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Feiyan Cai
Department of Physics and Astronomy
University of Mississippi
Shaping Sound Waves for Advanced Acoustic Tweezers: From Fundamentals to Biomedical Applications
Optical tweezers, recognized with the 2018 Nobel Prize in Physics,
have showcased exceptional capabilities in manipulating micro-
and nanoparticles. In comparison, acoustic tweezers provide
stronger radiation forces, greater penetration depth, and reduced
thermaldamage, making them particularly suitable for biological
applications, especially in vivo. Nonetheless, traditional
acoustic tweezers face several challenges such as long
wavelengths, diffraction limits, and rigid designs, limiting
their precision and broaderapplication in biomedicine. In this
presentation, I will share our advancements in shaping sound
waves for advanced acoustic tweezers and address these
challenges. First, we designed localized gradient acoustic field
to create a precise platform for high-throughputcellular
manipulation. Second, we developed 3D acoustic tweezers to enable
multidimensional manipulation in complex environments. Third, we
innovated structured resonant fields to facilitate controllable
trapping and releasing, laying the groundwork for targeteddrug
delivery near vascular stents. Finally, I will outline my vision
for ultrasound-assisted drug delivery, both in vivo and in vitro,
and explore the future development of on-demand acoustic tweezer
technologies tailored for practical medical applications.
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Ashoka Karunarathne
Department of Chemical Engineering
New Jersey Institute of Technology
Coupled Ultrasonic-adsorption Studies of Porous Materials
Nanoporous materials are widely used as adsorbents due to their
high surface area and tunable structural properties. Fluid
confinement in nanopores significantly affects the overall
properties of fluid-saturated porous media, as well as the
properties of theconfined fluids themselves. These properties
include the elasticity of both porous media and the confined
fluid. As a result, there has been growing interest to understand
the mechanisms of fluid confinement, the properties of confined
fluids, and their relationwith the overall properties of the
fluid-filled porous media. In this presentation, I will discuss
the utilization of a novel experimental setup that couples
ultrasonic diagnostic with adsorption isotherm measurement to
study the elastic properties of water-sorbingporous materials.
Our recent studies of nanoporous glass, carbon xerogel, and
mycelium-based polymer composites have demonstrated the use of
ultrasonic wave propagation characteristics through water-sorbing
porous media to evaluate elastic moduli of porousmaterials, the
spatial distribution of water saturation, and the elasticity of
water confined in nanopores. Lastly, I will discuss the
development of an advanced ultrasonic-adsorption system that
enables volumetric adsorption measurements with a broad rangeof
fluids, not limited to water but also including organic compounds
such as hydrocarbons and alcohols.
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Mourad Oudich
Department of Physics
University of Lorraine, France
Tailoring Acoustic Wave Propagation Using Phononic Crystals and Metamaterials;
Phononic crystals and Acoustic/elastic metamaterials are
artificial materials designed to manipulate sound and vibration
for a myriad of applications. These structured materials are
generally constructed by alternating materials with different
mechanical propertiesand/or geometrical features, or by
incorporating resonators, to either display acoustic bandgaps or
enable other exotic acoustic functionalities that are not
attainable with natural materials. In this seminar, I will
present some of the research projects Ihave conducted recently,
in which I delineate the physical background and applications of
elastic metamaterials. I will first share our investigations on
acoustic wave propagation in media with time-varying mechanical
properties, and how we can realize suchmedia with active devices.
Secondly, I will present a real application of metamaterials to
achieve wireless ultrasound energy and data transfer through
metallic barriers without direct contact. I will conclude the
talk with my current exploratory projectson phononic crystals at
the gigahertz regime and metamaterials used for sensing
applications.
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Tousif Islam
Kavli Institute for Theoretical Physics
University of California — Santa Barbara
Taming Eccentricity in Binary Black Hole Mergers
Efficient detection and characterization of gravitational wave
(GW) signals from binary black hole (BBH) mergers require
computationally efficient yet accurate models for radiation
(waveforms) and remnant properties. While highly accurate
data-driven models exist for quasi-circular “binaries”
enabling key discoveries, such as large remnant kick velocities
in “GW200129” modeling eccentric binaries still
remains a challenge. In this talk, I will discuss recent advances
in eccentric BBH modeling. Using high-precision numerical
relativity and perturbative simulations, I will identify a
universal effect of eccentricity on radiation-related quantities,
providing a basis for defining eccentricity and developing
efficient models. I will also demonstrate how eccentricity
introduces additional radiation modes (which were predicted using
Newtonian calculations decades ago) and describe their extraction
using data-driven and signal processing techniques. Finally, I
will present the first data-driven model for these eccentric
harmonics (as well as the full radiation content).
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Madusanka Madiligama
Department of Physics and Astronomy
University of Mississippi
Rapid 3D Mapping of Underwater Sound Speed Using Sea Surface Data-based Machine Learning Model
Accurate underwater sound speed data is crucial for acoustic
propagation modeling and applications such as sonar systems.
However, due to limited data availability and computational
constraints, conventional methods face challenges in providing
real-time, high-resolution mapping of three-dimensional (3D)
sound speed fields. This study presents a machine learning model
that leverages readily available sea surface temperature and
salinity data from satellite observations to rapidly and
accurately estimate 3D underwater sound speed. The model is
trained to capture the relationships between surface data and
subsurface sound speed, integrating spatial and temporal
variables. Validation against in-situ profiling and Argo float
measurements demonstrates the model's ability to deliver
efficient, high-resolution 3D sound speed maps with reasonable
accuracy. This approach offers a significant advancement in
real-time underwater sound speed prediction, overcoming the
limitations of traditional methods. The results of acoustic
propagation modeling further suggest the model's applicability
for various underwater operations involving low- to mid-frequency
acoustic sources, including detection, communication, and noise
propagation.
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Purnima Narayan
Department of Physics and Astronomy
University of Mississippi
Investigating the Impact of Strong Gravitational Lensing on Tests of General Relativity using Gravitational Waves
The detection of gravitational waves (GWs) from binary black hole
(BBH) coalescences has emerged as a powerful and unique tool for
probing the strong-field dynamics of general relativity (GR).
This study delves into the potential biases introduced by strong
gravitational lensing on tests of GR with GW signals, since this
effect is not accounted for in the current implementation of
these tests. We assess the response of four standard
LIGO-Virgo-KAGRA tests of GR to simulated strong gravitationally
lensed BBH signals. Our findings highlight the need to rule out
mimicking biases due to strong lensing before claiming a GR
deviation.
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Nauman Ibrahim
Department of Physics and Astronomy
University of Mississippi
On the Road to Finding the Analog of Weyl Tensor for Causal Sets
I work on a theory of gravity called causal set theory (CST). It
posits that spacetime, at approximately Planck scales
(~10-35 m), is made out of “atoms of
spacetime”. Such a theory of gravity is motivated
from the search of a quantum theory of gravity, where there is
broad agreement that Einstein's continuous spacetime must give
way to some other fundamental structure at Planckian lengths. The
strength of CST is that it does this with the least amount of
ingredients: a set of the “atoms of spacetime” and a
partial order on them, i.e., which atoms are to the causal future
of which other ones, and where the number of atoms is defined to
be proportional to the volume of resulting spacetime. This
minimalism comes at a cost, however; even things which come
packaged in the definition of a spacetime metric, curvature etc.
become hard to find for a causal set. One such property of a
continuous spacetime is a part of the curvature tensor called the
Weyl tensor. It encapsulates, roughly, how the shape of sphere of
freely falling particles changes as it encounters the curvature
in the spacetime. My project is about finding the discrete analog
of the Weyl tensor for causal sets representing plane
gravitational waves. I am doing this by implementing an idea from
continuous spacetimes called geodesic deviation (how the distance
between two freely falling particles changes with an acceleration
proportional to the components of the Weyl tensor) in casual
sets. The challenge is that this implementation requires a lot of
numerical work in which some calculations grow in time complexity
as O(N3), where N is the number of atoms, thus a lot
of effort has to go into optimization.
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Michael Wallbank
Fermilab Accelerator Science & Technology facility
Fermi National Accelorator Laboratory
Accelerators for the Future: R&D at the Fermilab FAST Facility
High energy physics in the U.S. has ambitious plans requiring new
and improved accelerator technologies, including an upgraded
complex at Fermilab for DUNE, next-generation light sources, and
the potential of a future collider to be built on U.S. soil. To
address these requirements, Fermilab operates the Fermilab
Accelerator Science and Technology (FAST) facility, dedicated to
accelerator R&D. FAST includes an electron gun and
superconducting RF linac (up to 300 MeV), a storage ring, and an
upcoming proton source and injector line (up to 2.5 MeV). In
addition to the future of Fermilab accelerators, the broad
physics program includes general R&D with potential impact
across the DOE science program.
This colloquium will provide a basic introduction to accelerator
technologies and describe the principles of proton and electron
accelerators, including the challenges associated with
next-generation operations. We will discuss the exciting R&D
ongoing at FAST to address the required technological
advancements, focusing on Non-Linear Integrable Optics (NIO) for
improved beam intensity and Optical Stochastic Cooling (OSC) for
improved beam quality, and touching on a wide range of additional
ongoing research. I intend to make the content interesting and
accessible to those who have never taken any formal courses in
accelerator physics.
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Debasish Borah
Department of Physics
University of Pittsburgh
Why do We Live in a Universe Filled with Matter and no Antimatter?
The visible part of the present Universe is composed of matter
only with negligible trace of antimatter. However, matter and
antimatter are two sides of the same coin, and the Big Bang
should not have had a preference for creating one type over
another. Therefore, the observed dominance of matter over
antimatter in the present Universe has led to a longstanding
puzzle in particle physics and cosmology. This talk will discuss
some solutions to this puzzle within beyond standard model
frameworks and the possibility of probing them at particle
physics as well as gravitational wave-based experiments.
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Sashwat Tanay
Laboratoire Univers et Théories
Observatoire de Paris
Solutions to the Dynamics of Spinning, Eccentric Binary Black Holes
Accurate and efficient modeling of binary black hole (BBHs)
dynamics is crucial for detecting the gravitational waves (GWs)
they emit. In this talk, we will discuss our analytical solution
for the trajectories of spinning, eccentric BBHs. We will also
explore additional aspects of their dynamics, including their
constants of motion, separatrices, resonances (analyzed via
action-angle variables), and the potential emergence of chaos.
Our analysis is conducted within the framework of post-Newtonian
approximations up to orders 1.5 and 2.
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Igor Ostrovskii
Department of Physics and Astronomy
University of Mississippi
Detecting Massive Dark Particles and Locating Their Sources
Dark matter was first mentioned in 1884 (the Lord Kelvin: “stars with dark bodies”) and experimentally was evidenced in 1933 (Fritz Zwicky: “dunkle Materie”, that is “unseen/obscure matter.” In contemporary cosmology dark matter origin is associated with the “Big Bang.” My presentation is devoted to experimental observations of electrically neutral massive particles (Mp) emitted by the Sun. Their rest mass is orders of magnitude higher than those of a neutron, which basically made them invisible (dark) to existing astronomical, high-energy or particle physics instruments. Four series of ground-based experiments and their explanations resulted in the development and patenting a new detector of massive particles; Inventor: Igor Ostrovskii, Patent Number: US 11,927,705 B2, 2024. Title: “Apparatus And Methods for Detecting Massive Particles, Locating Their Sources and Harvesting Their Energy.” The presentation includes the following main results: 1. Invented “crystal pendulum” with laser-doppler vibrometer optical and electrical detection. 2. Gravitational effect of Mp-particles on crystals. 3. Influence of Mp-particles on free-vibrating quartz resonators. 4. Micro voids in fused quartz and glass. Main conclusions: 1) The gravitational and quantum-mechanical mechanisms are responsible for interaction of Mp-particles with matter. 2) Mp-particle rest mass is (5.3 ± 1.7) × 10-21 kg and Mc2 = (3.1± 1) × 1015 eV. 3) The speed of Mp-particles in space between the Sun and Earth is (249 ± 1) km/s, which falls in the speed of slow solar wind. |
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Adam Lister
Department of Physics
University of Wisconsin — Madison
Looking for Sterile Neutrinos with the NOνA Experiment
Neutrino oscillations, whereby one flavour of neutrino changes
to another as it travels, has been a exciting area of study over
the last several decades. This process has mostly been
interpreted within a framework that has three neutrinos, each
paired with one of the charged leptons, but a number of anomalous
results have been reported since the early 2000s which don't
appear to fit within this model. One potential explanation for
these anomalies is an additional "sterile" neutrino, which would
not interact via the weak force, but could impact neutrino
oscillations. A number of experiments have searched for such a
particle, but so far no consistent picture has emerged. The
NOνA experiment is a long-baseline neutrino experiment
comprised of a Near Detector 1 km from the beam source on-site at
Fermilab, Batavia, IL and a Far Detector located 810 km away in
Ash River, MN. In this colloquium, I will give an overview of the
status of sterile neutrino searches in the field, and present
NOνA's most recent sterile neutrino search.
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Vijay Varma
Mathematics
University of Massachusetts — Dartmouth
Leveraging Numerical Relativity and Data-Driven Models for Gravitational Wave Astronomy
Numerical relativity simulations play a central role in
gravitational-wave astronomy, as they are the only means to solve
Einstein's equations near the mergers of black holes and neutron
stars and predict the gravitational wave signal. However, these
simulations are too expensive for directly analyzing the signals
observed by detectors like LIGO. I will talk about data-driven
surrogate models that efficiently interpolate between
simulations, bringing the evaluation time down from months to a
fraction of a second. These models rival the simulations
themselves in accuracy and bring the power of numerical
relativity to gravitational wave applications ranging from black
hole astrophysics to tests of general relativity. I will discuss
how surrogate models are already enabling precision astrophysics,
such as extracting recoil velocities from black hole mergers and
improved spin measurements. Finally, I will discuss the crucial
role such machine learning inspired models will play in realizing
the science potential of future observatories like LISA and
Cosmic Explorer.
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Eve Vavagiakis
Department of Physics
Duke University
A New Generation of Millimeter and Submillimeter Observations for Cosmology and Astrophysics
In our exciting era of experimental cosmology, rapid developments
in instrumentation and highly sensitive superconducting detectors
have provided a wealth of arcminute-scale cosmic microwave
background (CMB) data. These measurements are transforming our
understanding of the evolution of our cosmos. I will present
recent results from the Atacama Cosmology Telescope and discuss
how our high-resolution CMB maps are at the frontier of
“Sunyaev–Zel'dovich effect” science. I will
also summarize the design and status of first light instruments
for the CCAT Observatory and the Simons Observatory. These
experiments will provide unparalleled measurements of the
millimeter and submillimeter sky, offering rich opportunities for
cross-correlation studies with upcoming surveys and paving the
way towards CMB-S4, the next-generation ground-based CMB
experiment. This will enable novel multifrequency science in the
coming years, testing cosmological models and opening new windows
on galaxy evolution and fundamental physics. |
