Events
-
Tue16Feb20166:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi
Katherine Dooley and Marco Cavaglià
Department of Physics and Astronomy
University of MississippiObservation of Gravitational Waves from a Binary Black Hole Merger.
On September 14, 2015 at 03:50:45 a.m. CST the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a
transient gravitational-wave signal. The signal matches the prediction of
general relativity for the coalescence of two black holes weighting about
30 Suns into a single black hole at a distance of over one billion light
years from Earth. This is the first direct detection of gravitational
waves and the first observation of a binary black hole merger.
See this page for details. -
Tue08Mar20164:00 pmLewis Hall 101
Ken Bader
Department of Internal Medicine
University of CincinnatiMechanical Ablation of Tissue with Focused Ultrasound
Histotripsy is a transcutaneous focused ultrasound therapy that ablates tissue through the mechanical oscillations of microbubbles, or cavitation. Preclinical studies have found histotripsy effective for the treatment of prostate pathologies, cancer, deep vein thrombosis, and congenital heart disease. In this talk, the forms of histotripsy and their ablative mechanisms will be modeled in silico, and image-guidance techniques for mechanical ablation will be discussed. An analytic model will be presented to predict the extent of the treatment zone. This analytic model can be used for treatment planning, and to aid the FDA in the development of regulatory standards for histotripsy. Image-guidance of histotripsy will be demonstrated with a new ultrasound imaging modality called passive cavitation imaging (PCI). Studies in a prostate phantom demonstrate that PCI correlates well with the width of the ablation zone, indicating PCI can be used as a predictive metricfor tissue ablation from histotripsy. Finally, PCI will be used to monitor cavitation when histotripsy is used in combination with a lytic agent to lyse clots in a model of deep vein thrombosis. A significant improvement was observed in the thrombolytic efficacy for the combination treatment over histotripsy alone, suggesting a synergistic effect between histotripsy and the lytic agent.
-
Sun20Mar20167:40 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
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. -
Tue22Mar20164:00 pmLewis Hall 101
Thomas Sotiriou
School of Physics & Astronomy
University of NottinghamBlack Holes Without Relativity
Lorentz symmetry is central to the concept of a black hole, as it precludes superluminal motion. It is not obvious that one can even define what a black hole is if Lorentz symmetry is abandoned, so one might expect that any observational evidence supporting the existence of black holes will impose very stringent constraints on Lorentz violations. I will discuss some basic aspects of causality in theories that violate Lorentz symmetry and I will argue that, remarkably, the concept of a black hole survives in these theories. After defining the appropriate notion of black hole, I will explore their basic aspects and discuss how they differ from black holes in General Relativity.
-
Tue22Mar20166:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi
Joel Mobley
Department of Physics and Astronomy
University of MississippiThe physics of MRI
Magnetic resonance imaging (MRI) has revolutionized the diagnosis and treatment of a broad spectrum of medical conditions. Since its clinical debut in the 1980ʼs, it has evolved to provide a level of anatomical detail not possible with any other imaging modality, all without the focus of an ultrasound probe or the directionality of an x-ray beam. The fundamental principles at work in MRI include quantum physics, spinning tops, flipping magnets and simple patterns of bright and dark. The aim of this talk is to remove some of the mystery of how the manipulation of the weakest
magnets in the atom leads to the MR image and to look at emerging medical treatments enabled by
MRI. -
Tue29Mar20164:00 pmLewis Hall 101
Richard Brito
Gravitation in Técnico
Instituto Superior Técnico — CENTRAInteraction Between Bosonic Fields and Compact Objects
Fundamental bosonic fields generically arise as possible dark matter candidates and in extensions of General Relativity, but are also a useful proxy for more complex interactions. In this talk I will discuss the rich phenomenology of fundamental bosonic fields around black holes and compact stars. In particular I will discuss: (i) the interaction of self-gravitating bosonic structures with compact stars; (ii) superradiant instabilities around black holes and how it can be used to constrain particle masses.
-
Tue05Apr20164:00 pmLewis Hall 101
Pengfei Zhang
Department of Mathematics
University of MississippiHomoclinic Intersections for Geodesic Flows on Convex Spheres
Transverse homoclinic intersection was discovered by Poincare in the study of stability properties of periodic orbits of n-body problem. Poincare realized that this is a mechanism which not only destroys the stability of periodic orbits but also leads the existence of chaos in the phase space.
In this talk, we will study the geodesic flows on convex spheres. We show that, generically, every closed geodesic is either hyperbolic or irrationally elliptic. Moreover, every hyperbolic closed geodesic admits some transverse homoclinic intersection. Therefore, (everywhere) chaotic dynamics can happen generically on manifolds with simple/trivial topology.
-
Tue12Apr20164:00 pmLewis Hall 101
Greg Dooley
Kavli Institute for Astrophysics and Space Research
Massachusetts Institute of TechnologyTidal Stripping with Self-Interacting Dark Matter
Self-interacting dark matter (SIDM) postulates that dark matter is not entirely collisionless, but self scatters at a low rate. By transforming dark matter halo cusps to cores, SIDM offers a solution to the “too big to fail” problem and cusp/core problem in the Milky Way and local field. Two classes of models exist, with velocity-independent and velocity-dependent cross sections. While tight constraints exist on velocity-independent models, constraining velocity-dependent models remain elusive. In this talk, I discuss the implications of both types of SIDM on the tidal disruption of satellite galaxies in a Milky Way-like host. While the total dark matter mass loss rate is not affected, stellar mass loss is enhanced due to lower binding energy in subhalo cores. I discuss the variables affecting the strength of the increased stellar mass loss rate, the effect on observables in the Milky Way, and where we need to look to further constrain or identify self-interacting dark matter.
-
Sun17Apr20168:00 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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. -
Tue19Apr20164:00 pmLewis Hall 101
Alexander B. Yakovlev
Department of Electrical Engineering
University of MississippiNon-local Susceptibility of the Wire Medium in the Spatial Domain Considering Material Boundaries
The interaction of electromagnetic waves and wire media has been of interest for many years, driven by applications utilizing artificial plasma, epsilon-near-zero materials, negative refraction, wave canalization and other uses. When the period of the wires is small compared to wavelength, the structure can be considered as a homogeneous (homogenized) medium. Early models of wire media neglected spatial dispersion of the homogenized material, but it has more recently been shown that non-local effects are verystrong for wire media and often cannot be ignored.
In this work, we show that the non-local susceptibility for a nontranslationally invariant homogenized wire medium is, modulo a constant, given by a simple Green's function related to the material geometry. We also show that two previous methods for solving wave interaction problems for bounded wire media (wave expansion method and transport equation) are equivalent to each other, and to a third method involving particle reflection at the boundary. We discuss the importance of the dead layer or virtual interface, and find it to be analogous to the excitonic semiconductor case. Several examples are provided to clarify the material.
-
Tue26Apr20164:00 pmLewis Hall 101
Ahmed Rashed
Department of Physics and Astronomy
University of MississippiNon-standard Tau Neutrino Interactions
We now know that neutrinos have masses and that there is a leptonic mixing matrix just as there is a quark mixing matrix. The existence of neutrino masses and mixing requires physics beyond the standard model (SM). Hence, it is not unexpected that neutrinos could have new interactions beyond the standard model, or non-standard interactions (NSI). The effects of NSI have been widely considered in neutrino phenomenology. Bounds have been set on the NSI parameters. I will discuss the impact of the NSI on the measurement of neutrino mixing parameters such as the atmospheric and reactor mixing angles, mass hierarchy, and CP violation. We include form factor effects in our calculations and find the deviation of the actual mixing angle from the measured one, assuming the standard model cross section, can be significant and can depend on the energy of the neutrino.
A key property of the SM gauge interactions is that they are lepton flavor universal. Evidence for violation of this property would be a clear sign of new physics (NP) beyond the SM. Recently, hints of lepton flavor non-universality emerged from B-meson decay channels observed in the BaBar and LHCb experiments. We proposed tests of lepton flavor non-universality in tau-neutrino scattering. Different models have been introduced in this study of which charged Higgs, W', and Leptoquark.
-
Tue26Apr20166:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi
Breese Quinn
Department of Physics and Astronomy
University of MississippiParticle Physics: The Sledgehammer and the Tweezer
Particle physics is the field of research that seeks to discover and understand the most fundamental building blocks of the universe, and how they interact to form everything around us. One way to do this type of research is using the biggest machines in the world to smash particles together as hard as possible, and see what new comes out. We will take a look at the discovery of the Higgs Boson to examine this sledgehammer approach. Another method is using very sensitive tools to make high precision measurements of extremely rare processes. An introduction to the new Muon g-2 experiment will demonstrate this tweezer approach. We will discuss Ole Missʼ role in both of these efforts, as well as why it all matters.
-
Mon09May2016Sunrise - 2 PMKennon Observatory
The planet Mercury will pass in front of the Sun, which is called a transit. This will start before Sunrise at 6:12 AM and end at 1:42 PM (CDT). It will be most visible about 10 AM. However, since this requires looking directly at the sun appropriate filters or a projection system must be used.
The physics and astronomy department is hosting an open house at the Kennon observatory next Monday (May 9th) to observe the transit of Mercury occurring that morning. The public is invited to see this relatively rare event through filtered solar telescopes, as it is dangerous to look directly at the sun.
The open house will will begin at 9 AM and end around noon unless inclement weather makes it impossible to watch the event. Come with your family and friends to watch the Sun and the passage of Mercury across the face of the Sun.
-
Tue10May201611:00 amLewis Hall 101
The 2016 induction ceremony for the National Physics Honors Society, ΣΠΣ will take place on May 10 at 11:00 AM in room 101 in Lewis Hall.
-
Sat14May201611:30 am - 1:00 pmLewis Hall room 104
The Department of Physics and Astronomy is hosting a buffet luncheon honoring the 2016 graduating students. Family and friends are invited to attend.
Undergraduates:
Forrest N. Gamble
Jeffrey D. Atkinson
Piero R. Bracamonte
Hunter A. Gabbard
Peshani Herath
Jared K. Wofford
Graduates:
Shanmuka Shivashankara - Ph.D.
Sumudu P. Tennakoon - Ph.D.
Salman Allahiad - M.A.
Mohsen Rezaeizaheh - M.A.
Nazanin Omidi - M.S. (August) -
Mon06Jun2016Tue07Jun20169:00 AM – 4:00 PMJackson Avenue Center, G08, University of Mississippi, Oxford
Two-day workshop, teachers will learn the basics of sound waves, light waves, and gravitational waves, a new kind of wave that has recently been observed for the first time. See http://umcmse.com/waves-here-there-and-everywhere/ for details.
-
Mon27Jun2016Tue28Jun20169:00 a.m. - 5:00 p.m.Lewis Hall, University of Mississippi
The department is hosting a 2 day QuarkNet Teacher Workshop on June 27 and June 28. We will discuss the detection of Dark Matter, SuperSymmetry, and Cosmic Rays. Teachers will learn how to operate cosmic ray detectors and take activities back to their class rooms. Contact the Department of Physics and Astronomy if you are a high school Physics teacher and are interested in the QuarkNet program.
You can find more out about QuarkNet at the wiki site: https://en.wikipedia.org/wiki/QuarkNet
(For more information please contact Dr. Cremaldi at cremaldi@phy.olemiss.edu)
-
Sun10Jul20168:30 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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. -
Tue30Aug2016
-
Sun11Sep20167:30 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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. -
Tue13Sep20164:00 pmLewis Hall 101
Michael S Turner
Kavli Institute for Cosmological Physics
University of ChicagoThe Big Picture: What We Know About How the Universe Began and What We Are Trying to Find Out
Today the Universe is made out of dark matter, dark energy and a small amount of ordinary matter (the atoms we are made of). We can trace the history of the Universe back to when it was a microsecond and was a formless quark soup. We now have good evidence for an early burst of tremendous expansion (inflation) that stretched sub-atomic quantum fluctuations to astrophysical size and created the seeds for galaxies. But there is much to figure out, including what dark matter is made of, what the nature of the mysterious dark energy is, and when inflation took place.
-
Tue13Sep20166:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi
Michael S Turner
Kavli Institute for Cosmological Physics
University of ChicagoEinstein's Outrageous Universe: Gravitational Waves, Black Holes and the Big Bang
Dr. Michael Turner, Bruce V. & Diana M. Rauner Service Professor of Physics and Astronomy and Director of the Kavli Institute at the University of Chicago will discuss the biggest mysteries of modern cosmology. Is the universe finite or infinite? What is speeding up the expansion of the universe? Turner will present the current state of knowledge about modern cosmology, from the discovery of cosmic expansion to dark matter and dark energy.
-
Tue20Sep20164:00 pmLewis Hall 101
Don Summers et al.
Department of Physics and Astronomy
University of MississippiFascinating Physics Demonstrations
Fifty minutes of fascinating physics demonstrations, including milk jug rockets, will be presented.
-
Tue27Sep20164:00 pmLewis Hall 101
Don Summers Presenting
Department of Physics and Astronomy
University of MississippiPowers of Ten
Powers of Ten illustrates the universe as an arena of both continuity and change, of everyday picnics and cosmic mystery. It begins with a close-up shot of a man sleeping near the lakeside in Chicago, viewed from one meter away. The landscape steadily moves out until it reveals the edge of the known universe. Then, at a rate of 10-to-the-tenth meters per second, the film takes us towards Earth again, continuing back to the sleeping man's hand and eventually down to the level of a carbon atom.
-
Sun09Oct20167:00 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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. -
Tue11Oct20164:00 pmLewis Hall 101
Mike Reep and Scott Watkins
Dept. of Physics and Astronomy
University of MississippiMachine Shop Physics
Abstract
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.
-
Tue11Oct20166:00 pmLuca Bakery and Cafe, 1120-1122 North Lamar Blvd Oxford, Mississippi
Dr. Arne – R. Diercks,
School of Ocean Science and Technology
University of Southern MississippiPerpetual Snow - Sedimentation in the Deep Sea
Sedimentation in the deep ocean is a slow and steady supply of material to the deep sea via small particles. Once glued together by organic matrices into larger aggregates, they become a main source of energy, food and sediments in the deep sea and the seafloor. Sedimentation rates in the deep ocean are small, ranging from a fraction to a few millimeters per year in the abyssal ocean. Anthropogenic impacts can alter the sedimentation even in remote areas. Following the Deep Water Horizon Oil Spill in the northern Gulf of Mexico, anthropogenic oil marine aggregates that had formed in the water column near the wellhead, were deposited as an unprecedented large amount of material on the seafloor within a few months following the spill.
-
Tue18Oct20164:00 pmLewis Hall 101
Chandrima Chatterjee
Department of Physics and Astronomy
University of MississippiExperimental Investigation of Impurities and Their Effect on Acousto-Electric Properties of Lithium Niobate
The functional parameters of Lithium niobate that is used in various acousto-opto-electronic applications are questionable. The nonclassical nonlinear effect such as “acoustical memory” is not explained at full. Despite there being publications on crystal defects in Lithium niobate, the relationship between the defects and Acoustical Memory has not yet been established. Previous publications analyzed the Acoustical Memory effect without going into the microstructural detail of the level of point defects. The purpose of this research is to establish a connection between the microscopic point defects and the macroscopic nonlinear phenomena. The present research aims at finding new crystal characteristics including the identification of impurities and point defects, the distribution of the defects along the optical crystallographic z axis, and in a direction normal to the z axis. Bulk crystals and wafers are studied. The impurities are identified by their characteristic lines in the photoluminescence spectra, which are taken at room temperature in a range of 350 to 900 nm. The spectra reveal the following point defects: Ar, Ba, Cs, F-color center, Rb, Ru, Sn, Fe, K, Li, O, Nb, Kr, NbLi4+, Xe, etc. The peak corresponding to the F-center is found at 400.429 nm and has the highest number of photon counts. Further, the samples are shifted with a step of tens of microns along the z-axes or normal to it. This optical scanning allows to find a distribution of the impurities in the samples. The photon counts changes with crystal position for some impurities. The distribution of these defects is observed as peaks and valleys. The results may be used to discover the physical mechanisms behind nonclassical nonlinear phenomena in Lithium niobate.
-
Tue25Oct20164:00 pmLewis Hall 101
Matteo Rini
Deputy Editor
American Physical SocietyScience Communication: Take Charge of It!
Scientists have a responsibility to share the meaning and implications of their work, but receive little training in communication, and often feel unprepared to communicate with the public, the media, public officers and others outside their own field. In this talk, I will discuss how our journal Physics (htttp://physics.aps.org) strives to communicate research to a broad audience and share some thoughts and tips on science communication from my experience as a writer, editor, press officer and scientific consultant to policy makers.
-
Fri28Oct20167:00 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.
-
Tue01Nov20164:00 pmLewis Hall 101
-
Sun06Nov20166:00 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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. -
Tue08Nov20164:00 pmLewis Hall 101
Mairi Sakellariadou
Department of Physics
King's College — LondonUnweaving the Fabric of the Universe
Our conventional understanding of space-time, as well as our notion of geometry, break down once we attempt to describe the very early stages of the evolution of our universe. The extreme physical conditions near the Big Bang necessitate an intimate interplay between physics and mathematics. The main challenge is the construction of a theory of quantum gravity, the long-sought unification of Einstein's general relativity with quantum mechanics. There are several attempts to formulate such a theory; they can be tested against experimental and observational results coming from high energy physics and astrophysics, leading to a remarkable interplay between gravity, particle physics and cosmology.
-
Fri11Nov20164:00 pmLewis Hall 109
-
Tue15Nov20164:00 pmLewis Hall 101
Karelle Siellez
Center for Relativistic Astrophysics
Georgia Institute of TechnologyThe Coincidence Between Gamma-Ray Bursts and Gravitational Waves: the Dawn of the Multi-Messenger Era!
Last year, while we celebrated the 100th anniversary of the Theory of the General Relativity of Einstein, we also detected the first direct observation of Gravitational Waves. LIGO opened the new area of Gravitational Wave Astrophysics with the detection of the coalescence of two black holes. Neutron star mergers (either double neutron star or neutron star - black hole systems) and collapsing massive stars are the next candidates for the detection of Gravitational Waves. They are though to be also the progenitor of respectively short and long Gamma-Ray Bursts. A detection in coincidence of both the Gravitational Waves and the electromagnetic emission would open the era of multimessenger astrophysics.
To detect those coincidences between GRB and GW, LIGO uses a different analysis that searches for a GW triggers coincident within some time window and sky position of a GRB in nearly real time thanks to the GCN sent by the satellite. We estimated the rate of coincident events that could be detected during the next run of O2 using observations in one hand and Monte Carlo simulations on the other. The small number of coincidence could be improved by using the untriggered GRBs missed by the Fermi GBM satellite. Thanks to a new code developed by the GBM team, we will discuss about the new kind of coincident detection that we could obtain.
This talk will describe the search of Gravitational Waves associated to GRBs. We will show the motivations and analysis made for the untriggered searches as well as the implication of those untriggered GRB on the expected rate of coincident event, the classification of long and short GRBs, and the possible new kind of progenitor for short GRBs at low redshift.
-
Sun04Dec20165:30 pmKennon Observatory
We are offering astronomy open houses and viewings with our telescopes:
We plan to observe the Moon, planets, 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.