Initiated by Babak Seradjeh in 2012, the Department of Physics and the Physics Club started a new seminar series for undergraduate students. All students are encouraged to participate.
Preparing and giving a good talk is a very important skill that will serve you, undergraduate students, well in your future career. But it's not usually something you get a lot of practice with in your regular course work. This seminar series is an opportunity for you to gain experience by presenting a topic your are interested in to an audience of your peers and some faculty. Even if you are not presenting, this is a great opportunity to learn about a new topic and get to know what your peers are interested in.
The talks may be short or long, may use slides or blackboard, and can be as formal or casual as you'd like them to be. But they need to convey a good story with an introduction and some identifiable conclusions. The topics could be based on your past or current research experience, such as REUs, honors thesis, work, etc., or something you might be interested in learning more about, or even a problem or subtopic from a course, say Quantum Mechanics, that you have recently encountered and is interesting. If needed, we shall try to secure faculty support and advising for specialized areas.
Feel free to contact me if you would like to give a talk, have a suggestion, or if you have any questions.
Resources for giving a good presentation
A good presentation must tell a good story: engaging, to the point, conveying a coherent message, and fun (if at all possible!).
There are many guides and resources out there on how to give an effective presentation. Here, I've collected a few that you might find useful. You can also come and talk to me. If you are giving a talk in this seminar series, I will look at your slides, notes, etc. and give you feedback. If you are considering giving a talk, I will help you out with choosing a good topic and preparing the presentation.
Abstract: Symmetries and their groups play an important role in our physical description of the universe. Symmetries are not only useful for simplifying physical systems (like assuming spherical symmetry for an approximate solution). In certain cases, they tell us something more fundamental about a system.
In this lecture, I will give a crash course in group theory: finite groups, Lie groups, infinitesimal generators (all with examples!). The second part of the talk will be devoted to discussing how a mathematical idea like a symmetry is applied to physics. This will include discussion about Noether’s theorem, CPT symmetry, and Lorentz symmetry. The discussion of CPT symmetry will include how it is used in current experiments to probe fundamental physics.
Trigger Design for Di-Higgs Production at ATLAS
Abstract: The Large Hadron Collider (LHC), located at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland, collides protons at nearly the speed of light and the ATLAS detector measures the properties of the particles produced from these collisions. Due to the high rate of data production, the ATLAS detector utilizes a trigger system to quickly discriminate between potentially interesting events and background events. In many new physics models, the rate of production of two Higgs bosons can be enhanced and hence observable. While participating in a research semester on site at CERN during Fall 2016, I designed a trigger to be highly effective in the search for the signal of the production and subsequent decay of two Higgs bosons. The trigger was evaluated by running on computer simulations of the two Higgs decay signal and a dataset of background processes collected by the ATLAS detector.
Imaging by Raman Microspectroscopy
Abstract: Analytical chemists are interested in developing the methods and instruments used to acquire chemical information. Microscopy and spectroscopy are methods that reveal chemical information based on how light interacts with matter. This presentation focuses on Raman Microspectroscopy; a method that combines the imaging information of microscopy with the vibrational spectral information of Raman spectroscopy. Raman Microspectroscopy is a powerful technique that is providing advancements in the fields of chemistry, biochemistry, biology, materials science, and medicine.
Synthesis of reversible phase transition titanium oxides
Abstract: Heat-storage materials such as liquids and molten salts cannot store heat for long periods due to thermal radiation. Here we report a novel phase transition titanium oxide capable of storing energy and releasing it only upon application of external forces. This room-temperature ceramic phase change responds to light, heat, and current, providing applications both for industrial heat storage as well as sensing and phase-change memory applications.
Optimization of Multiple-Cavity Systems for Dark Matter Axion Searches
Abstract: According to our fundamental theories of particle physics, there can be a violation of the CP symmetry, the combination of charge-conjugation (switching a particle with its antiparticle) and parity (inversion of space) symmetries. However, no known experiments show CP violation of the strong nuclear force -- the so-called “strong CP problem”. One way to resolve this problem, proposed in the 1970s, is the existence of elementary particles called axions. Axions are also of interest in explaining cold dark matter. Thus, the search for axions has gained attention in recent years.
Multiple-cavity systems can serve as a method of detecting the potential existence of the axion. This summer, I worked on an experiment at the Center for Axion Precision Physics that focuses on sweeping for axions in the deBroglie frequency range of 1-4 GHz, which previously had not been explored. Using specialized computer software, I analyzed how the strength of the axion signal in a double Oxygen-Free High Conductive copper-cavity system changed as the coupling of its antennas were altered. As expected, the coupling did not impact the unloaded quality factor of the cavity. Additionally, a cavity was immersed in liquid helium and had an unloaded quality factor three times larger than at room temperature. These results indicate that the unloaded quality factor of a cavity can be increased at lower temperatures, resulting in a larger signal
Magnetic Field Control for Experiments with Ultracold Atomic Sodium Gases
Abstract: In ultra-cold atomic gases, classical collisions between individual atoms are dominated by more exotic interactions, such as "spin-changing" collisions. These interactions are extremely sensitive to magnetic fields. Consequently, it is an important research area is the elimination of background magnetic fields and gradients from the atom trap. In this talk, I will present the results of my 2016 REU experience in the lab of Dr. Arne Schwettmann at Oklahoma University, in particular the creation and implementation of a 3D-printed triaxial Helmholtz arrangement and a stabilized current supply.
Opposite-Sign Vector Boson Scattering with Simulated ATLAS Data
Abstract: The ATLAS experiment on the Large Hadron Collider is a general detector used to study particle behavior at high energies. In particular, we are looking for the scattering of \(W+\) \(W-\) bosons because the interaction is sensitive to Higgs behavior, which is not yet well understood. We determine the best way to pick out this signal by eliminating background events with criteria like particle momentum, energy, and position. Once we have optimized a data analysis routine for this simulated data, we will apply it to the real data and see if there are differences. An unexpected result from the real data would suggest new Higgs properties.
Sonoluminescence and Sonoreactors
Abstract: Ultrasonic waves in a liquid induce acoustic cavitation, which produces rapidly expanding and contracting bubbles. These bubbles are seen to visibly glow, which is the phenomenon that defines sonoluminescence. Though sonoluminescence was discovered in 1934, a reasonable explanation for its mechanism was not put forward until 2002; the mechanism involves the formation of plasma due to the extremely high temperatures inside the bubble. The interaction at the plasma-liquid interface produces chemically useful radicals, so considerable effort has been expended to produce viable “sonoreactors.” In 2013, Y. Iwata et al demonstrated a simple sonoreactor design that used a punctured metal plate with precisely tuned dimensions, position, and hole diameter. In this seminar, I will review the basic phenomenology of sonoluminescence and discuss the recent progress in the field.
Improving the Search for Gravitational Waves from the Coalescence of High Mass Black Hole Binaries
Abstract: Solutions to Einstein’s field equations predict gravitational waves: disturbances in space-time that propagate at the speed of light. Detecting gravitational waves is challenging because the signals are very weak and so a very sensitive instrument is required. The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a pair of detectors that search for these disturbances by looking for small length changes caused by passing gravitational waves. One promising class of sources of gravitational waves is binary black holes. Signals from such sources are searched for in the data from the detectors with an analysis pipeline called gstlal using an advanced form of matched filtering which helps to pull out small signals from a background of noise. In this talk I detail steps taken toward optimizing the gstlal pipeline for Advanced LIGO in the context of binary black hole detection. Specifically, I describe a novel method for the generation of stochastic template banks which is significantly faster than the traditional method and discuss attempts to improve the autocorrelation \(\chi^2\) used to veto glitches in the LIGO data.
Momentum Transport in Plasmas: New Methods in Data Analysis
Abstract: Nuclear fusion promises to be a virtually unlimited, clean source of energy. However, the conditions required to trigger it are extremely difficult to maintain, as they involve confining an extremely energetic plasma long enough for fusion reactions to take place. One of the current confinement schemes is the tokamak, a donut-shaped vessel that uses magnetic fields to confine the plasma to a ring-shaped region. This plasma rotates rapidly, and the rotation rate depends both on distance from the core of the plasma and time. Understanding how the rotation profile evolves is very important for ensuring the stability of the plasma; this understanding stems primarily from momentum transport. However, momentum transport analysis is still incomplete. Previous analysis determined values for relevant quantities locally, one radius at a time; while this worked in some areas, it neglected global effects that might influence the rotation. In order to increase the strength and versatility of this analysis, we have developed a new method for inferring profiles that takes into account all radii at once. We have tested this method and demonstrated its applicability in a wide range of conditions. We have also shown that our approach yields more complete profiles than the local analysis in previously-analyzed data.
Straw Detector Technology and the Search for Neutron-Antineutron Oscillations
Abstract: A current mystery in physics is the baryon asymmetry, or why we observe more matter than antimatter – a problem not explained by Standard Model physics. A neutron oscillating to an antineutron would violate baryon number, which would give us insight to possible mechanisms for baryogensis, the cause of this asymmetry. There are grand unified theory candidates that predict violation of baryon number and the energy scale we observe this violation happening (or not happening) on helps narrow down the possible mechanisms at work.
Like almost all of modern particle physics, we can study neutrons by accelerating them in a particle detector and observing their behavior. The beam of neutrons hits an annihilation target and reflects off, going through the tracking components of the detector before the calorimeter. We are studying straws used in the tracker device. As charged particles move through the straw, they send a signal to a wire in the center. We can reconstruct the particle’s trajectory based on the time it took for the particles to be detected by the straw. To make this a more robust calculation and evaluate the efficiency of the straws, we compare the data of straws near each other to see if they all tracked the same trajectory By analyzing the data of a preliminary run, we can test the efficiency of the straws as a tool for particle detectors.
AdS/CFT in Spatially Anisotropic Backgrounds
Abstract: The AdS/CFT correspondence is a powerful result from string theory relating quantum field theories in a d-dimensions to dual gravitational models in d+1-dimensions. The correspondence is especially useful in the study of strongly-coupled quantum field theories, where conventional techniques are insufficient. This talk reviews the background and motivation for the application of the AdS/CFT correspondence to condensed matter systems and presents results on the behavior of massive scalar fields in spatially anisotropic background spacetimes.
Abstract: For undergraduate physics majors preparing to apply to grad school, the admissions process can be opaque and intimidating. Figuring out what admissions committees want is difficult, and advice is either sparse or overwhelming. In this talk, I’ll attempt to shed some light on this daunting process. I’ll present a combination of advice I’ve found helpful, as well as reflections on my own experiences with graduate school admissions. Results may vary.
Determination of Stable Circumbinary Orbits through Numerical Simulation
Abstract: The University Physics Competition is an annual physics competition that lasts 48 hours. Students participating in the competition construct a solution to one of two problems provided and submit the solution for evaluation. Problem A of the 2014 competition asks students to determine the stable orbits of a planet in a binary star system with a one solar mass and a one-half solar mass star. Over half of the "stars" in the Milky Way are actually multiple-star systems. New observational data has shown that, contrary to long-held expectation, exoplanets may undergo formation and stable orbits in these multiple-star systems. These systems must be included in searches for exoplanets, and an understanding of orbital dynamics of exoplanets in a binary star system is necessary to conduct efficient searches. We solved for the motion of the binary star system given and simulated trajectories of planets with a wide range of initial positions and velocities. Through simulation of this restricted three-body problem, we find constraints on stability conditions for exoplanets in this system. In particular, we find a range of interesting P-type orbits and are able to rule out the possibility of stable S-type orbits in this binary system.
Lorentz-Violating Electromagnetostatics and a Modified Multipole Expansion
Abstract: The Standard-Model Extension (SME) is a general effective field theory for Lorentz and CPT violation incorporating both the Standard Model and General Relativity. The SME provides a framework for experimental searches for Lorentz violation and for the investigation of new physics. In the static limit of Lorentz-violating electrodynamics, unusual mixing of electrostatic and magnetostatic effects occur. This talk investigates some aspects of Lorentz-violating electromagnetostatics, emphasizing modifications to multipole expansions of conventional electrostatics.
An Introduction to LHCb and a Precision Test of the Standard Model
Abstract: The LHCb experiment aims to explore the universe's observed matter-antimatter asymmetry through searches for CP violation in decays of particles containing bottom quarks. This is a promising direction for searches for physics beyond the Standard Model, and LHCb will collect and study the world's largest sample of such decays. These studies require precise Standard Model predictions of b-hadron decay rates, which are calculated using the Heavy Quark Effective Theory. Precision tests are necessary to verify the validity of this predictive model. In this talk I will introduce the LHCb experiment and the physics it studies. In addition, I will give an overview of the work I conducted this past summer on a precision measurement of the lifetime difference of B0 and Bs0 mesons.
Classical-Physics Examples for Standard-Model Extension Finsler Structures
Abstract: The Standard Model Extension (SME) is a general effective field theory for Lorentz and CPT violation incorporating both the Standard Model and General Relativity that may be used in experimental tests for Lorentz violation and the investigation of new physics. The addition of Lorentz- and CPT-violating effects in the SME may require more generalized mathematical techniques than used in General Relativity and the Standard Model. This talk will present motivation for the SME and interest in spacetime symmetries, discuss new geometries of interest, and present research on developing understanding of these geometries through classical-physics analogues.
Machine Learning in Particle Physics and Other Applications
Abstract: By their very nature, particle physics detector experiments tend to collect huge amounts of data, describing upwards of billions of physical events. Any particular interesting phenomenon, however, will occur in only a small portion of these events, requiring the isolation of a proportionally tiny signal sample from an immense background. This raises a question of fundamental importance to any such data analysis: How can we select a signal sample with the size and purity necessary to observe the phenomena of interest using only the imperfect data our detector provides? Many particle physics experiments have begun approaching this problem using machine learning. In this talk, I will provide some background on machine learning and demonstrate its application in particle physics experiments. In addition, I will demonstrate other interesting applications of machine learning outside of physics.
Computational Methods in Physics
Abstract: It is becoming more and more common to model problems and physical situations using computer simulations. In addition, all modern data analysis relies on the use of computers to process large sets of data. In this talk, I will discuss some basic methods for efficiently computing beginning with some basic examples and algorithms used in data processing. More sophisticated techniques will be briefly discussed and to conclude, a simulation of Brownian motion will be shown to illustrate one of the powerful uses of computers: stochastic simulation.
A Brief Introduction to Quantum Computing
Abstract: Moore's Law predicts that within twenty years transistors will be the size of single atoms. Will computing be less interesting after that? Quite the contrary. In this talk I will discuss quantum computing, a fundamentally different way of processing information. This exciting and rapidly developing new paradigm promises to greatly improve our understanding of quantum systems (Richard Feynman himself was one of the first to recognize this) and has other interesting consequences for the way we solve problems. Examples I'll discuss include one algorithm that will render current internet security protocols insecure, and another that allows searching an unsorted database in time that is sub-linear (!) in the number of entries. I'll give a concrete example of how quantum algorithms can solve certain problems faster than any possible classical algorithm. Finally, I'll discuss attempts at actually building a quantum computer and how such efforts are at the core of a “third quantum revolution.”
Physics of cancer
Abstract: Given the vast complexity of cancer, it should be no surprise that there is a need for physical scientists to help inform cancer models. In this talk, I will outline the applications of physics to model cancer on multiple biological levels, with a particular emphasis on the cellular/tissue level. Physics has been used extensively in radiation treatment for cancer, but only recently have scientists turned to physical theory to explain cancer. In late 2008, The National Cancer Institute (NCI) decided to support 12 Physical Sciences in Oncology Centers and has spurred breakthroughs in understanding and controlling cancer. By leveraging traditionally physical concepts including fluid mechanics, statistical mechanics, adhesion, Monte Carlo methods and even chaos theory, we can bring new insight to modeling the complexity of cancer.
The Story of Chaos: A historically-guided introduction to the principles, icons, and applications of chaos theory
Abstract: Chaos theory has gained popularity in recent years for its relevance to problems in nonlinear dynamics. However, in reality, chaotic behavior in deterministic systems has puzzled and intrigued physicists for centuries. In this seminar we explore chaos theory by beginning, of all places, at the end. By considering the implications of a seemingly simple question posed by Mandelbrot, we first aim to develop an intuition for self-similarity and fractal dimensions. Then, we return to the impetus for the development of chaos theory: the intractable n-body problem. After working through the essential elements of Poincaré and Lyapunov's approach to the problem, we move on to consider Lorenz's contributions to the modern resurgence of chaos theory. We then illustrate the emergence of chaotic behavior in simple systems and conclude with the principles of period doubling and universality. By utilizing Mathematica's powerful software and presentation platform, we provide a visually engaging introduction to chaos theory which aims to appeal to newcomers and veterans alike.
S-P wave interference in K+K−photoproduction from CLAS
Abstract: Photoproduction has only recently become a powerful tool in investigations of meson spectroscopy. The data samples from the CLAS g11 run at JLab exceed the existing sets by at least an order of magnitude, thus allowing for a comprehensive study. For effective di-kaon masses near 1 GeV, the K+K− photoproduction cross section is dominated by the \(\phi\)(1020) resonance in the P-wave. However, a careful analysis of the kaon angular distributions in the KK center of mass reveals asymmetries that can be attributed to an S-wave contribution from the decay of the scalar resonances f0(980) and a0(980). These effects show up as interference patterns in angular moments. The moments characterizing these asymmetries are used to extract information about S-P wave interference through partial wave amplitudes. In this talk, I will discuss the fundamentals of partial wave analysis, nontrivial ambiguities in partial wave amplitudes, and general amplitude analysis techniques.
Fabrication and Characterization of Nano-structures
Abstract: I will present an overview of the fabrication and characterization of nanostructured materials. Basic fabrication processes will be visited including deposition, masking, and etching. Current research in characterization of certain nanostructures geometric dependent properties will be discussed. The presentation will conclude with a discussion of various probing techniques currently in use including Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM) and Scanning Electrochemical Microscopy (SECM).
Physics in Chemistry: An Introduction to Electronic Structure Theory and Molecular Dynamics
Abstract: Given the resounding implications of quantum mechanics, it is only natural that the subject permeates the foundations of modern chemistry. In this seminar, we explore the physics behind the theory of quantum chemistry and motivate the theory by briefly addressing its applications. The talk will begin with a discussion of molecular dynamics methodologies and the Born-Oppenheimer approximation. We then quickly develop the basic machinery of electronic structure theory and subsequently discuss the Hartree-Fock approximation. Finally, we conclude with an introduction to post-Hartree-Fock methods, including Configure Interaction (CI) methods and Moller-Plesset Perturbation theory.
Symmetry in Physical Law
Abstract: The utility of symmetry in physics is well known to even freshman-level students in simplifying the solutions of some problems. The invariance of physical law under coordinate transformation is another, deeper manifestation of symmetry in physics. In this seminar, we give the shortest-ever introduction to group theory, and go on to explain different aspects of symmetry in physics such as global/local and internal/external symmetry, continuity/discreteness, and the characterization of different physical examples in this way. We also discuss CPT (charge-parity-time) symmetry and conservation laws as consequences of symmetry in physical laws. Perhaps even more important than the symmetry laws themselves is broken symmetry, in fundamental laws (CPT) as well as in macroscopic objects. Finally, we introduce the phenomenon of "emergence" which is the exhibition by a system of characteristics which the fundamental constituents of the system do not possess.
Design and Construction of a Xenon Gas-handling System for Studying Backgrounds in Neutrino-less Double Beta Decay Experiments
Abstract: The enigmatic and evasive nature of neutrinos has perplexed particle physicists since they were first theorized in 1930. Although discovered in 1956, it was not until 12 years ago that physicists realized that these once-considered-massless particles did indeed have mass. Neutrinos are significantly lighter than other known massive particles, which leads one to question if neutrinos follow a different behavior. It is also true that the structure of the universe depends on the value of its absolute mass, yet that value still eludes today’s brightest minds.
One way to measure the absolute mass of the neutrino is to search for a rare process called neutrino-less double beta decay. The Enriched Xenon Observatory (EXO) for double beta decay searches for this process using the isotope of 136Xe. Observing this decay is like looking for a needle in a haystack, or, in this case, a very narrow peak in an energy spectrum that is full of many peaks, both narrow and wide; it is imperative that the experiment can resolve everything that contributes to the spectrum in order to claim they see a signal for the neutrino-less double beta decay at the right energy value.
Particles known as gamma rays can contribute to this spectrum and are produced at various energies by neutrons near the experiment that interact with the Xenon. In order to look for unknown gamma-ray backgrounds, we are constructing a gas-handling system for a Xenon target to be used in a neutron beam-line at Los Alamos National Laboratory, where we will be measuring the gamma rays that come from these interactions to look for any that might appear near the energy of the double beta decay. My work entailed design and constructions of the gas-handling system for installation in Los Alamos at the end of 2012.
Research for this project was supported by a grant from the Indiana University Faculty Research Support Program and the National Science Foundation.
Scaling behavior in neuronal networks
Abstract: Physicists have (relatively) recently begun to use methods and models from physics to describe biological systems. One such application has been the investigation of whether networks of neurons operate at a critical point and the characterization of their critical behavior. I will briefly summarize the background and motivation for this approach, then I will discuss recent work that robustly demonstrates scale invariance (a characteristic feature of critical phenomena) in neuronal recordings.
Recent analysis of a new class of proton correlation functions in Lattice QCD
Abstract: Lattice QCD calculations have become increasingly more accurate due in large part to the refinement of the computational methods needed to calculate the correlation functions required for phenomenology. In this talk, I will discuss recent analysis of a new class of lattice QCD correlation functions for the proton in order, created to better calculate the ground and excited state masses. This new class is derived from a known class that works well for small volume. Previously efficiency deteriorates for larger volumes. For this reason we focus our study on the volume dependence of noise and the contamination from excited states. Our results indicate as the volume grows, noise is reduced, i.e. our method behaves better as volume grows (in our volume range). In addition the contamination from excited states becomes smaller as volume grows. Overall this method seems to scale well. This material is based upon work supported by the National Science Foundation under Grant No. PHY-1156997.
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