Department of Physics and Astronomy

University of Mississippi

Events

  • Tue
    24
    Jan
    2017
    4:00 pmLewis Hall 101

    Hartmut Grote
    Division of Laser Interferometry and Gravitational Wave Astronomy
    Albert Einstein Institute — Hannover, Germany

    The Physics of Climate, the IPCC, and the Public Discourse:
    A Tour D'Horizon of Global Warming

    Global warming is a topic of broad scientific inquiry as well as societal relevance. I will review the basic principles of climate physics, explain the role of the IPCC in assessing different aspects of global warming, and will try to shed some light on the public discourse around global warming and forces trying to obstruct the science.

  • Tue
    24
    Jan
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Randy M. Wadkins
    Department of Chemistry and Biochemistry
    University of Mississippi

    It’s a Small World After All
    Nanomaterials are types of matter that lie in size between single molecules and bacteria, or approximately one millionth of a millimeter. Where do you find such tiny little objects? Right in plain sight! Maybe you were hungry today and grabbed a slice of American Cheese or a tub of Greek yogurt from the fridge. Maybe afterward you brushed your teeth with toothpaste, or freshened your breath with gum. Maybe you took a shower and used a dandruff shampoo, then put on deodorant. Maybe you then put on stain-resistant pants, dabbed on a little sunscreen, and headed off to campus. All of those items I just mentioned contain nanoparticles, so small you can’t see each one, but essential for product performance.

    In this follow-up to my 2016 TEDxUM talk, I will describe what the nanoparticles do in these products, then talk a little about nanoengineering using DNA, with a particular focus on the future of nanomedicine. Like in the movie “Fantastic Voyage,” nanomedicine is close to being reality.
    See this page for details.

  • Sun
    05
    Feb
    2017
    6:30 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • February 5, Sunday, 6:30 - 9:00 PM

    We plan to observe  the Moon,  nebulae  and  star  clusters though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!
    Due to the buses we have moved from Friday to Sunday nights.
    See this page for the full schedule.

  • Tue
    07
    Feb
    2017
    4:00 pmLewis Hall 101

    Mauricio Richartz
    Centro de Matemática
    Universidade Federal do ABC — Brazil

    Analogue Black Holes: Theory and Experiments

    Analogue models of gravity, introduced by Unruh in 1981, have been (for some time now) very helpful towards a better theoretical understanding of several crucial phenomena at the boundary of gravity and quantum field theory. Experimental research on analogue models, however, started only very recently. In this talk, I will explain the basic theory behind analogue models of gravity and how they can be used to mimic important quantum field theory effects in curved spacetimes, like Hawking radiation. I will also focus on some experimental realizations of analogue models of gravity, including one based on surface waves propagating on water. which I have been involved with very recently (arXiv: 1612.06180).

  • Tue
    14
    Feb
    2017
    4:00 pmLewis Hall 101

    Graduate Students
    Department of Physics and Astronomy
    University of Mississippi

    Temperature Dependent Behavior of Shear Waves in a Micellar Fluid (Sunethra Dayavansha)
    Development of Brain Tissue-Mimicking Phantom (Somayeh Taghizadehghahremanloo)
    Negative Refraction and Super-resolution by a Steel-methanol Phononic Crystal (Ukesh Koju)
    Development of a Tilt-free Seismometer (Reza Afrough)
    The RKKY Interaction for Link Variables on the Square Lattice (Huu Do)
    Experimental Test of an Omnidirectional Acoustic Enhancement Method (Maryam Landi)
    Deforming the Fredkin Spin Chain Away from its Frustration-free point (Khagen Adhikari)

  • Tue
    21
    Feb
    2017
    4:00 pmLewis Hall 101

    Maarten Buijsman
    Division of Marine Science
    University of Southern Mississippi

    The Equatorial Pacific "Graveyard" for Semidiurnal Internal Tides: Incoherence or Dissipation?

    The jets in the equatorial Pacific Ocean of a realistically-forced global circulation model with a horizontal resolution of 1/12.5 degree yield a strong loss of phase coherence in semidiurnal internal tides that propagate equatorward from the French Polynesian Islands and Hawaii. This loss of coherence is determined with a baroclinic energy analysis, in which the semidiurnal-band terms are separated into coherent, incoherent, and cross terms. For time scales longer than a year the coherent energy flux approaches zero values at the equator, while the total flux is 500 W/m. The time-variability of the incoherent energy flux is compared with phase speed variability computed with the Taylor-Goldstein equations. The variability of monthly-mean Taylor-Goldstein phase speeds agrees well with the phase speed variability inferred from steric sea surface height phases extracted with a plane-wave fit technique. On monthly time scales, the loss of phase coherence in the equatorward beams from the French Polynesian Islands is attributed to the time variability in the sheared background flow associated with the jets and tropical instability waves. On an annual time scale, the effect of stratification variability is of equal or greater importance than the background flow is to the loss of coherence. The model simulation suggests that low-frequency jets do not noticeably enhance the dissipation of the internal tide, but merely decohere and scatter it. Thus, the apparent demise of coherent internal tides seen in satellite altimetry maps of the equatorial Pacific may be due to incoherence rather than dissipation.

  • Tue
    21
    Feb
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Susan Pedigo and Lemuel Tsang
    Department of Chemistry and Biochemistry
    University of Mississippi

    Chemistry of Milk

     

    Why is some cheese stringy and other cheese crumbly? We will discuss this topic and others as we tour the chemistry of the proteins, lipids and carbohydrates in milk. Through the millennia, human cultures have exploited one biomolecule or another to create a wide range of foods from milk. We will cover a diverse range of topics including the incredible origin of milk, butter and its close cousin margarine and the art of cheese making.

    See this page for details.

  • Mon
    27
    Feb
    2017
    Thu
    02
    Mar
    2017
    9:00 a.m. - 5:00 p.m.Yerby Conference Center, University of Mississippi

    The “Strong Gravity and Binary Dynamics with Gravitational Wave Observations” workshop convenes Feb. 27 to March 2 in the Yerby Conference Center. The event is supported in part by Emanuele Berti’s National Science Foundation CAREER Award and by a Marie Sklodowska-Curie Research and Innovation Staff Exchange Action network, funded by the European Union’s FP7 program.

    “This network supports exchanges of gravity researchers among the participating nodes,” said Berti, associate professor of physics and astronomy. “In addition to Ole Miss, there are five nodes in Europe, one in in Japan and one in Canada. A dozen researchers will visit campus for a month before and after the workshop.”

    About 50 scientists representing some 30 research agencies and institutions of higher learning are scheduled to attend. Researchers will discuss several topics in the newborn field of gravitational-wave astronomy, including the astrophysics of compact binary populations, spin measurements in compact binaries, strong-field tests of Einstein’s theory of general relativity and how to look for hints of new gravitational physics beyond Einstein’s theory.

    For more about the workshop, visit http://www.phy.olemiss.edu/StronGBaD/. For more about the Department of Physics and Astronomy, go to http://physics.olemiss.edu/.

    Also see the article from Inside Ole Miss.

  • Fri
    03
    Mar
    2017
    4:00 pmLewis Hall 101

    Carlos Herdeiro
    Departamento de Física
    Universidade de Aveiro — Portugal

    Can a Black Hole Have Hair?

    Black holes are one of the most fascinanting predictions of Einstein's theory of General Relativity. In their most paradigmatic guise, they are also the simplest objects in the Universe, made solely of space and time. Moreover, powerful mathematical theorems, known as uniqueness theorems, show that the way space and time can curve into a black hole is quite restricted, and these objects are only described by two parameters: their total mass and angular momentum. John Wheeler famously coined this simplicity into the mantra "Black Holes have no hair". But underlying this statement there is an unproved belief known as the "no-hair conjecture".

    I will start by discussing observational evidence for the existence of black holes in the universe. Then, I will explain why the existence of some simple types of matter, even if Einstein's theory holds, could challenge the no-hair conjecture and produce "hairy" black holes. Finally, I will discuss how ongoing and forthcoming electromagnetic and gravitational waves observations could test the existence of black hole "hair" of this sort.

  • Tue
    07
    Mar
    2017
    4:00 pmLewis Hall 101

    Seth Hopper
    Gravitation in Técnico
    Instituto Superior Técnico — Portugal

    Bound and Unbound Motion Around Static Black Holes

    A massive two-body system will interact gravitationally. Depending on the velocities and separation of bodies, their motion may be bound and periodic (as in the Earth-Sun system) or unbound (like a comet that passes the Sun only once). General relativity predicts that each of these systems will radiate energy in the form of gravitational waves. However, the qualitative difference between the systems implies that different techniques must be used to analyze them. In this talk I will briefly introduce the mathematical theory behind gravitational radiation of two body systems (specifically in the extreme mass-ratio regime) and consider how one can efficiently compute that radiation for different classes of problems.

     

    Andrea Nerozzi
    Gravitation in Técnico
    Instituto Superior Técnico — Portugal

    The Problem of Gauge Fixing in the Newman-Penrose Formalism

    Since its introduction the Newman-Penrose formalism has been widely used in analytical and numerical studies of Einstein's equations, like for example for the Teukolsky master equation, or as a powerful tool for wave extraction in numerical relativity. The problem of gauge fixing, or more specifically, tetrad fixing is however still debated and only partially understood when the NP formalism is used to extract gravitational waves from numerical simulations.

    In this talk I will approach the whole formalism with the goal of finding an invariant expression for all the variables in the NP formalism, namely Weyl scalars and the spin coefficients, once a specific yet generally defined tetrad is chosen.I will show that it is possible to do so, and give a general recipe for the task, as well as an indication of the quantities and identities that are required. The applications and importance of this approach to the problem of wave extraction in numerical relativity will be discussed.

    Laura Bernard
    Gravitation in Técnico
    Instituto Superior Técnico — Portugal

    Dynamics of Compact Binary Systems at the Fourth Post-Newtonian Order

    Templates of coalescing compact binaries' gravitational waveform are used for the detection and precise determination of the physical parameters of gravitational waves by the current and next generations of interferometric detectors. In order to compute the waveform with high accuracy, the dynamics of compact binary systems should be known to the same precision. In this talk, I will address the question of the dynamics of non-spinning compact binary systems at the fourth post-Newtonian order in harmonic coordinates. I will present a method based on a Fokker action adapted to the specificities of the post-Newtonian formalism, including the so-called tail effects which appear for the first time in the conservative dynamics at 4PN. I will then derive the energy and periastron advance for circular orbits and show a full agreement with previous results from gravitational self-force calculations.

  • Tue
    21
    Mar
    2017
    4:00 pmLewis 101

    Sabrina Savage
    Science Research Office
    Marshall Space Flight Center

    Reconnecting with Solar Flares

    Because the Earth resides in the atmosphere of our nearest stellar neighbor, events occurring on the Sun's surface directly affect us by interfering with satellite operations and communications, astronaut safety, and in extreme circumstances, power grid stability. Solar flares, the most energetic events in our solar system, are a substantial source of hazardous space weather affecting our increasingly technology-dependent society. While flares have been observed using ground-based telescopes for over 150 years, modern space-bourne observatories have provided nearly continuous multi-wavelength flare coverage that cannot be obtained from the ground. We can now probe the origins and evolution of flares by tracking particle acceleration, changes in ionized plasma, and the reorganization of magnetic fields. I will walk through our current understanding of why flares occur, show several examples of these fantastic explosions, and describe the technology and instrumentation being developed at Marshall Space Flight Center to observe these phenomena.

  • Tue
    21
    Mar
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Sabrina Savage
    Science Research Office
    Marshall Space Flight Center

    Reconnecting with Solar Flares

    Because the Earth resides in the atmosphere of our nearest stellar neighbor, events occurring on the Sun's surface directly affect us by interfering with satellite operations and communications, astronaut safety, and in extreme circumstances, power grid stability. Solar flares, the most energetic events in our solar system, are a substantial source of hazardous space weather affecting our increasingly technology- dependent society. While flares have been observed using ground- based telescopes for over 150 years, modern space-bourne observatories have provided nearly continuous multi-wavelength flare coverage that cannot be obtained from the ground. We can now probe the origins and evolution of flares by tracking particle acceleration, changes in ionized plasma, and the reorganization of magnetic fields. I will walk through our current understanding of why flares occur, show several examples of these fantastic explosions, and describe the technology and instrumentation being developed at Marshall Space Flight Center to observe these phenomena.

    See this page for details.

  • Tue
    28
    Mar
    2017
    4:00 pmLewis 101

    Ulrich Sperhake
    Theoretical Astrophysics
    California Institute of Technology

    Searching for Smoking Gun Effects of Modified Gravity in Supernova Core Collapse

    Even though Einstein's theory of general relativity has been an incredibly successful theory and passed a plethora of tests ranging from light bending to the recent detection of gravitational waves, there are indications from theory, astrophysics and cosmology that modifications to the theory may ultimately be required. One of the most popular modifications applied to general relativity is the addition of a scalar field as an extra channel to mediate gravity. Through the introduction of additional degrees of freedom such scalar-tensor theories may explain some of the potentially troublesome phenomena in gravity while preserving compatibility with solar system and other tests. In this talk we explore the dynamics and gravitational wave emission of supernova core collapse in scalar tensor theory for the case of spherical symmetry. We analyse the resulting waveforms and explore under which conditions they may provide smoking gun signals detectable with present and future gravitational-wave detectors.

  • Tue
    04
    Apr
    2017
    4:00 pmLewis 101

    Michael Allshouse
    Department of Mechanical and Industrial Engineering
    Northeastern University

    Internal Wave Breaking and Boluses

    The shoaling of internal waves on a continental slope results in wave steepening and breaking that produces boluses, which are trapped regions of fluid that travel up the slope with the wave. Unlike a propagating solitary wave, these boluses transport material with the wave containing oxygen depleted water and induce rapid changes in temperature both of which have potential ramifications for marine biology. The dramatic difference between the fluid inside the bolus relative to the exterior may also impact local acoustic measurements of the sea floor. We extend a number of two-layer studies by investigating bolus generation and material transport in continuously stratified fluids. Laboratory experiments are conducted in a 4 m long tank and are complemented by 2-dimensional numerical simulations. The boundaries of the bolus are identified using a Lagrangian based coherent structure method relying on trajectory clustering. We use the structure identification to measure the properties of the bolus as a function of the pycnocline thickness and slope angle.

  • Sun
    09
    Apr
    2017
    8:15 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • April 9, Sunday, 8:15 - 10:30 PM

    We plan to observe  the Moon,  nebulae  and  star  clusters though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!
    Due to the buses we have moved from Friday to Sunday nights.
    See this page for the full schedule.

  • Tue
    11
    Apr
    2017
    4:00 pmLewis 101

    Wanwei Wu
    Department of Physics and Astronomy
    University of Mississippi

    The Muon g-2 Experiment at Fermilab

    The muon anomalous magnetic moment (g-2) has played an important role in constraining physics beyond the Standard Model for many years. The Fermilab Muon g-2 Experiment has a goal to measure it to unprecedented precision: 0.14 ppm, which will have a fourfold improvement compared to the BNL g-2 Experiment (0.54 ppm) as well as provide one of the most sensitive tests of the completeness of the Standard Model by comparing with the theory. The Fermilab g-2 Experiment is close to the end of installation and ready for the commissioning and physical running soon. In this talk, I will give an overview of the experiment and discuss the work involved by the OleMiss group.

  • Tue
    11
    Apr
    2017
    6:00 pmLusa Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Susana Martinez-Conde,
    Laboratory of Integrative Neuroscience,
    State University of New York — Downstate Medical Center

    Vision is All About Change

    Your eyes are the sharks of the human body: they never stop moving. In the past minute alone, your eyes made as many as 240 quick movements called “saccades” (French for “jolts”). A portion of our eye movements we do consciously, and are at least aware of on some level. But most of these tiny back-and-forths and ups-and-downs are unconscious and nearly imperceptible; someone staring directly at your eyes would miss most of them. Scientists long believed that we use two types of oculomotor behavior to sample the visual world, alternating between big saccades to scan our surroundings and tiny ones to fix our gaze on a location of interest. Explore, fixate, repeat, all day, every day. It seemed to make intuitive sense that we would have one brain system for exploring the environment and another for focusing on specific objects. But it turns out that exploration and gaze-fixation are not all that different processes in the brain. Instead, our eyes scan visual scenes with a same general strategy, whether the images are huge or tiny, or even when we try to fix our gaze. This insight may offer clues to understanding normal oculomotor function in the healthy brain, and oculomotor dysfunction in neurological disease.

    See this page for details.

  • Tue
    18
    Apr
    2017
    4:00 pmLewis 101

    Tanaz A. Mohayai
    Department of Physics
    Illinois Institute of Technology

    Measurements Of Beam Cooling In Muon Ionization Cooling Experiment

    The international Muon Ionization Cooling Experiment, MICE, is a high energy physics experiment located at Rutherford Appleton Laboratory in the U.K., and its aim is to demonstrate muon beam cooling for the first time. When muons are produced from pion decay, they occupy a large volume in the position-momentum phase space and the process of reducing their volume is known as beam cooling. Several beam cooling techniques exist, but the ionization cooling is the only technique fast enough to be used for muons within their short lifetime. Ionization cooling occurs when the beam loses momentum through energy loss, while traversing a material. In MICE, commonly used figures of merit for cooling are the beam emittance reduction, the phase-space volume reduction, and the phase-space density increase. Emittance is the measure of the size of the beam, and with a reduced beam emittance or phase-space volume, more muons can fit in a smaller aperture of a cost-effective accelerator. This may enable the construction of a future high-intensity muon accelerators, such as a Neutrino Factory or a Muon Collider. To demonstrate beam cooling, MICE makes use of two scintillating-fiber tracking detectors, immersed in the constant magnetic fields of the Spectrometer Solenoid modules. These trackers, one upstream and one downstream of the absorber reconstruct and measure the position and momentum coordinates of individual muons, and the absorber provides the ionization energy loss required for beam cooling. The choice of absorber material is dependent on the achievable energy loss, and the aim is to maximize beam cooling through energy loss while minimizing beam heating from multiple Coulomb scattering. In addition, given the precision with which MICE aims to demonstrate beam cooling, it is necessary to develop analysis tools that can work around any effects which may lead to inaccurate cooling measurements. Non-linear effects in beam optics is one example of such effects and it can result in apparent emittance growth or beam heating. The Kernel Density Estimation, KDE technique is an analysis tool which is insensitive to these non-linear effects and measures the muon beam phase-space density and volume. This talk will give an overview of the recent MICE results, the emittance measurement technique in the recent MICE data, and the novel application of the KDE technique in MICE.

  • Sat
    22
    Apr
    2017
    10:30 amUniversity Circle

    Join us for a celebration of science. Walk from Campus to Oxford square on April 22 to champion and support science.

    Science protects the health of our communities, the safety of our families, the education of our children, the foundation of our economy and jobs, and the future we all want to live in and preserve for coming generations. Science is a tool of discovery that allows us to constantly expand and revise our knowledge of the universe. In doing so, science serves the interests of all humans. Science education teaches children and adults to think critically, ask questions, and evaluate truth based on the weight of evidence. Science promotes diversity and inclusion in science to build robust and resilient communities for the benefit of all people. Science makes our democracy stronger.

    On April 22, scientists and supporters of science will march in cities and towns across the world to reaffirm these core values.

    Please stand up for science and join your fellow Ole Miss scientists in a celebration of science by walking from campus to Oxford square. This is a strictly non-political, non-partisan event. We value inclusion, diversity, equity, and access to everybody. We aim for a diverse group of participants, including first-time marchers. Families with young children are welcome.

    We will assembly on the steps of the Lyceum (University Circle) at 10:30 am and start walking at 11:00am. The planned route (about 1 mile) will take us through the Grove, University Avenue and South Lamar. We will end the march at Oxford Square.

    Please show your support for science as a vital feature of a working democracy, spurring innovation, critical thinking, increased understanding, and better, healthier lives for all people. Follow us on Twitter and Facebook (event).

  • Tue
    25
    Apr
    2017
    4:00 pmLewis 101

    Guido Mueller
    Department of Physics
    University of Florida

    TBA

  • Tue
    02
    May
    2017
    4:00 pmLewis Hall

    Bevin Etienne
    McIntire School of Commerce
    University of Virginia

    The Role of Microgrids and Community Choice Aggregation in Building a Sustainable and Resilient Energy System

    Energy plays a role in every facet of our lives - from food production to clothing and shelter, to the water we drink and the air we breathe and by great extent our ability to do the work we enjoy. With that being said, the energy sector, globally, is plagued with many challenges. For example, the electric grid and most of the energy infrastructure in the US was constructed in the 1950s and 1960s with a 50-year life expectancy1 which signifies the US is due for an overhauling of the system. This does not account for the fact that the energy system of the 1950s and 1960s was not engineered to meet today's energy demands and capability to withstand severe weather related events – in 2012, Super storm Sandy demonstrated our energy system vulnerability to severe weather. All of this suggests that the time is at hand for significant investment in maintaining, upgrading and rebuilding the electric energy infrastructure. Recently conducted research suggests that the replacement value of the U.S. electric grid is $4.8 trillion2.

    This discussion will focus on the use of Microgrids and Community Choice Aggregation (CCA) in addressing the impending energy crisis and assess the social, economic and environmental benefits of employing such an approach to tackling the current energy challenge. Beyond the US, microgrids and CCA offer the opportunity for developing nations to leapfrog the centralized energy infrastructure and provide a more sustainable
    and secure energy system for the 21st century.


    1The American Society of Civil Engineers (ASCE) 2017 Infrastructure Report Card
    2Tsvetana Paraskova, OilPrice.com

  • Tue
    09
    May
    2017
    11:15 amLewis Hall 101

    The 2017 induction ceremony for the National Physics Honors Society, ΣΠΣ will take place on May 9 at 11:15 AM in room 101 in Lewis Hall.

  • Fri
    30
    Jun
    2017
    8:30 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • June 30, Friday, 8:30 - 10:00 PM

    We plan to observe  the Moon, Jupiter and Saturn. though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!

    See this page for the full schedule.

  • Mon
    17
    Jul
    2017
    Thu
    20
    Jul
    2017
    9:00 amRoom 109 Lewis Hall

    The 3rd Annual Belle II Summer School will be held at the University of Mississippi — Monday July 17, 2017 until Thursday July 20, 2017.

    Agenda Topics include:
    Computing, Analysis setup, KLM particle ID, TOP particle ID
    Nanobeams, Vertexing, BASF2, Early physics, BEAST, Reconstruction Code
    Drift Chamber, ARICH particle ID, Event Display

    The Registration will start in room 104 of Lewis Hall at 8:30 AM Monday morning. The meeting will start in room 109 of Lewis Hall at 9:00 AM Monday morning. Lectures will be in room 109 Lewis Hall and the Breakout rooms will be in rooms 109 and 228 Lewis Hall.

    Please see http://www.phy.olemiss.edu/b2ss2017/ for details

  • Fri
    28
    Jul
    2017
    8:30 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • July 28, Friday, 8:30 - 10:00 PM

    We plan to observe  the Moon, Jupiter and Saturn. though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!

    See this page for the full schedule.

  • Mon
    21
    Aug
    2017
    12:00 pmQuad between Lewis Hall, the Library and the Lyceum

    On Aug. 21, Monday, a total solar eclipse swipes through the U.S., a once-in-a-lifetime event. It is best viewed in a narrow band that crosses Nashville, TN.

    It can be seen in Oxford, MS, as a partial solar eclipse, which is still a rare occurrence. While not a total eclipse the Sun will be over 90% covered so it will still be quite impressive. The Department of Physics and Astronomy will organize a viewing 12:00 noon - 3:00 PM. The maximum coverage is at 1:24 PM.

    The viewing is free, all are welcome. (In case clouds cover the Sun, there will be nothing to see.)

    Note: Never look into the eclipsed Sun without a proper solar filter, it is dangerous!!

     

  • Tue
    29
    Aug
    2017
    4:00 pmLewis Hall 101

    Mike Reep and Scott Watkins
    Department of Physics and Astronomy
    University of Mississippi

    Machine Shop Physics

    Experimental physics depends on instrumentation made in the University of Mississippi's Physics machine shop. Instruments made for Acoustics,
    Atmospheric physics, Condensed Matter physics, and Particle physics will be shown.

  • Tue
    05
    Sep
    2017
    4:00 pmLewis 101

    Vahid Naderyan
    Department of Physics and Astronomy
    University of Mississippi

    MEMS Microphones

    MEMS (Micro-Electro-Mechanical Systems) microphones are acoustic sensors which translate sound waves to an electrical signal. Recent developments in MEMS technology have led to the development of very small size and high-performance microphones. Silicon fabrication creates the MEMS elements with the geometries of the order of microns. Due to their small size and high performance, MEMS microphones are used in mobile phones, hearing aids, “Internet of Things” devices, small electronic devices, etc. In this talk, I will explain the basic principles of the capacitive MEMS microphones and will talk about the Acoustical, Mechanical, and Electrical domains in a MEMS microphone and their connections.

  • Tue
    19
    Sep
    2017
    4:00 pmLewis 101

    Ron Miles
    Department of Mechanical Engineering
    State University New York — Binghamton

    The Nanophone: Sensing Sound with Nanoscale Spider Silk

    Hundreds of millions of years of evolution resulted in hair-based flow sensors in terrestrial arthropods that stand out among the most sensitive biological sensors known. These tiny sensory hairs can move with a velocity close to that of the surrounding air at frequencies near their mechanical resonance, in spite of the low viscosity and low density of air. No man-made technology to date demonstrates comparable efficiency. Here we show that nanodimensional spider silk captures fluctuating airflow with maximum physical efficiency (Vsilk/Vair ≈1) from 1Hz to 50kHz, providing an unparalleled means for miniaturized flow sensing. Our mathematical model shows excellent agreement with experimental results for silk with various diameters: 500nm, 1.6µm, 3µm. When a fiber is sufficiently thin, it can move with the medium flow perfectly due to the domination of forces applied to it by the medium over those associated with its mechanical properties. By modifying a spider silk to be conductive and transducing its motion using electromagnetic induction, we demonstrate a miniature, directional, broadband, passive, low cost approach to detect airflow with full fidelity over a frequency bandwidth that easily spans the full range of human hearing, as well as other mammals, birds, amphibians, and reptiles.

  • Tue
    19
    Sep
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Ronald Miles
    Department of Mechanical Engineering
    State University New York — Binghamton

    Biomimetic Acoustic Sensors for Hearing Aids

    Current hearing aids typically use a pair of miniature microphones in order to achieve directional acoustic sensing. Better hearing aids can be designed by examining how the hearing organs of very small animals such as insects and spiders enable these creatures to detect and localize sound. We have studied the hearing in mosquitoes, flies, crickets, midges, caterpillars, and spiders to explore remarkable ways these animals sense sound. This talk will describe our discovery of the amazing directional ears of a special fly, Ormia ochracea, which is able to localize sound better than humans can even though its ears fit in a space only 1 mm across. Our biomimetic microphones based on this discovery show better performance than existing hearing aid microphones. We have also recently discovered new ways to sense sound based on the use of nanoscale fibers such as insect hairs or spider silk. This has resulted in a directional microphone that has ideal flat frequency response from 1 Hz to 50 kHz, far beyond the range of human hearing. There remains much more to learn from nature to create technology to improve hearing.

    See this page for details.

  • Tue
    26
    Sep
    2017
    4:00 pmLewis 101

    Farhad Farzbod
    Department of Mechanical Engineering
    University of Mississippi

    Vibrations: from Periodic Structures to the Human Face

    This talk covers four different and yet connected subjects; Resonant Ultrasound Spectroscopy (RUS), vibration analysis of periodic structures,
    and using facial vibrations in wearable computers. RUS is a technique to characterize the elastic and anelastic properties of materials. It is based on the measurements of the vibration eigenmodes of a sample with simple geometry such as a parallelepiped. In Laser RUS, the excitation part is done by a pulsed laser, generating thermoelastically excited ultrasonic pulse. In the detection side, a photorefractive interferometer is used to detect ultrasound. Measured eigenmodes along with eigenfrequencies reveal much information with regard to micro-structural state of the sample material. Novel techniques/problems in laser RUS is discussed in this section. In the second part, periodic structures are discussed. In periodic lattice structures, analysis of wave propagation to uncover dispersion relationships can be greatly simplified by invoking the Floquet-Bloch theorem. The accompanying Bloch formalism, which was first introduced for the study of quantum mechanics and has been borrowed in structural analysis, allows a system's degrees of freedom to be reduced to a small subset contained in a single unit cell. When this is combined with the finite element method, the result is a powerful framework for analyzing wave propagation and dispersion in complex media. In this section, among other things, the manner in which damping affects dispersion is talked about. In the next part, I talk about reciprocity in acoustics and how to break it; one way to break time reversal symmetry is to have a moving wave propagation medium. If the acoustic wave vector and the moving fluid velocity are collinear, we can use the wave vector shift caused by the fluid flow to break reciprocity. An alternative approach we have taken, is to use a fluid velocity field which enters the differential equation of the system as a cross product term with the wave vector. In the final part, bone conduction hearing is discussed; how it helps hearing and how it can be utilized for better communications in wearable technologies.

  • Sun
    01
    Oct
    2017
    7:00 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • October 1, 2017  7:00 - 9:00 PM

    We plan to observe  the Moon and Saturn. though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!

    See this page for the full schedule.

  • Tue
    03
    Oct
    2017
    4:00 pmLewis 101

    John Thompson
    Department of Physics and Astronomy
    University of Maine

    Investigating Student Understanding at the Physics-Mathematics Interface

    Because learning physics concepts often requires the ability to construct, interpret, and manipulate mathematical representations and formalism
    (e.g., equations, graphs, and diagrams), researchers in physics education and mathematics education have been examining how students navigate
    this interface between mathematics and physics. Our own research into student conceptual understanding of physics has led us to investigate how
    students use and reason about mathematics, especially calculus, to solve physics problems in several upper-division physics domains. Examples
    coming from thermal and statistical physics as well as from vector calculus as used in electromagnetism will be given. Instructional materials
    development and implementation will be discussed.

  • Tue
    10
    Oct
    2017
    4:00 pmLewis 101

    Alex Yakovlev
    Department of Electrical Engineering
    University of Mississippi

    Recent Developments on Graphene and Graphene Periodic Surfaces at Microwave and Terahertz Frequencies

    Graphene, the first 2D material to be practically realized, has attracted great interest in the last decade. The fact that electrons in graphene behave as massless Dirac fermions leads to a variety of anomalous properties, such as charge carriers with ultra-high-mobility and long mean-free paths. Graphene's electrical properties are often represented by a local complex surface conductivity given by the Kubo formula. Since its surface conductivity leads to attractive surface plasmon properties, graphene has become a good candidate for plasmonic applications, especially in the terahertz regime.

    In this talk we will briefly discuss electrical, thermal, and mechanical properties of graphene, and will focus on the interaction of electromagnetic waves with graphene and graphene periodic surfaces at microwave and terahertz frequencies. Specifically, we will discuss the enhanced transmission with a graphene-dielectric stack, dual capacitive/inductive nature of graphene periodic surfaces, high-impedance surfaces with graphene patches, excitation of surface plasmon polaritons on graphene, planar hyperlens based on a modulated graphene, subwavelength imaging with graphene loaded wire media, and cloaking with graphene for antenna applications.

  • Tue
    17
    Oct
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Carolyn Freiwald,
    Department of Sociology and Anthropology,
    University of Mississippi

    This is Your Life in a Tooth

    You might be surprised to learn that a single tooth contains a record of your life... from the types of food that you ate, to where you lived, to how healthy you were as a child. Vegetarians and BBQ lovers have different chemical markers, and so do people with jobs such as blacksmiths. It is "you are what you eat" at the molecular level. Archaeologists use chemistry to reconstruct the past, learning what ancient people ate and drank, and discovering just how mobile they were. Migrants made up part of cities such as Cahokia across North America 1000 years ago, and formed part of the social fabric in cities throughout Mexico, Latin America, ancient Rome and across the world. Immigration is not a new phenomenon and likely not a new debate. Bone chemistry also has important applications in forensic cases, including identifying missing persons. We'll look at how science works to help us solve both ancient and modern mysteries.

    See this page for details.

  • Fri
    20
    Oct
    2017
    4:00 pmLewis 101

    Brian Daly
    Department of Physics and Astronomy
    Vassar College

    Picosecond Ultrasonics: Nanoscale Imaging and GHz Surface Acoustic Wave Studies

    Ultrafast lasers produce pulses of light that are less than 1 ps in duration, and can be used to generate and detect extremely high frequency ultrasound in the range of about 100 GHz. This technique can be applied to semiconductor metrology (nanometer scale thickness measurements, mechanical properties of thin films, imaging of sub-surface nanostructures) but also provides a window to the fundamental behavior of long-wavelength acoustic phonons that have a significant impact on thermal transport at the nanoscale. In this talk I will review the picosecond ultrasonic measurement technique and discuss recent work to advance nanoscale imaging and the study of surface acoustic waves.

  • Fri
    27
    Oct
    2017
    7:00 pmLewis Hall

    Frights, food and fun are the order of the evening when the University of Mississippi Department of Physics and Astronomy presents "Spooky Physics Demonstrations" from 7 to 9 p.m. Friday (Oct. 28) in Lewis Hall.

    The program will include a stage show at 8 p.m. Hands-on activities for the public through the evening include freezing objects in liquid nitrogen (at minus 320 degrees), generating sound waves with Bunsen burners and tubes, and levitating magnets with superconductors. Other fun presentations include optical illusions with mirrors, a Van de Graaff generator (a literally “hair-raising” electrical device), a bed of nails and other contraptions.

    Physics department personnel also will prepare ice cream with liquid nitrogen and award prizes for the most original, scariest and cutest costumes to kids aged 12 and under.

  • Sun
    29
    Oct
    2017
    6:30 pmKennon Observatory

    We are offering astronomy open houses and viewings with our telescopes:

    • October 29, 2017  6:30 - 9:00 PM

    We plan to observe  the Moon and other interesting objects. though our telescopes.  All these events are weather permitting. Admission is free.
    Children are welcome!

    See this page for the full schedule.

  • Tue
    31
    Oct
    2017
    4:00 pmLewis 101

    Shaon Ghosh
    Department of Physics
    University of Wisconsin - Milwaukee

    From the Ashes of a Pair of Neutron Stars: The Tale of a Kilonova

    The observation of the binary neutron star coalescence and the resulting electromagnetic counterpart by LIGO & Virgo and the various observing partners around the world has been one of the most amazing discoveries in physics and astronomy in recent times. The multitude of results that were obtained from this discovery, each in their own rights are fascinating. In this talk, I will attempt to condense these results and put them in the context of the efforts that have been carried out for many decades. I will first give a very short history of the subject, then I will talk about the description of the model of the physical process that we thought were responsible for the observed phenomenon. Next, I will talk about the proposed test to verify our model, and how we conducted them. Finally, I will summarize the important results of the multi-messenger observation.

  • Tue
    07
    Nov
    2017
    4:00 pmLewis 101

    Jake Bennett
    Department of Physics
    Carnegie Mellon University

    Prospects for Hadron Spectroscopy at Belle II

    The Belle II experiment, currently under construction at the KEK laboratory in Tsukuba, Japan, is the next generation of the highly successful B-factories. A substantial upgrade of both the Belle detector and the KEKB accelerator represent an essentially new experiment. Commissioning of the new SuperKEKB accelerator will start at the end of 2017. Physics running is planned to start in 2018 with a goal of collecting 50 times more data than the first generation B-factories. Belle II is uniquely positioned to make detailed studies of "exotic" hadron states, the so-called XYZ states, that provide the first possibility to explore long-conjectured, nonstandard quarkonium-like states. This talk will give an overview of the detector and accelerator upgrades and describe some of the capabilities of Belle II to explore both conventional and exotic bottomonium and charmonium physics.

  • Fri
    10
    Nov
    2017
    4:00 pmLewis 101

    Chris Moore
    Departamento de Fisica
    Instituto Superior Técnico — CENTRA, Portugal

    The Era of Gravitational Wave Astronomy

    The era of gravitational wave astronomy has begun. The LIGO and Virgo observatories are already revealing the properties of neutron star and stellar mass black hole coalescences. However, many more discoveries await. In the coming years we expect to observe gravitational radiation across a frequency spectrum spanning >10 orders of magnitude, generated by a diverse array of sources from white dwarf stars to supermassive black holes. I will discuss what I consider to be some of the most exciting prospects, and identify several key challenges that must be addressed for these discoveries to be fully utilised in the fields of astronomy, fundamental physics, and cosmology.

  • Tue
    14
    Nov
    2017
    4:00 pmLewis 101

    William E. East
    Perimeter Institute for Theoretical Physics, Canada

    Uncovering the Dynamics of Spacetime

    With the ground-breaking gravitational wave detections from LIGO/VIRGO, we have entered the era where we can actually observe the action of strongly curved spacetime originally predicted by Einstein. Going hand in hand with this, there has been a renaissance in the theoretical and computational tools we use to understand and interpret the dynamics of gravity and matter in this regime. I will describe some of the rich behavior exhibited by sources of gravitational waves such as the mergers of black holes and neutron stars. I will also discuss some of the open questions, and what these events could teach us, not only about the extremes of gravity, but about the behavior of matter at nuclear densities, the solution of astrophysical mysteries, and even the existence of new particles.

  • Tue
    14
    Nov
    2017
    6:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi

    Dr. Jason Hoeksema,
    Department of Biology,
    University of Mississippi

    Wild Mushrooms: Ecology, Edibility, and More

    What is a mushroom? What is it's natural function for fungi? Which ones are delicious and which ones will make you ill or worse? We will answer all these questions. We'll start with a discussion of fungal ecology, especially focusing on how fungi obtain food, and the really interesting ways that fungi can change the ecology of plants and nutrient cycling. We'll talk about the role of mushrooms in the life cycles of fungi. Finally, we'll discuss strategies for finding and safely enjoying wild mushrooms in northern Mississippi.

    See this page for details.

  • Thu
    16
    Nov
    2017
    2:45 pmLewis 101

    Leo Stein
    Walter Burke Institute for Theoretical Physics
    California Institute of Technology

    Probing Strong-Field Gravity: Black Holes and Mergers in General Relativity and Beyond

    General relativity—Einstein's theory of gravitation—has been studied for more than 100 years. Over the past century, we have learned that the theory agrees with all available experimental and observational tests. At the same time we know that the theory is incomplete, as it leads to inconsistencies when coupled with quantum mechanics.

    The strong-field regime is our best hope to study GR, both observationally and theoretically, and thus understand how to correct its shortcoming. In this talk, I will discuss investigations in the strong field, including black holes and neutron stars, in GR and theories beyond GR. The main focus will be predicting gravitational waves from merging black holes beyond GR. These predictions will allow for the most rigorous testing of general relativity, using LIGO, in the dynamical strong-field regime.

  • Thu
    16
    Nov
    2017
    4:00 pmLewis 101

    Graduate Students
    Department of Physics and Astronomy
    University of Mississippi

    Graduate Student Research Symposium