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Jake Bennett, etc.
Department of Physics and Astronomy
University of Mississippi
What can you do with a Physics degree?
Undeclared, interested in exploring other majors, or
just curious about the Department of Physics and
Astronomy? Want to prepare for professional school or
just develop the tools and qualities employers value
most? Join us to discover what a degree in Physics can
do for you. You will also get the chance to observe
some fun and interesting demonstrations.
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Martin Frank
Department of Physics
University of South Alabama
First Results from NOνA's Magnetic Monopole Search
The existence of the magnetic monopole has eluded
physicists for centuries. The NOνA far detector
(FD), used for neutrino oscillation searches, also has
the ability to identify slowly moving magnetic
monopoles (v < c /100). With a surface area of 4,100
m2 and a location near the earth's surface,
the 14 kt FD provides us with the unique opportunity to
be sensitive to potential low-mass monopoles unable to
penetrate underground experiments. We have designed a
novel data-driven triggering scheme that continuously
searches the FD's live data for monopole-like
patterns. At the offline level, the largest challenge
in reconstructing monopoles is to reduce the 148,000 Hz
speed-of-light cosmic ray background. In this talk, I
will present the first results of the NOνA monopole
search for slow monopoles.
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Shawn Pollard
Department of Physics and Materials Science
University of Memphis
Designing Chiral Magnetism Through Interface Engineering – From Skyrmions to Magnetic Memory
Chirality is a fundamental concept in condensed matter
physics. The ability to control magnetic chirality
through broken symmetry at interfaces has led to the
development of new devices governed by control of the
local spin structure. One such structure, the skyrmion,
a result of the Dzyaloshinskii-Moriya interaction
(DMI), has been proposed as both a building block of
new spintronic devices and as a tool to probe a variety
of novel electrical transport phenomena. In this talk,
I will describe our efforts to design chiral structures
including skyrmions with tunable stability and dynamics
by modifying the interface properties in both heavy
metal/ferromagnet bi- and multilayers. We find that by
tuning the heavy metal and ferromagnetic layer
thicknesses and repetition numbers, we can control the
skyrmion boundary structure, which has profound effects
on its dynamics. This includes the first observation of
an interlayer DMI in which a breaking of domain wall
degeneracy can be used to prevent off-axial current
driven skyrmion motion known as the skyrmion Hall
effect. I also discuss our work developing new
techniques in which to quantify magnetic phenomena in
these materials.
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Samrat Choudhury
Department of Mechanical Engineering
University of Mississippi
Machine Learning Enabled Multi-Scale Modeling of Materials
Traditional computational investigation of
processing-chemistry-structure-property linkage in
materials science involves the usage of specialized
computational tools at discrete length scales
ranging from electronic to atomic to mesoscale.
Alternatively, over the past two decades, a
multi-length scale approach combining simulation tools
at different length scales has been adopted where
electronic/atomic information from lower length scale
is passed to higher length scale. However, such
traditional computational approaches can provide only
limited insights into a highly complex set of
interactions spanning over multiple length and time
scales each of which are linked to the property and
performance of the materials, thus requiring an
out-of-the box approach. In this presentation, I will
focus on the application of machine learning tools to
guide simulations at multiple length scales to augment
the capabilities of traditional computational tools.
Further, it will be shown that machine learning enabled
computational approach provides a fast and efficient
pathway to navigate the vast processing, microstructure
and chemical search space for a targeted property, a
departure from the traditional time consuming and
expensive Edisonian trial-and-error approach based on
synthesis-testing experimental cycles.
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Sudeep Adhikari
Department of Physics and Astronomy
University of Mississippi
Universality in Activated Barrier Crossing
The thermal activation process by which a system passes
from one local energy minimum to another by crossing an
energy barrier is a recurring motif in physics,
chemistry, and biology. For instance, biopolymer chains
are typically modeled in terms of energy landscapes,
with folded and unfolded configurations represented by
two distinct wells separated by a barrier. The rate of
transfer from the unfolded to folded state depends most
importantly on the height of the barrier with respect
to the temperature of the heat bath—but also in
seemingly idiosyncratic ways on the details of the
shape of the barrier. We consider the case of bias due
to an external force, analogous to the pulling force
applied in optical tweezer experiments on biopolymers.
We identify the universal behavior of the barrier
crossing process and demonstrate that data collapse
onto a universal curve can be achieved for simulated
data over a wide variety of energy landscapes having
barriers of different heights and shapes.
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John Waite
Department of Physics and Astronomy
University of Mississippi
Flavor SU(3) in Cabibbo-favored D-meson Decays
Model-independent description of nonleptonic decays of
charmed mesons is a challenging task due to the large
nonperturbative effects of strong interactions on the
transition amplitudes. We discuss the equivalence of
two different flavor-SU(3)-based descriptions of
Cabibbo-favored non-leptonic decays of charmed mesons
to two-pseudoscalars final states including the η
and η′ mesons.
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Zara Bagdasarian
Department of Physics
University of California — Berkeley
Reaching for the Stars with CNO Solar Neutrinos and Other Adventures of Novel Neutrino Detectors
The latest breakthrough in neutrino physics is the
first experimental evidence of the
carbon-nitrogen-oxygen (CNO) fusion cycle in the Sun.
The discovery was possible due to the unprecedented
radiopurity of the Borexino liquid-scintillator
detector (Italy), employing innovative hardware and
software developments. In the future, new technologies
can further facilitate access to a broad physics agenda
and applications in neutrino physics. Of particular
interest are the cutting-edge detection techniques and
novel target materials that aim to fully utilize both
scintillation and Cherenkov signals from low- and
high-energy neutrino interactions. The first
deployment of Large Area Picosecond Photodetectors
(LAPPDs) and water-based liquid scintillator (WbLS) in
the ANNIE experiment at Fermi National Accelerator
Laboratory (USA) will be exciting milestones in the
evolution of neutrino detection. Neutrino Experiment
One (NEO) will be the first ktonne-scale detector built
by the Watchman collaboration at Boulby Underground
Laboratory (UK). Its goal is to demonstrate, for the
first time, nuclear non-proliferation capabilities
using antineutrino detection. Finally, the multi-ktonne
detector, Theia, aims to detect solar neutrinos,
determine neutrino mass ordering and the CP-violating
phase, observe diffuse supernova neutrinos and
neutrinos from a supernova burst, search for nucleon
decay, and, ultimately, neutrinoless double beta decay.
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Alexandru Lupsasca
Department of Physics
Princeton
The Black Hole Photon Ring
The photon ring is a narrow ring-shaped feature,
predicted by General Relativity but not yet observed,
that appears on images of sources near a black hole. It
is caused by extreme bending of light within a few
Schwarzschild radii of the event horizon and provides a
direct probe of the unstable bound photon orbits of the
Kerr geometry. I will review the origin and structure
of the photon ring, before discussing the prospects for
its future detection. I will argue that the precise
shape of the observable photon ring is remarkably
insensitive to the astronomical source profile and can
therefore be used as a stringent test of strong-field
General Relativity. A space-based interferometry
experiment targeting the photon ring of M87* could test
the Kerr nature of the source to the sub-sub-percent
level.
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Kathy Gunn
Department of Oceanography
Commonwealth Scientific and Industrial Research Organisation (Australia)
Vertical Mixing and Heat Fluxes Conditioned by
a Seismically Imaged Oceanic Front
The southwest Atlantic gyre connects several distinct
water masses, which means that this oceanic region is
characterized by a complex frontal system and enhanced
water mass modification. Despite its significance, the
distribution and variability of vertical mixing rates
have yet to be determined for this system.
Specifically, potential conditioning of mixing rates by
frontal structures, in this location and elsewhere, is
poorly understood. Here, we analyze vertical seismic
(i.e., acoustic) sections from a three-dimensional
survey that straddles a major front along the northern
portion of the Brazil-Falkland Confluence. Hydrographic
analyses constrain the structure and properties of
water masses. By spectrally analyzing seismic
reflectivity, we calculate spatial and temporal
distributions of the dissipation rate of turbulent
kinetic energy, ε, of diapycnal mixing rate,
K, and of vertical diffusive heat flux,
FH. We show that estimates
of ε, K, and FH
are elevated compared to regional and global mean values.
Notably, cross-sectional mean estimates vary little over a
6 week period whilst smaller scale thermohaline structures
appear to have a spatially localized effect
upon ε, K,
and FH. In contrast, a mesoscale
front modifies ε and K to a depth of
1 km, across a region of O(100) km. This front clearly
enhances mixing rates, both adjacent to its surface
outcrop and beneath the mixed layer, whilst also locally
suppressing ε and K to a depth of 1 km.
As a result, estimates of FH
increase by a factor of two in the vicinity of the surface
outcrop of the front. Our results yield estimates
of ε, K and FH
that can be attributed to identifiable thermohaline
structures and they show that fronts can play a
significant role in water mass modification to depths of
1 km. |
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Saptaparna Bhattacharya
Department of Physics and Astronomy
Northwestern University
An Experimental Overview of Effective Field Theory Exploration at the LHC
The effective field theory (EFT) approach posits that
in a scenario where new particles cannot be observed
directly at low energy, the source of new physics are
heavy fields beyond our current reach. The Standard
Model (SM) Lagrangian contains fields of dimension-4
and the EFT frame-work extends the SM Lagrangian in an
expansion in inverse powers of the scale of new
physics. Within this framework, the potential impact of
higher dimensional operators can be explored. The most
common example of an EFT appears in the Fermi theory of
weak interactions where the appearance of the four
Fermi vertex features an operator of dimension-6. In
this talk, I will provide an overview of EFT
explorations at the LHC. With the collection of more
than 150 fb-1 of data at the LHC, rare
processes predicted in the Standard Model have become
accessible. These rare processes can be used as probes
of new physics using the EFT framework. The large
dataset also enables precision measurements of certain
processes allowing the ability to study deviations from
SM expectations and characterizing the nature of
potential excesses within the EFT formalism. I will
focus on the exploration of dimension-6 and dimension-8
operators at the LHC in final states arising out of the
decay of multiple gauge bosons. I will provide a
snapshot of LHC Run II analyses as we embark on Run III.
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