On Friday, May 11, LSU Physics & Astronomy welcomed 3 new PhD, 2 MS and 14 BS graduates who received their diplomas at the Pete Maravich Assembly Center and Maddox Fieldhouse.
2018 University Distinguished Faculty Awards and Annual Physics & Astronomy Awards
LSU's Department of Physics & Astronomy has announced Rebecca DiTusa and Khang Pham as recipients of the NRC scholarship program in health physics. A grant from the U.S. Nuclear Regulatory Commission (NRC) was established at LSU in 2017 supporting undergraduate students to explore careers in the radiation sciences through the field of health physics.
Rainer Weiss, 2017 Nobel Laureate in Physics, MIT Physics Professor Emeritus, and LSU adjunct professor in physics and astronomy, will serve as the keynote speaker for the LSU College of Science spring ceremony, Friday, May 11 at 12 p.m. in Maddox Field House.
Emeritus Boyd Professor Dr. Robert O'Connell is originally from Ireland and received his undergraduate degree from the National University of Ireland Galway, which also awarded him a doctorate of science degree later on. After working four years as a telecommunications engineer, he came to the US in 1958 and got his Ph.D. in theoretical physics from the University of Notre Dame. In his 53-year career at LSU, Dr. O'Connell has made countless contributions to many areas of physics and astronomy.
For more than 30 years, the Astronaut Scholarship Foundation has supported hundreds of top performing students pursuing degrees in science, technology, engineering or mathematics. This year, LSU physics majors Rory Bentley and Harvey Shows are among the top performing scholars to receive the ASF award.
Dowling and collaborators have been awarded more than $7 million from the U.S. Army Research Office to develop quantum technologies related to sensing. Their recently received grant titled, “Quantum control based on real-time environment analysis by spectator qubits,” is funded for three years, with the possibility of a two-year extension for a total of $7.05 million. The purpose of the grant is to develop feedback and control techniques on quantum systems that will be used to improve the performance of quantum computers and sensors.
We present a theoretical investigation of charge migration following strong-field ionization in a multielectron system. We study a model homonuclear molecule with two electrons, each restricted to one dimension ( 1 + 1 D ), interacting with a strong, static electric field. We show that in this system charge migration results from the interplay between multiple ionization channels that overlap in space, creating a coherent electron-hole wave packet in the cation. We also find that, in our case, charge migration following the first ionization manifests as a modulation of the subsequent double-ionization signal. We derive a parametrized semiclassical model from the full multielectron system and we discuss the importance of the choice of cation electronic-structure basis for the efficacy of the semiclassical representation. We use the ab initio solution of the full 1 + 1 D system as a reference for the qualitative and quantitative results of the parametrized semiclassical model. We discuss the extension of our model to long-wavelength time-dependent fields with full-dimension, many-electron targets.
We extend the phenomenology of loop quantum cosmology (LQC) to second order in perturbations. Our motivation is twofold. On the one hand, since LQC predicts a cosmic bounce that takes place at the Planck scale, the second order contributions could be large enough to jeopardize the validity of the perturbative expansion on which previous results rest. On the other hand, the upper bounds on primordial non-Gaussianity obtained by the Planck Collaboration are expected to play a significant role on explorations of the LQC phenomenology. We find that the bounce in LQC produces an enhancement of non Gaussianity of several orders of magnitude, on length scales that were larger than the curvature radius at the bounce. Nonetheless, we find that one can still rely on the perturbative expansion to make predictions about primordial perturbations. We discuss the consequences of our results for LQC and its predictions for the cosmic microwave background.
Taddei PJ, Khater N, Youssef B, Howell RM, Jalbout W, Zhang R, Geara FB, Giebeler A, Mahajan A, Mirkovic D, Newhauser WD. Low- and middle-income countries can reduce risks of subsequent neoplasms by referring pediatric craniospinal cases to centralized proton treatment centers. Biomed. Phys. Eng. Express. 4 025029 (2018).
LSU College of Science and Roger Hadfield Ogden Honors College sophomore Corey Matyas has been named a 2018 Goldwater Scholar. Matyas, a native of Dahlonega, Ga., was nominated through an internal university process earlier in the year. A list of winners was released on Friday, March 30.
The 2018 SEC Faculty Achievement Award selection from LSU is Ward Plummer, Boyd Professor of Physics. Plummer is special assistant to LSU’s vice president for research and economic development. He is a world‐renowned physicist, specializing in surfaces and interfaces phenomena
Physics undergraduate Khang Pham, a native of Vietnam, and a McNair Research Scholar, has been named a 2018 LSU Discover Scholar awardee. Currently mentored by Professor Catherine Deibel, Pham is doing research in the nuclear physics group.
The CALorimetric Electron Telescope (CALET), launched for installation on the International Space Station (ISS) in August, 2015, has been accumulating scientific data since October, 2015. CALET is intended to perform long-duration observations of high-energy cosmic rays onboard the ISS. CALET directly measures the cosmic-ray electron spectrum in the energy range of 1 GeV to 20 TeV with a 2% energy resolution above 30 GeV. In addition, the instrument can measure the spectrum of gamma rays well into the TeV range, and the spectra of protons and nuclei up to a PeV.
The International Conference on Quantum Communication, Measurement and Computing (QCMC), established in 1990 to encourage and bring together scientists and engineers working in the interdisciplinary field of quantum information science and technology, will take place March 12-16, 2018 at Louisiana State University. Organized by the LSU Quantum Science and Technologies Group (QST), the 2018 QCMC conference will highlight research areas on nano photonic quantum information and processing.
The Southeastern Universities Research Association, or SURA, announced that Gabriela González, professor of physics and astronomy at LSU and former spokesperson of the LIGO Scientific Collaboration, will receive the 2018 SURA Distinguished Scientist Award. The annual honor goes to a research scientist whose extraordinary work fulfills the SURA mission to “advance collaborative research and education” in the Southeast and nation.
LSU Professor Josef Hormes will conduct this cutting-edge research on samples of prehistoric artifacts from Poverty Point at the LSU J. Bennett Johnston, Sr., Center for Advanced Microstructures and Devices, or CAMD, with support from the National Park Service.
The LSU Chapter of the Society of Physics Students (SPS) received the 2016-2017 Distinguished Chapter Award from the national office of the SPS within the American Institute of Physics. SPS is an organization for students interested in the fields of physics and astronomy. Their primary purpose is to promote the appreciation and advancement of physics and astronomy in the community, as well as to further educate members in these fields. The LSU SPS group participates in multiple outreach events throughout the year, including Mini Maker Faire, NanoDays, International Astronomy Day, Earth Day, LASM Engineering Day, in addition to visits to middle and high schools for science fairs and similar events.
Mengxi Wu, Yongsing You, Shambhu Ghimire, David A. Reis, Dana A. Browne, Kenneth J. Schafer, and Mette B. Gaarde Phys. Rev. A 96, 063412 – Published 18 December 2017
Author: Seth Camp, Samuel Beaulieu, Kenneth J Schafer and Mette B Gaarde Published 21 February 2018 • © 2018 IOP Publishing Ltd Journal of Physics B: Atomic, Molecular and Optical Physics, Volume 51, Number 6
Siddhartha Das, George Siopsis, and Christian Weedbrook Phys. Rev. A 97, 022315 – Published 12 February 2018
If anyone is a life-long learner, it's LSU Physics alumna Leslie Austin. Leslie is from Baton Rouge and always wanted to be a Tiger. After earning her B.S. in Physics in 2000, she worked for a year as a research associate for the Department of Physics & Astronomy, traveling to Antarctica as part of the Advanced Thin Ionization Calorimeter (ATIC) project. She later went to law school at the LSU Paul M. Hebert Law Center, and then began a career in human resources (HR) with a focus on labor and employment law compliance. "I thought about obtaining an MBA, but chose law school because I was always interested in the legal system, I minored in English, and I thought patent law might be a good fit with science backgrounds." Today, she is Chief Operating Officer for HR Solutions.
For the ninth consecutive year, LSU will host NanoDays at the Highland Road Park Observatory, or HRPO, on Saturday, Feb. 24, from 2-6 p.m. followed by a presentation by David Young, a professor in the LSU Department of Physics & Astronomy, “Alternative Energy! Using nanotechnology to improve the performance of thermoelectric materials,” at 6:15 p.m.
Margarite, a native of the Baton Rouge area, is passionate about physics research. She participated in the National Institute of Standards and Technology (NIST) Summer Undergraduate Research Fellowship (SURF) program and recently presented some of her research "Multiparameter Estimation with Single Photons" at the Japan Society of Applied Physics-Optical Society of America joint symposia in Fukuoka, Japan thanks in part to the LSU Discover Travel Stipend!
China’s President Jinping Xi presented the 2017 International Science and Technology Cooperation Award of the People’s Republic of China to Professor Earl Ward Plummer, a faculty member in the LSU Department of Physics & Astronomy. Plummer was one of seven people to receive this award for his contribution to the development of science and technology in China.
A revolutionary material harbors magnetism and massless electrons that travel near the speed of light—for future ultrasensitive, high-efficiency electronics and sensors.
The Planet Hunters citizen science project announced the serendipitous discovery of KIC 8462852, a peculiar variable star observed by the NASA Kepler mission (Borucki et al. 2010) from 2009 to 2013 (Boyajian et al. 2016). KIC 8462852’s variability manifests itself as asymmetric drops in brightness of up to 22%, many of which last several days (the “dips”). There is little or no sign of periodicity in the four years of Kepler observations (but see Kiefer et al. 2017). Additionally, the duty cycle of the dips is low, occurring for less than 5% of the four-year period Kepler observed it. Subsequent ground-based follow-up observations to better characterize the star revealed nothing other than KIC 8462852 being an ordinary, main-sequence F3 star: no peculiar spectral lines, Doppler shifts indicative of orbiting companions, or signs of youth such as an infrared excess (Lisse et al. 2015; Marengo et al. 2015; Boyajian et al. 2016; Thompson et al. 2016).
We report ground-based spectrophotometry of KIC 8462852, during its first dimming events since the end of the Kepler mission. The dimmings show a clear colour-signature, and are deeper in visual blue wavelengths than in red ones. The flux loss' wavelength dependency can be described with an \AA ngstr\"om absorption coefficient of 2.19±0.45, which is compatible with absorption by optically thin dust with particle sizes on the order of 0.0015 to 0.15 μm. These particles would be smaller than is required to be resistant against blow-out by radiation pressure when close to the star. During occultation events, these particles must be replenished on time-scales of days. If dust is indeed the source of KIC 8462852's dimming events, deeper dimming events should show more neutral colours, as is expected from optically thick absorbers.
A team of more than 100 researchers, led by LSU Department of Physics & Astronomy Assistant Professor Tabetha Boyajian, is one step closer to solving the mystery behind the “most mysterious star in the universe.” KIC 8462852, or “Tabby’s Star,” nicknamed after Boyajian, is otherwise an average star. It is about 50 percent bigger and 1,000 degrees hotter than the Sun. It is more than 1,000 light years away. However, it has been inexplicably dimming and brightening sporadically like no other. Several theories abound to explain the star’s unusual light patterns including an alien megastructure orbiting the star.
Robert F. O'Connell, PhD, LSU Boyd professor, has retired after a distinguished career as a researcher, administrator and mentor. He joined the faculty of the LSU Department of Physics & Astronomy in January 1964 as a tenure-track assistant professor.
A long term program of photoelectric UBVRI photometry has been combined with AAVSO archival data for the hot, R CrB-type hydrogen deficient star MV Sgr. A deep minimum and a trend of decreasing brightness over time at maximum light thereby become evident. Variations seen via monitoring with a CCD detector also are described.
Colleen Fava, program manager of the Louisiana Space Grant Consortium (LaSPACE) / NASA EPSCoR, has been announced as one of the recipients of the 2017 LSU Foundation Staff Outstanding Service Awards. This annual award was established to recognize the superior work performance and outstanding contributions of full-time, non-academic staff employees of the LSU A&M campus and the LSU AgCenter.
This research showed the dramatic dependence of the magnetic state on the size of the crystal lattice and points out the opportunity for exploring the origins of anti-symmetric interactions through a combination of experiment, neutron scattering, and electronic structure calculation.
On Friday December 8, 2017, LSU Board of Supervisors awarded Professor Ward Plummer the rank of Boyd Professor. The Boyd Professorship is the highest professorial rank awarded by the LSU System and is given only to professors who have attained national or international distinction for outstanding teaching and research. Plummer is the 75th Boyd Professor named across LSU, and the 49th from the Flagship campus to be awarded the coveted title since it was established in 1953 to honor brothers David and Thomas Boyd, early faculty members and presidents of LSU. With this appointment, there are now 11 active Boyd Professors at the Flagship University.
On Friday, December 15, LSU Physics & Astronomy welcomed 3 new PhD, 3 MS and 2 BS graduates who conferred their degrees at the Maddox Fieldhouse.
We show that rapid optical flux variations from an accreting Galactic black-hole binary are delayed with respect to X-rays radiated from close to the black hole by about 0.1 seconds, and that this delayed signal appears together with a brightening radio jet. The origin of these subsecond optical variations has hitherto been controversial.
Physics World has announced that the Physics World 2017 Breakthrough of the Year goes to “the international team of astronomers and astrophysicists that ushered in a new era of astronomy by making the first ever multi-messenger observation involving gravitational waves.” The staff of the LIGO Livingston Observatory, together with students and scholars in residence, and including many from LSU, have worked hard for many years to operate and improve the detector, making it capable of participating in this discovery. Another LSU research project was recognized as Physics World announced its top 10 breakthroughs of the year: Ultra-high-energy cosmic rays have extra-galactic origins. LSU Department of Physics & Astronomy Professor Jim Matthews, former co-spokesperson of the Auger Collaboration, works with more than 500 scientists from 17 countries on the world’s leading science project for the exploration of the highest energy cosmic rays to elucidate the origins and properties of the most energetic particles in the universe.
Episode 3 of @LSUExperimental is out featuring @lsuscience
Former LSU PhD student Kaushik Seshadreesan and Assistant Professor Mark M. Wilde, along with their colleague Masahiro Takeoka of NICT Japan, have published their results on quantum key distribution (QKD) in Physical Review Letters. In their paper, they have calculated the maximum transmission rates for any QKD protocol conducted in a broadcast scenario over lossy channels, in which there is a single sender communicating to multiple receivers. They have found a protocol that significantly outperforms a naive time-sharing strategy, which has previously been used in QKD experiments. They have also found a different protocol that comes close to the ultimate limit for this task, and which could be implemented in practical experimental setups.
Assistant Professor Mark M. Wilde, along with colleagues Marco Tomamichel (Univ. Tech. Sydney), Mario Berta (Imperial College), and Seth Lloyd (MIT), have published their findings on quantum illumination in Physical Review Letters. In their work, they derived a formula for the relative entropy variance of quantum Gaussian states. This formula is helpful in characterizing the quantum limits on the distinguishability of quantum Gaussian states, which are states that quantum optics experimentalists can easily create and manipulate in the laboratory. They also applied the formula to quantum illumination, which is the task of determining whether there is a low-reflectivity object embedded in a target region with a bright thermal-noise bath. Wilde and his colleagues found that a quantum illumination transmitter can achieve an error probability exponent stronger than a coherent-state transmitter of the same mean photon number, and furthermore, that it requires far fewer trials to do so. This occurs when the background thermal noise is either low or bright, which means that a quantum advantage over a classical strategy is even easier to witness than in previously considered setups because it occurs for a larger range of parameters. Going forward from here, Wilde et al. expect the formula to have applications in settings well beyond those considered in their paper, especially to quantum communication tasks involving quantum Gaussian channels.
Katherine Nugent, an undergraduate student with an intriguing path into LSU's Physics & Astronomy program. This summer, Katherine helped develop comparison stars for Tabby's Star, a strange star named after LSU researcher Tabby Boyajian that displays odd dips in brightness that may be caused by dust formations. Boyajian's group may learn more about this mysterious star by comparing it's random light dips to other stars nearby.
News article " First cosmic-ray results from CALET on the ISS" about CALET in December issue of CERN Courier, p.9
Jorge Pullin has been appointed to the Advisory Board of the Journal of Universe
The hydrogen atom is the simplest system of atomic and molecular physics, while a two-qubit system is the simplest of quantum information. Remarkably, they share common symmetry aspects which are described in this paper.
Arlo U. Landolt has been elected to a term on the Council of the American Association of Variable Star Observers (AAVSO), 2017-2019.
The CALET Cosmic Ray experiment, led by Professor Shoji Torii from Waseda University in Japan, along with collaborators from LSU and other researchers in the U.S. and abroad, have successfully carried out the high-precision measurement of cosmic-ray electron spectrum up to 3 tera electron volts (TeV) by using the CALorimetric Electron Telescope (CALET) on the Japanese Experimental Module, the Exposed Facility on the International Space Station (ISS). This experiment is the first to make direct measurements of such high energy electrons in space.
More than 100 years after Albert Einstein predicted gravitational waves -- ripples in space-time caused by violent cosmic collisions -- LIGO scientists confirmed their existence using large, extremely precise detectors in Louisiana and Washington. Astrophysicist Gabriela González of the LIGO Scientific Collaboration tells us how this incredible, Nobel-winning discovery happened -- and what it might mean for our understanding of the universe. (In Spanish with English subtitles.)
Plasmons, the collective excitations of electrons in the bulk or at the surface, play an important role in the properties of materials, and have generated the field of “plasmonics.” We report the observation of a highly unusual acoustic plasmon mode on the surface of a three-dimensional topological insulator (TI) Bi2Se3, using momentum resolved inelastic electron scattering. In sharp contrast to ordinary plasmon modes, this mode exhibits almost linear dispersion into the second Brillouin zone and remains prominent with remarkably weak damping not seen in any other systems. This behavior must be associated with the inherent robustness of the electrons in the TI surface state, so that not only the surface Dirac states but also their collective excitations are topologically protected. On the other hand, this mode has much smaller energy dispersion than expected from a continuous media excitation picture, which can be attributed to the strong coupling with surface phonons.
We have studied La2/3Sr1/3MnO3 thin films grown on (3×1)-reconstructed SrTiO3 (110) substrates. Films with thicknesses less than the critical thickness of θc≅8 unit cells are insulating in the measured temperature (T) range (2–400 K). However, films with thicknesses slightly over θc exhibit reentrant nonmetallic behavior at low temperatures in addition to the normally observed metal-insulator transition at higher temperatures. In contrast, the magnetization does not show signs of low-T transitions. Such reentrance of a low-T nonmetallic phase is affected by the film thickness as well as the density of oxygen vacancies. The electrical resistivity analysis reveals that localization effects are responsible for the reentrant nonmetallic behavior, which is enhanced with reduced film thickness. Reentrance of low-temperature nonmetallic phase of L a 2 / 3 S r 1 / 3 Mn O 3 (110) thin films. Available from: https://www.researchgate.net/publication/319241498_Reentrance_of_low-temperature_nonmetallic_phase_of_L_a_2_3_S_r_1_3_Mn_O_3_110_thin_films [accessed Oct 20 2017].
Discovery made at LIGO Livingston by LSU physicists marks first cosmic event observed in both gravitational waves and light - For the first time, scientists have directly detected gravitational waves — ripples in space and time — in addition to light from the spectacular collision of two neutron stars. This marks the first time that a cosmic event has been viewed in both gravitational waves and light. The discovery was made using the U.S.-based Laser Interferometer Gravitational-Wave Observatory, or LIGO; the Europe-based Virgo detector; and some 70 ground- and space-based observatories.