physics and the Software Industry

    Jason Slaunwhite '04

    During this talk I will share a few short stories from my career in Big Data. After graduating from Union in 2004, I did research in High Energy Particle Physics and went on work at the CERN laboratory in Switzerland. I have continued to work with Big Data as a software developer for an analytic database company. I hope that by sharing a few of my experiences with current physics majors, I can provide some perspective on the different opportunities that they may consider pursuing after graduation.

    Thursday February 16, 2017

    Synchronization in Networks of Biomimetic Artificial Neurons

    Harold M Hastings
    Division of Science, Bard College at Simon’s Rock, and Department of Physics and Astronomy, Hofstra University

    There has been a long tradition of the study of model neurons, beginning with pioneering work of Hodgkin and Huxley. Subsequently FitzHugh, Nagumo and colleagues developed a simplified two variable conductance model for neuronal dynamics, consisting membrane potential whose (fast) dynamics reflect a non-linear sodium current and a (slow) gate variable (potassium current). FitzHugh-Nagumo neurons can display either excitable (sufficiently large stimuli generate action potentials before returning to steady state) or oscillatory dynamics, depending upon parameter values. We explore the dynamics networks of FitzHugh-Nagumo neurons and analogues, especially Keener’s modification of the original Nagumo circuit and the Belousov-Zhabotinsky chemical reaction, the prototype chemical oscillatory system. A wide variety of complex synchronization and emergent behavior is seen. There are potential applications to computer science, biology, and biomedicine.

    Selected References:

    • Alford, S.T., Alpert, M.H., A synaptic mechanism for network synchrony. Frontiers Cellular Neuroscience 8, doi.org/10.3389/fncel.2014.00290 (2014)
    • Arumugam, E.M.E., Spano, M.L., A chimeric path to neuronal synchronization. Chaos 25, 013107 (2015)
    • Belair, J., et al., Dynamical disease: identification, temporal aspects and treatment strategies of human illness. Chaos 5, 1 (1995)
    • Beuter, A., Bélair, J., Labrie, C., Feedback and delays in neurological diseases: a modeling study using dynamical systems. Bull. Math. Biol. 55, 525 (1993).
    • FitzHugh, R., Impulses and physiological states in theoretical models of nerve membrane. Biophys. J. 1, 445 (1961).
    • Hastings, H.M., Field, R.J., Sobel, S.G., Microscopic fluctuations and pattern formation in a supercritical oscillatory chemical system. The Journal of chemical physics, 119, 3291 (2003).
    • Hastings, H.M., et al., Bromide control, bifurcation and activation in the Belousov− Zhabotinsky Reaction. J. Phys. Chem. A 112, 4715-4718 (2008).
    • Hastings, H.M. et al., Oregonator Scaling Motivated by Showalter-Noyes Limit. J. Phys. Chem. A 120, 8006 (2016).
    • Hastings, H.M. et al., Dynamics of Biomimetic Electronic Artificial Neural Networks, Proceedings of the 4th International Conference on Applications in Nonlinear Dynamics (ICAND 2016), Ed: V. In, P. Longhini, A. Palacios, Springer (in press, to appear in 2017).
    • Keener, J.P., Analog circuitry for the van der Pol and FitzHugh-Nagumo equations. IEEE Trans. Systems Man Cybernetics 5, 1010 (1983).
    • Nagumo, J., Arimoto, S., Yoshizawa, S., An active pulse transmission line simulating nerve axon. Proc. IRE 50, 2061 (1962).
    • Tompkins, N., et al., Creation and perturbation of planar networks of chemical oscillators. Chaos 25, 064611 (2015).
    • Tuma, T., et al., Stochastic phase-change neurons. Nature Nanotech. 11, 693 2016).

    Thursday February 23, 2017

    Founders Day

    Thursday March 2, 2017

    Craig Luckfield
    PASCO scientific

    Thursday March 9, 2017

    Synthesis of Device-Quality Graphene Films

    Carl A. Ventrice, Jr.
    Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY

    Graphene is a single atomic layer of carbon that is crystallized in the honeycomb configuration. It has many unique properties that are of particular interest for the development of nanoscale electronic devices and sensors. In particular, it is a semi-metal whose charge carrier density can be continuously tuned from n-type to p-type by applying an external electric field and has a linear energy-momentum dispersion in the vicinity of the Dirac point, which results in carrier mobilities that are higher than almost all semiconductors. It also has a very large in-plane thermal conductivity and exceptional mechanical properties. However, one of the primary issues that must be addressed before nanoscale electronic devices and sensors can be routinely fabricated is the development of methods for growing large-scale, device-quality, graphene films with uniform thickness at a relatively low cost. An overview will be given of the techniques currently used for graphene synthesis and the research being done in my laboratory to synthesize single crystal films of graphene.

  • Fall 2016

    Thursday September 08, 2016
    1st week of classes : No talk scheduled

    Thursday September 15, 2016

    Summer Student Poster Day

    The department hallways will be decorated by posters by Union College physics majors who participated in summer research this year. The authors will stand by their posters to discuss their work and answer our questions while we all enjoy lunch during our first official colloquium of the new academic year.

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    Thursday September 22, 2016

    Few-Layer Black Phosphorus: a Material with tunable properties

    Vincent Meunier
    Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute

    Black phosphorus (or “phosphorene” at the monolayer limit) has attracted significant attention as an emerging 2D material due to its unique properties compared with well-studied graphene and transition metal dichalcogenides such as MoS2 and WSe2. In bulk form, this monoelemental layered structure is a highly anisotropic semiconductor with a bandgap of 0.3 eV which presents marked differences in optical and electronic properties depending on crystalline directions. In addition, black phosphorus possesses high carrier mobility, making it promising for applications in high frequency electronics. A large number of characterization studies have been performed to understand the intrinsic properties of BP. Here I will present a number of investigations where first-principles modeling was combined with scanning tunneling microscopy (STM), Raman spectroscopy, and transmission electron microscopy (TEM) to assist in the design of phosphorene-based devices.

    Thursday September 29, 2016

    Dark matter: All your questions answered...with more questions!

    Matthew Bellis
    Department of Physics and Astronomy, Siena College

    Over the last 50+ years, we have definitively learned that the motions of galaxies and clusters and the curvature of light on cosmological scales cannot be explained solely by the gravitational attraction of the baryonic matter in the universe. The leading theory to explain this discrepancy proposes a particle that does not interact through the strong or electromagnetic interaction: dark matter. However, no definitive experimental evidence for this particle has been found. This talk will give an introductory overview of the experimental searches for dark matter with an emphasis on WIMP (Weakly Interacting Massive Particle) models.

    Wednesday October 05, 2016

    Amorphous Materials:  From Two-Dimensional Glass to Bubble Rafts

    Kristen M. Burson
    Physics Department, Hamilton College

    Glass is a pervasive material in daily life, from windows, to fiber optics, to kitchen ware.   Due to the abundant utility of glass there is much interest in answering the question: “What is the atomic structure of glass?” For crystalline materials, diffraction techniques can be used to determine the atomic configuration. But glass evades definitive atomic structure determination with the same techniques because it is complex and amorphous. SiO2 in its amorphous form is commonly known as glass for every-day uses. In this talk I’ll discuss recent work to determine the atomic structure of glass using scanning probe microscopy. I’ll show atomic resolution images of bilayer silica (SiO2), a model for glass, and present an assessment of the structure of model glass under application relevant conditions. Finally, this talk will explore the similarities between glass and other amorphous networks with special emphasis on a comparison between millimeter-scale bubble raft network structures and the atomic-scale silica network structure.

    Thursday October 13, 2016

    Mechanics of Fibrous Materials

    Catalin R. Picu
    Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute

    Many biological and man-made materials have a fiber network as their structural component. Examples from the living world include the cellular cytoskeleton and various types of connective tissue. Examples from the non-living world include paper, rubber, insulation and consumer products, such as baby diapers. In this presentation I will review the mechanical behavior of various materials of this type. Further, the relationship between the microstructure and the mechanical properties of the network will be outlined, with emphasis on identifying regimes in which large changes of the system scale behavior are triggered by small changes of the system parameters. The discussion will underline differences between the behavior of fibrous materials and that of continuum bodies.

    Thursday October 20, 2016

    Phyllosilicate Emission from Protoplanetary Disks – The Indirect Detection of Extrasolar Water

    Melissa Morris
    Physics Department, SUNY Cortland

    Phyllosilicates are hydrous minerals formed by the interaction between rock and liquid water and are commonly found in meteorites originating in the asteroid belt. These products of aqueous alteration of primitive planetesimals are believed to be the source of the majority of Earth’s water. The spectrum of the zodiacal dust in our Solar System (thought to result from collisions of planetesimals and sublimation of comets) has been modeled with the inclusion of phyllosilicates. Collisions between planetesimals in extrasolar protoplanetary disks may also produce dust containing phyllosilicates, indicating the presence of liquid water. It has been demonstrated that the characteristic emission features of these hydrous minerals are detectable in the infrared using instruments on board the Spitzer Space Telescope. In this talk, I discuss the phyllosilicates commonly found in meteorites, and describe our simple 2-layer radiative transfer disk code used to produce model spectral energy distributions (SEDs) of disks. I discuss how archived data from the Spitzer Space Telescope can be used to compare model SEDs of protoplanetary disks to observations. In this manner, we can determine whether liquid water is indicated in these extrasolar systems, and therefore, the possibility for life.

    Thursday October 27, 2016

    Explorations in the Geometry of Thinking

    Kurt Przybilla
    The Molecularium Project, Rensselaer Polytechnic Institute

    Model building inspired by the works of  Buckmister Fuller, the visionary inventor of geodesic domes and namesake of "Bucky Balls",  led to the accidental discovery and patenting of the world's first spinning tops with more than one axis of spin.  Co-creator, writer and producer of the Molecularium Project at RPI, Kurt Przybilla, shares a fast-paced, fun story of tetrahedrons, toys and the primary structural systems of the Universe.

    Thursday November 03, 2016

    String Theory in the Age of Duality

    Cindy Keeler
    Neils Bohr Institute

    After a brief review of string theory and its genesis as a “Theory of Everything”, we will discuss the nature and use of dualities in modern string theory and quantum gravity. Dualities provide two (often very different!) descriptions of the same physical system.  We will study an example of duality in Maxwell's equations, and then explore how these dualities have led to broad applications of string-inspired physics, far beyond its initial high energy physics beginnings.

    Thursday November 10, 2016

    From Ultracold Plasmas to White Dwarf Stars

    Thomas C. Killian
    Department of Physics & Astronomy, Rice University, Houston, TX 77005

    Some of the most extreme environments in the universe can be described as strongly coupled plasmas, which are characterized by an average Coulomb interaction energy between neighboring particles that exceeds the thermal kinetic energy. This is the case in dense laboratory and astrophysical plasmas, such as in inertial-confinement-fusion experiments, white dwarf stars, and gas-giant-planet interiors. Strong interactions limit our ability to model and understand these systems because they violate fundamental assumptions underlying the standard theoretical description of collision rates and transport coefficients. They also lead to spatial correlations and surprising equilibration dynamics. I will describe how we can study the physics of strongly coupled plasmas in a system created by photoionizing laser-cooled atoms [1]. This creates the coldest neutral plasmas in existence, with temperatures barely one degree above absolute zero. Strong coupling is obtained at relatively low density, which slows the dynamics and makes short-timescale processes (compared to the inverse collision rate) experimentally accessible. This combination of atomic and plasma physics opens a new direction in the study of “dense” plasmas, which has traditionally been the playground of astrophysics and large national facilities. In particular, I will describe recent experiments studying the breakdown of standard kinetic theory and the measurement of self-diffusion [2,3].

    This work is supported by the National Science Foundation, Department of Energy, and the Air Force Office of Scientific Research.

    [1] “Ultracold Neutral Plasmas,” T. C. Killian and S. L Rolston, Phys. Today 63, 46 (2010).
    [2] “Velocity relaxation in a strongly coupled plasma,” G. Bannasch, J. Castro, P. McQuillen, T. Pohl and T. C. Killian, Phys. Rev. Lett. 109, 185008 (2012).
    [3] “Experimental measurement of non-Markovian dynamics and self-diffusion in a strongly coupled plasma,” T. S. Strickler, T. K. Langin, P. McQuillen, J. Daligault, and T. C. Killian, arXiv.org/1512.02288 (2015).