Session C06: Undergraduate Research III

Two-Decade Monitoring of MWC349 in Optical and Radio

TMaria Mitchell Observatory (MMO) has completed the two-decade long monitoring of MWC 349 in the optical and radio domains. This poster presents the new results obtained by optical photometry with broad and narrow band filters and observations of the variability in the masing H30 radio line during the observational season of 2017. The H30 emission arises in the circumstellar disk of the MWC 349A component of the visual double star (with 2.4 arcsec separation between the A and B components). Variable optical emission is also believed to be due to star A. In combination with earlier MMO optical observations, we confirmed the previously known quasi-period of ~230 days and detected a second of ~700 days. One of the most interesting results of radio monitoring is the long-term variability of the systemic radial velocity of star A, as determined through averaging the radial velocities of the two masing peaks arising in the circumstellar disk. E.T. completed this project as a 2017 MMO NSF REU intern and would like to thank the other interns for their help in conducting the optical observations. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.   

Search For Type IA Supernova NUV-Optical Subclasses

Type Ia Supernovas (SNIa) are very bright standardizable candles that can be used to measure cosmological parameters. A recent observation by Milne and collaborators claims that there are two classes of SNIa distinguished by their peak brightness in the ultraviolet, and that cosmological parameters measured with SNIa are severely biased unless the two classes are treated separately. We search for evidence for two classes of SNIa in archived SNIa data from the Sloan Digital Sky Survey (SDSS) and the SuperNova Legacy Survey (SNLS) comparing to a model of the Milne claim and a model with a single, broad distribution of SNIa peak ultraviolet brightnesses. The SNLS data decisively supports a single single class of SNIa while the SDSS data is unable to distinguish between the two models. We see no evidence in support of the Milne and collaborators claim for two classes of SNIa.   

Numerical Methods for Determining Eigenenergies and Tunneling Rates in One-Dimensional Quantum Wells

Astronomers have long been interested in the beginning stages of star formation in cold regions of the universe. It is well established that at those low temperatures, Hydrogen atoms are the ones that are most involved in diffusive mechanisms. However, recent studies have found that diffusion of heavier particles such as oxygen can also be effective. Here we present a theoretical investigation of the efficient diffusion of oxygen-isotopes via quantum tunneling through a one-dimensional subsequent potential. Oxygen-16, oxygen-17, and oxygen-18, which were considered as point particles, were originally confined in a one-dimensional finite potential quantum well and were expected to tunnel through a finite potential barrier. This presumption was tested using MATLAB, through which graphical and numerical solutions were computed in order to obtain eigenenergies for each isotope. Results show that oxygen isotopes that diffused through a finite quantum well having a set potential height of 0.07eV and a width of 0.7Å and that tunneled through a subsequent finite barrier with a set potential height of Vo and a barrier width ranging from 0.1Å to 3Å revealed mass-independent isotopic effects, which were first discovered experimentally in 1983 by Mark H. Thiemens and Heidenreich.   

Floquet Formalism and Perturbation Theory in the Low-Frequency Limit

Quantum mechanics is one of the most prominent theories in physics today. However, despite being wildly useful, there exist very few exactly solvable quantum problems. Because of this, physicists rely very heavily on theories which provide approximate solutions to those problems which are not exactly solvable, in particulate within the framework of perturbation theory. In this talk, I present a perturbation theory for the low-frequency limit of a periodically-driven quantum system. I compare the corrections to the Rabi problem found using this method to the expansion of its exact solutions to determine the accuracy of the method. I then apply the method to the two-spin Rabi system. I also discuss other extensions and applications of this work to many-body periodically driven systems.   

Auxiliary Conditions To The Euler-Lagrange Equations For A New Class Of Non-Standard Lagrangians

A new class of non-standard Lagrangians that explicitly depend on the special functions of mathematical physics is discovered
and this requires adding some auxiliary conditions to the Euler-Lagrange equations. Several examples with applications of the
new non-standard Lagrangians are presented and discussed. Moreover, the relationships between the obtained results and Lie
algebras and Lie groups are also addressed.   

Exploring Dimensional Crossover in Heisenberg Magnets using RIXS Spectroscopy

Resonant Inelastic X-ray scattering (RIXS) is a novel experimental technique to characterize the properties of magnetic materials. The goal of this research is to theoretically investigate the effect of spatial anisotropy and next-nearest neighbor interaction on the multiple peak location of the bimagnon RIXS spectrum. Utilizing a Green function approach within the Bethe-Salpeter scheme we wrote a python code to simulate the indirect RIXS spectrum. Using a spin wave theory magnetization phase diagram and the associated spatial anisotropy parameter (zeta) and next nearest neighbor interaction parameter (eta) we notice that the RIXS spectrum can develop multiple peaks. By fitting the location of the peaks we observe that a pattern emerges in how these peaks are affected by interaction. In the vast majority of the parameter space the peak of a fixed zeta with increasing eta combination shifts downward in frequency with each consecutive increase in eta. However, there are a couple of parameters where an upshift was observed. Based on our fits of the peak location we conclude that the pattern follows either a linear or non-linear dependence on eta for a fixed zeta. We also draw connections to the peak movement and dimensional crossover in quantum Heisenberg magnets.   

Methods of Muon Detection and an Analysis of Cosmic Rays.

Presenting the First results of an array of cosmic ray detectors assembled by a team of undergraduate students at EVC, using guidelines prescribed by the well established LBL Cosmic Ray Project. The objectives of this project are to explore different techniques and methods of collecting cosmic rays, create opportunities for hands-on experimental science for college students and initiate a culture of S.T.E.M. undergraduate research across Community Colleges. Cosmic rays are measured using plastic scintillators mounted to high voltage photomultiplier detectors and Geiger counters. Assembly of logic coincidence circuits and event displays circuits were used to test, process, and store data using an Arduino UNO micro-controller. At this conference meeting, experimental results and analysis would be presented, as well as plans utilizing cosmic ray detectors as a vehicle for outreach to increase greater awareness of doing hands-on science in local communities.   

Cosmic Ray Water Cherenkov Detector

Cosmic rays are high energy particles that travel through space and shower Earth. Cherenkov radiation consists of electromagnetic radiation that is produced when remnants of secondary cosmic rays travel through earth’s atmosphere and surpass the speed of light in a material medium. Quantitative and qualitative analysis of cherenkov radiation can help determine the cosmic ray’s energy and speed. Our research project was to create simple and reliable Cherenkov detectors for use to outreach to high school STEM students. For this, we used two modified thermos bottles with distilled water as the medium to produce Cherenkov radiation. To observe the Cherenkov radiation from cosmic rays, two Photomultiplier detectors (PMT) were used and each was submerged in a thermos bottle and covered with light tight foils. Extensive evaluations were done for various placements of the detectors in both the vertical and the horizontal directions to obtain coincidence cosmic ray events. Results from our experiments indicated that the thermos detectors were detecting Cherenkov radiation produced by cosmic particles.   

Speed of Cosmic Ray Muon Using Silicon Photomultipliers

Recently, the silicon photomultiplier (SiPM) has attracted considerable attention as a possible replacement for the conventional photomultiplier detector (PMT). To realize the practicality of the SiPM detectors, we developed a 4-fold coincidence experiment to measure the speed of the cosmic ray muons. Moreover, cosmic rays are highly energetic atomic nuclei mainly originating outside the Solar System. After striking the Earth’s atmosphere, cosmic rays are broken into different particles, one of which is the muon. Furthermore, our experimental apparatus consisted of a coincidence setup, a digitizer, and two pairs of cosmic ray detectors involving SiPMs and PMTs. The distance between the two pairs of detectors were periodically altered to determine the arrival time difference between them in order to accumulate time histograms with 3000 coincidence events. Detailed data analysis was conducted using the CERN software package Physics Analysis Workstation (PAW) in a Linux-based operating system. Utilizing the data for the distance and time difference, we were able to measure the speed of the cosmic ray muons.   

Background Studies for an Accelerator-Based Dark Matter Search

The unknown composition of dark matter has always been one of the most intriguing problems in physics. Absence of theoretical and experimental support for Weakly Interacting Massive Particle (WIMP) has focused attention to another dark matter candidate, Light Dark Matter at Accelerators (LDMA). The Directional Recoil Identification From Tracks (DRIFT) project has developed highly sensitive detectors to detect the directionally sensitive ionization created by recoils, an ideal detector for low energy recoils by LDMA. Neutron recoils due to cosmic-ray induced muons and neutrons are one of the most important backgrounds in DRIFT. We have been exploring the backgrounds in DRIFT-IIf, the current detector, under different shielding conditions, including concrete building structures and outdoor sites. Experiments are compared with simulations on GEANT4. Our results show that DRIFT is only sensitive to neutron recoils despite large muon and gamma backgrounds from cosmic rays on the surface. Neutron recoil results will be presented for a detector unshielded, under various thickness of concrete and a lead shield exposed to cosmic rays at the surface.   

Infrared Response of a Quasi-Crystalline Filter

The cosmic microwave background (CMB) is the left over radiation from the Big Bang. Studying this faint microwave signature gives insight into the conditions of the early universe. In order to make precision measurements of the CMB polarization, cryogenic detectors maintained at ~0.1 Kelvin are needed to operate the detectors. Background infrared radiation can warm the instrument and degrade its performance. This thermal radiation can be mitigated by using a series of infrared blocking filters. Traditionally, infrared metal mesh filters consist of several layers of a translationally symmetric tiling (e.g. squares or hexagons) are used to block radiation in large apertures. This approach can lead to diffraction at large angles, which can create a pattern in the angular response. This decreases the angular resolution and beam symmetry, which is vital for polarimetry measurements. This study uses a rotationally symmetric tilling of pentagons which cannot be tiled in two dimensional translational space, also known as a non-periodic quasi-crystal. The quasi-crystalline filter has been fully designed and is awaiting fabrication.