Physics & Astronomy News

Student Spotlight: Margarite LaBorde, a double major in Physics and Math

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 Presents Top Foreign Science and Technology Award to LSU Professor

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 Rare Quantum State Realized in a New Material

A revolutionary material harbors magnetism and massless electrons that travel near the speed of light—for future ultrasensitive, high-efficiency electronics and sensors.

The First Post-Kepler Brightness Dips of KIC 846285

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).

Non-grey dimming events of KIC 8462852 from GTC spectrophotometry

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.

New Data Debunks Alien Megastructure Theory on the ‘Most Mysterious Star in the Universe’

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.

LSU Boyd Professor O'Connell Retires After 53-Year Career

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.

"Multi-color Photometry of the Hot R Coronae Borealis Star, MV Sagittarii," by Arlo U. Landolt and James L. Clem, 2017, Journal of the American Association of Variable Stars (JAAVSO), volume 45, page 159.

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 Honored with Outstanding Service Award

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.

The DOE Office of Science recently published a scientific research highlight: Chemical “Pressure” Tuning Magnetic Properties

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.

Ward Plummer Named Boyd Professor, the Highest and Most Prestigious Academic Rank at LSU

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.

Fall 2017 Graduates

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.

"An elevation of 0.1 light-seconds for the optical jet base in an accreting Galactic black hole system" by P. Gandhi, R. Hynes, et al. Nature Astronomy 1, 859–864 (2017)

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.

LSU Research Contributes to Two Physics World 2017 Breakthroughs of the Year

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.

PhD graduate student Jonathan Cripe telling us about the next generation black hole detectors he builds and the exciting discoveries with LIGO collaborators

Episode 3 of @LSUExperimental is out featuring @lsuscience

"Unconstrained Capacities of Quantum Key Distribution and Entanglement Distillation for Pure-Loss Bosonic Broadcast Channels" by Takeoka, Seshadreesan, and Wilde. Phys. Rev. Lett. 119, 150501

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.

"Gaussian Hypothesis Testing and Quantum Illumination" by Mark M. Wilde, et al. Phys. Rev. Lett. 119, 120501

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.

Katie Nugent: My Star-Studded LSU Astronomy Experience

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.

"First cosmic-ray results from CALET on the ISS" in December issue of CERN Courier, p.9

News article " First cosmic-ray results from CALET on the ISS" about CALET in December issue of CERN Courier, p.9