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. Read More
Jorge Pullin has co-edited with Abhay Ashtekar, the Eberly Chair of Physics at the Pennsylvania State University, the volume "Loop quantum gravity: the first 30 years". It includes eight chapters by young emerging leaders of the field providing a snapshot of its state of the art, including one by LSU's Ivan Agullo and Parampreet Singh. The book is part of the series that World Scientific Publishing Co. of Singapore is putting out to celebrate the 100 years of Einstein's General Theory of Relativity. According to the publisher, It will include "two dozen excellent monographs written by top-notch authors from the international gravitational community".
Mark Wilde's Second Edition of his book "Quantum Information Theory" has been published.
Developing many of the major, exciting, pre- and post-millennium developments from the ground up, this book is an ideal entry point for graduate students into quantum information theory. Significant attention is given to quantum mechanics for quantum information theory, and careful studies of the important protocols of teleportation, superdense coding, and entanglement distribution are presented. In this new edition, readers can expect to find over 100 pages of new material, including detailed discussions of Bell's theorem, the CHSH game, Tsirelson's theorem, the axiomatic approach to quantum channels, the definition of the diamond norm and its interpretation, and a proof of the Choi–Kraus theorem. Discussion of the importance of the quantum dynamic capacity formula has been completely revised, and many new exercises and references have been added. This new edition will be welcomed by the upcoming generation of quantum information theorists and the already established community of classical information theorists.
LSU Physicists Collaborate on T2K CP Violation Results to Explain Workings of Universe: LSU physicists Thomas Kutter and Martin Tzanov were among the international T2K Collaboration who recently announced their findings on the symmetry between neutrino and antineutrino oscillation. With newly collected antineutrino data, T2K has performed a new analysis, fitting both neutrino and antineutrino modes simultaneously. T2K’s new data continue the trends observed in 2015, which is a preference for maximal disappearance of muon neutrinos, as well as a discrepancy between the electron neutrino and electron antineutrino appearance rates. Read more
The LIGO Scientific Collaboration and the Virgo collaboration identify a second gravitational
wave event in the data from Advanced LIGO detectors. On December 26, 2015 at 03:38:53 UTC, scientists observed gravitational waves-ripples
in the fabric of spacetime-for the second time. The gravitational waves were detected
by both of the twin Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors,
located in Livingston, Louisiana, and Hanford, Washington, USA. Read more
“CALET Upper Limits on X-Ray and Gamma-Ray Counterparts of GW 151226” has been published by the CALET collaboration including Nick Cannady, Mike Cherry Greg Guzik, Amir Javaid, John Wefel et al. in Astrophysical Journal Letters, 829:L20 (2016). The CALET experiment aboard the International Space Station has placed upper limits for counterpart emission in the 7-1000 keV and 1-100 GeV bands associated with the gravitational wave event GW 151226 corresponding to a luminosity of 3-4 ×1049 erg s−1, which is signiﬁcantly lower than typical short gamma ray bursts. Read more
Extreme light from frozen argon LSU physicists Mette Gaarde, Mengxi Wu, Kenneth Schafer, and Dana Browne, in collaboration with a team of researchers at SLAC/Stanford University have directly compared the ultrafast, extreme ultraviolet radiation emitted by argon atoms when they are in their gas phase or in their weakly bound solid phase and found significant differences between them, as reported today in the journal Nature. The results yield new clues about how energetic electrons in a solid behave, and may yield new compact sources of short wavelength radiation. Read more
"Efficacy of the SU(3) scheme for ab initio large-scale calculations beyond the lightest nuclei" has been published by Tomas Dytrych, Kristina Launey, and Jerry Draayer et. al. Comp. Phys. Commun. 207 (2016) 202; doi: 10.1016/j.cpc.2016.06.006. This paper discuss the computational characteristics of ab initio nuclear structure calculations in the symmetry-adapted no-core shell model (SA-NCSM) framework and examine the computational complexity of the current implementation of the SA-NCSM approach, dubbed LSU3shell, by analyzing ab initio results for Li-6 and C-12 in large harmonic-oscillator model spaces and symmetry-selected subspaces. We demonstrate LSU3shell's strong-scaling properties achieved with highly-parallel methods for computing the many-body matrix elements. In particular, a well-chosen symmetry-adapted basis affords memory savings in calculations of states with a fixed total angular momentum in large model spaces while exactly preserving translational invariance.
"Quantum self-gravitating collapsing matter in a quantum geometry". has been published by Campiglia, Gambini, Olmedo, and Pulin. Classical and Quantum Gravity, Volume 33, Number 18. The problem of how space–time responds to gravitating quantum matter in full quantum gravity has been one of the main questions that any program of quantization of gravity should address. Here we analyze this issue by considering the quantization of a collapsing null shell coupled to spherically symmetric loop quantum gravity. We show that the constraint algebra of canonical gravity is Abelian both classically and when quantized using loop quantum gravity techniques. The Hamiltonian constraint is well defined and suitable Dirac observables characterizing the problem were identified at the quantum level. We can write the metric as a parameterized Dirac observable at the quantum level and study the physics of the collapsing shell and black hole formation. We show how the singularity inside the black hole is eliminated by loop quantum gravity and how the shell can traverse it. The construction is compatible with a scenario in which the shell tunnels into a baby universe inside the black hole or one in which it could emerge through a white hole.
"Ultrathin two-dimensional superconductivity with strong spin–orbit coupling" has been published by Nam, Kim and Adams, et. al. doi:10.1073/pnas.1611967113. September, 2016. We report on a study of epitaxially grown ultrathin Pb films that are only a few atoms thick and have parallel critical magnetic fields much higher than the expected limit set by the interaction of electron spins with a magnetic field, that is, the Clogston–Chandrasekhar limit. The epitaxial thin films are classified as dirty-limit superconductors because their mean-free paths, which are limited by surface scattering, are smaller than their superconducting coherence lengths. The uniformity of superconductivity in these thin films is established by comparing scanning tunneling spectroscopy, scanning superconducting quantum interference device (SQUID) magnetometry, double-coil mutual inductance, and magneto-transport, data that provide average superfluid rigidity on length scales covering the range from microscopic to macroscopic. We argue that the survival of superconductivity at Zeeman energies much larger than the superconducting gap can be understood only as the consequence of strong spin–orbit coupling that, together with substrate-induced inversion-symmetry breaking, produces spin splitting in the normal-state energy bands that is much larger than the superconductor’s energy gap.
"Schrödinger-like quantum dynamics in loop quantized black holes" has been published by Gambini, Rodolfo, Javier Olmedo, and Jorge Pullin. • Int.J.Mod.Phys. D25 (2016) no.08, 1642006 arXiv:1605.00969. This paper show, following a previous quantization of a vacuum spherically symmetric spacetime carried out in [R. Gambini, J. Olmedo and J. Pullin, Class. Quantum Grav. 31 (2014) 095009.] that this setting admits a Schrödinger-like picture. More precisely, the technique adopted there for the definition of parametrized Dirac observables (that codify local information of the quantum theory) can be extended in order to accommodate different pictures. In this new picture, the quantum states are parametrized in terms of suitable gauge parameters and the observables constructed out of the kinematical ones on this space of parametrized states.
Rob Hynes, Brad Schaefer, undergrad Zach Baum, Ching-Cheng Hsu, Mike Cherry et al. present a multi-wavelength study of the low-mass X-ray binary Sco X-1 in "Kepler
K2 Observations of Sco X-1: Orbital Modulations and Correlations with Fermi GBM and
MAXI" in Monthly Notices of the Royal Astronomical Society. Read more
The research of LSU Physicist James Matthews and an international team of scientists is featured in the CERN Courier. The world's
largest cosmic-ray experiment, the Pierre Auger Observatory in Mendoza Province, Argentina, is embarking on its next
phase, named AugerPrime. Read more
The paper "Angular momentumprojection for a Nilsson mean-field plus pairing model", Nucl. Phys. A 950 (2016) 1; doi:10.1016/j. nuclphysa. 2016.03.012. by Yin Wang, Feng Pan, Kristina D. Launey, Yan-An Luo, and J. P. Draayer, explores the interplay of pairing and deformation in intermediate-mass nuclei based on a new method for restoring the rotational invariance of a general nuclear pairing-plus-deformation Hamiltonian. Read more
Gravitational Waves Detected 100 Years After Einstein's Prediction: For the first time, scientists have observed ripples in the fabric of spacetime, called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein's 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.