Physics & Astronomy News
LIGO Detects Gravitational Waves for Third Time
The Laser Interferometer Gravitational-wave Observatory, or LIGO, has made a third detection of gravitational waves, which are ripples in space and time, demonstrating that a new window in astronomy has been firmly opened. As was the case with the first two detections, the waves were generated when two black holes collided to form a larger black hole.
Kristina Launey Receives Socolofsky Award
Assistant Professor of Physics & Astronomy Kristina Launey is the recipient of the 2017 Dr. Marion D. “Soc” Socolofsky Award for Teaching Excellence. Launey was presented with the award during a surprise visit to her classroom earlier this month by College of Science Dean Cynthia Peterson and Chair of the LSU Department of Physics & Astronomy John DiTusa.
LSU Physicist Ivan Agullo Awarded Top Gravity Research Prize
LSU Department of Physics & Astronomy Assistant Professor Ivan Agullo has received the first place award from the Gravity Research Foundation for his essay titled "Gravity and Handedness of Photons," which he co-authored with his colleagues Adrian del Rio and Jose Navarro-Salas, professors at Spain's Universidad de Valencia.
"Plan a future of science that is best for China” An interview with Dr. Earl Plummer, winner of the 2016 CAS Award for international scientific cooperation
In this interview, Dr. Plummer shared his decades-long experiences of working with CAS, and his insights on the research future in China.
The Most Mysterious Star in the Galaxy
It has been dubbed the most mysterious star in the galaxy. The star, more than 1,200 light-years away in the constellation Cygnus the Swan, flickers and dims in a way never seen before.
Spring 2017 Physics & Astronomy Graduates
On Friday, December 16, LSU Physics & Astronomy welcomed 4 new PhD, 1 MS and 10 BS graduates who conferred their degrees at the Marvavich Assembly Center and Maddox Fieldhouse. Kundan Kadam, PhD (advisor: Dr. Geoffrey Clayton ) Jiayum Pan, PhD (advisor: Dr. Rongying Jin) Mohammad Saghayezhian, PhD (advisors: Dr. Ward Plummer and Dr. Jiandi Zhang ) Marissa Walker, PhD (advisor: Dr. Gabriela González ) Anthony Ramon Davila, MS Daniel Joseph DiMarco, MS Kyle Joerres, MS Brandon Michael Luckett, MS William Craig Jones, BS Sean Michael Laughlin, BS Lucas Chad Lavoie, BS Simon Gabriel Lorenzo, BS Dylan Beckley Ottea, BS Patrick Lee Quebedeaux, BS Irene Vargas-Salazar, BS
“Energy Calibration of CALET Onboard the International Space Station”, Y. Asaoka, N. Cannady, M.L. Cherry, T.G. Guzik, A. Javaid, J.P. Wefel et al., Astroparticle Physics 91, 1 (2017)
In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units.
Alumnus Donald Kniffen named to College of Science Hall of Distinction
The LSU College of Science inducted four exceptional individuals into the Hall of Distinction on March 31, 2017, among them Donald Kniffen, 1959 LSU Physics & Astronomy alumnus and NASA research scientist. Kniffen, a magna cum laude graduate, is an accomplished astrophysicist and more than 40-year veteran of the NASA space program. He has been a leader in the national and international high-energy astrophysics community, and is one of the scientists who developed the field of high-energy gamma-ray astronomy. Gamma rays are emitted characteristically by the most energetic and exotic objects in the Universe, and gamma-ray astronomy is now one of the highest priority fields of astronomy.
Gabriela González Elected to the National Academy of Sciences
The National Academy of Sciences announced today that LSU Department of Physics & Astronomy Professor Gabriela González has been elected as a member to the academy. González is one of the 84 new members recognized for her distinguished and continuing achievements in original research. She is an experimental physicist with the Laser Interferometer Gravitational-wave Observatory, or LIGO, who contributed to the detection of gravitational waves in 2015 predicted by Albert Einstein’s Theory of General Relativity.
Kirby Awarded Economic Development Assistantship to Study iMQC MRI to Help Detect Brain Tumors and Fight Obesity
Krystal Kirby, a third-year PhD student working under Dr. Owen Carmichael at LSU’s Pennington Biomedical Research Center, has been awarded an Economic Development Assistantship by the LSU Graduate School. Kirby is enrolled in the medical physics program in the Department of Physics & Astronomy, and is currently performing her research at the Pennington Biomedical’s Imaging Facility, which was opened in 2014.
"Primordial power spectra for scalar perturbations in loop quantum cosmology" by Daniel Martín de Blasa and Javier Olmedob, Journal of Cosmology and Astroparticle Physics, Volume 2016, June 2016
We provide the power spectrum of small scalar perturbations propagating in an inflationary scenario within loop quantum cosmology. We consider the hybrid quantization approach applied to a Friedmann-Robertson-Walker spacetime with flat spatial sections coupled to a massive scalar field. We study the quantum dynamics of scalar perturbations on an effective background within this hybrid approach. We consider in our study adiabatic states of different orders. For them, we find that the hybrid quantization is in good agreement with the predictions of the dressed metric approach. We also propose an initial vacuum state for the perturbations, and compute the primordial and the anisotropy power spectrum in order to qualitatively compare with the current observations of Planck mission. We find that our vacuum state is in good agreement with them, showing a suppression of the power spectrum for large scale anisotropies. We compare with other choices already studied in the literature.
"Observations of V0332+53 during the 2015 Outburst using Fermi/GBM, MAXI, Swift, and INTEGRAL" by Zach Baum, Mike Cherry, and James Rodi, Monthly Not. Royal Astron. Soc. 467, 4424 (2017)
We present the light curves, spectra and hardness-intensity diagram (HID) of the high-mass X-ray binary V0332+53 using Fermi/GBM, MAXI, Swift/BAT and INTEGRAL through its 2015 Type II outburst. We observe characteristic features in the X-ray emission (2-50 keV) due to periastron passages, the dynamical time-scale of the accretion disc, and changes within the accretion column between a radiation-dominated flow and a flow dominated by Coulomb interactions. Based on the HID and the light curves, the critical luminosity is observed to decrease by ∼5 per cent to 7 per cent during the outburst, signalling a decrease in the magnetic field.
2017 Annual Physics & Astronomy Awards Ceremony
Congratulations to the award recipients at the Annual Physics & Astronomy Awards Ceremony College of Science Outstanding Junior – Derek Walker Tiger Athletic Foundation Undergraduate Teaching Award- Dalgis Mesa Keen-Morris Award – Simon Lorenzo Keen-Morris Award – Irene Vargas-Salazar Student Scholarships awarded by the College of Science: Margarite Laborde - Willie Belle Shockley Scholarship Chris Abadie – Annie and Willie Austin Scholarship Rory Bentley – Frank J. and Phyllis Heroy Scholarship Zach Bradshaw - Tiger Athletic Foundation Scholarship Megan Chesal - Tiger Athletic Foundation Scholarship Jonah Hoffman - Tiger Athletic Foundation Scholarship Departmental Awards Dept. Undergraduate Research Awards Ivan Hidrovo – working with Joyoni Dey Jonah Hoffmann – working with Mike Cherry Sean Laughlin – working with Kristina Launey Graduate Teaching Awards – Chris Greenley; Tyler Ellis; and Zhihao Xiao. Undergraduate Learning Assistant – Derek Walker Graduate Faculty Teaching – Jonathan Dowling Undergraduate Faculty Teaching – Ivan Agullo
Lorenzo and Olivier Receive NSF Graduate Research Fellowships
The National Science Foundation, or NSF has recognized Simón Gabriel Lorenzo, of Baton Rouge, La. and Andrew Paul Olivier, of Houma, La., as 2017 Graduate Research Fellows. NSF named 2,000 individuals as this year's recipients of the graduate fellow awards, which provide three years of financial support within a five-year fellowship period - a $34,000 annual stipend and $12,000 cost-of-education allowance to the graduate institution. That support is for graduate study that leads to a research-based master's or doctoral degree in STEM fields, STEM education and social sciences.
Six LSU Students Receive NRC Scholarship in Health Physics
A recent grant from the U.S. Nuclear Regulatory Commission (NRC) has been established at LSU to support undergraduate students to explore careers in the radiation sciences through the field of health physics. LSU's Department of Physics & Astronomy has announced the first recipients of the scholarship program in health physics: • Joshua Campbell, chemical engineering • Daniel DiMarco, physics • Angelle Leger, mechanical engineering • Brandon Luckett, physics • Devin Manning, chemical engineering • Gregory Martini, chemical engineering
Alison Dreyfuss Receives U.S. Department of Energy Graduate Research Award
The U.S. Department of Energy Office of Science Graduate Student Research, or SCGSR, has awarded doctoral candidate Alison Dreyfuss of Keene, N.H. with funding to conduct part of her Ph.D. thesis research at Lawrence Livermore National Laboratory. The award will support six months of collaborative research with LLNL physicist Jutta Escher, who is also an LSU alumna. Dreyfuss will work on a project titled "Understanding nucleosynthesis from a symmetry-informed ab initio perspective."
"Cosmological dynamics in spin-foam loop quantum cosmology: challenges and prospects" by David A Craig and Parampreet Singh. Class. Quantum Grav. 34 074001 (2017)
We explore the structure of the spin foam-like vertex expansion in loop quantum cosmology and discuss properties of the corresponding amplitudes, with the aim of elucidating some of the expansion's useful properties and features. We find that the expansion is best suited for consideration of conceptual questions and for investigating short-time, highly quantum behavior. In order to study dynamics at cosmological scales, the expansion must be carried to very high order, limiting its direct utility as a calculational tool for such questions. Conversely, it is unclear that the expansion can be truncated at finite order in a controlled manner.
"Numerical simulations of loop quantum Bianchi-I spacetimes " by Peter Diener, Anton Joe, Miguel Megevand and Parampreet Singh. Class. Quantum Grav. 34 094004 (2017)
Due to the numerical complexities of studying evolution in an anisotropic quantum spacetime, in comparison to the isotropic models, the physics of loop quantized anisotropic models has remained largely unexplored. In particular, robustness of bounce and the validity of effective dynamics have so far not been established. Our analysis fills these gaps for the case of vacuum Bianchi-I spacetime. To efficiently solve the quantum Hamiltonian constraint we perform an implementation of the Cactus framework which is conventionally used for applications in numerical relativity. Using high performance computing, numerical simulations for a large number of initial states with a wide variety of fluctuations are performed. Big bang singularity is found to be replaced by anisotropic bounces for all the cases. We find that for initial states which are sharply peaked at the late times in the classical regime and bounce at a mean volume much greater than the Planck volume, effective dynamics is an excellent approximation to the underlying quantum dynamics. Departures of the effective dynamics from the quantum evolution appear for the states probing deep Planck volumes. A detailed analysis of the behavior of this departure reveals a non-monotonic and subtle dependence on fluctuations of the initial states. We find that effective dynamics in almost all of the cases underestimates the volume and hence overestimates the curvature at the bounce, a result in synergy with earlier findings in the isotropic case. The expansion and shear scalars are found to be bounded throughout the evolution.
Gabriela González Elected to the American Academy of Arts and Sciences
Professor Gabriela González is among some of the world’s most accomplished scholars, scientists, writers, artists as well as civic, business and philanthropic leaders elected to the American Academy of Arts and Sciences. The academy announced today its 228 newly elected members for 2017. The list of the 237th class of new members is available at www.amacad.org/members.
Research led by Ivan Agullo Discovers Hidden Aspects of Electrodynamics - Discovery may impact the study of the birth of the universe
Radio waves, microwaves and even light itself are all made of electric and magnetic fields. The classical theory of electromagnetism was completed in the 1860s by James Clerk Maxwell. At the time, Maxwell’s theory was revolutionary, and provided a unified framework to understand electricity, magnetism and optics. Now, new research led by LSU Department of Physics & Astronomy Assistant Professor Ivan Agullo, with colleagues from the Universidad de Valencia, Spain, advances knowledge of this theory. Their recent discoveries have been published in Physical Review Letters. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.111301. This research is supported by the National Science Foundation grants PHY-1403943 and PHY-1552603.