News and Events

Thumbnail of NGC 6960: The Witch's Broom Nebula
Ten thousand years ago, before the dawn of recorded human history, a new light would suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant. This sharp telescopic view is centered on a western segment of the Veil Nebula cataloged as NGC 6960 but less formally known as the Witch's Broom Nebula. Blasted out in the cataclysmic explosion, an interstellar shock wave plows through space sweeping up and exciting interstellar material. Imaged with narrow band filters, the glowing filaments are like long ripples in a sheet seen almost edge on, remarkably well separated into atomic hydrogen (red) and oxygen (blue-green) gas. The complete supernova remnant lies about 1400 light-years away towards the constellation Cygnus. This Witch's Broom actually spans about 35 light-years. The bright star in the frame is 52 Cygni, visible with the unaided eye from a dark location but unrelated to the ancient supernova remnant.
Mount Timpanogos with sky above
Temp:  59 °FN2 Boiling:75.9 K
Humidity: 31%H2O Boiling:   368.5 K
Pressure:86 kPaSunrise:7:10 AM
Wind:2 m/s   Sunset:5:12 PM
Precip:0 mm   Sunlight:0 W/m²  
Image for Drs. Davis and Vanfleet Receive Technology Transfer Award
BYU Physics and Astronomy Professors Dr. Davis and Dr. Vanfleet recently received the 2024 award for outstanding achievement in technology transfer from the BYU Technology Transfer Office.
Image for New Acoustics Major
The BYU Physics & Astronomy department recently introduced the Applied Physics: Acoustics degree.
Image for Chris Verhaaren Creates Particle Physics Class
After 3 years of being offered as 513R, elementary particle physics is finally an official course and accepted for credit in the physics major!
Image for A Practical Scientist’s Field Guide to Dealing with Science and Religion.
Dr. Michael Ware hopes to help students develop the skills to navigate discussion of science and religion

Selected Publications

Thumbnail of figure from publication
Karen A. Della Corte, Tyler Bosler, Cole McClure, James D. LeCheminant, and Dennis Della Corte (et al.)

Objective

To investigate the dose-response relationship between dietary sugar and T2D risk.

Methods

MEDLINE, Embase, CINAHL, Web of Science and Cochrane databases were searched through July 9, 2024 for prospective cohorts reporting relative measures of incident T2D risk by categories of dietary sugar (total, free, added, fructose, sucrose) or two beverage sources (non-diet SSB, fruit juice) in healthy adults (Prospero ID: CRD42023401800). Linear and restricted cubic spline dose-response models were fitted for each exposure and study-specific slopes and confidence intervals (CIs) were calculated. Heterogeneity was evaluated using Q-statistics. Risk of bias was evaluated using ROBINS-E tool GRADE approach was applied to assess the certainty of evidence.

Results

Of 10,384 studies, 29 cohorts were included: SSB:18 (n = 541,288); fruit juice:14 (n = 490,413); sucrose: 7 (n = 223,238); total sugar: 4 (n = 109,858); fructose: 5 (n = 158,136); and added sugar: 2 (n = 31,004). Studies were conducted in Europe (13), USA (11), Asia (6), Australia (4), and Latin America (3). Each additional serving of SSB and fruit juice was associated with a higher risk of T2D (RR: 1.25; 95% CI: 1.17–1.35 and RR: 1.05; 95% CI: >1.00–1.11, respectively; moderate certainty). In contrast, 20 g/d intakes of total sugar and sucrose were inversely associated with T2D (RR: 0.96; 95% CI: 0.94–0.98; low certainty; and RR: 0.95; 95% CI: 0.91– <1.00; moderate certainty, respectively). No associations for added sugar (RR: 0.99; 95% CI: 0.96–1.01; low certainty) or fructose (RR: 0.98; 95% CI: 0.83–1.15; very low certainty).

Conclusion

These findings suggest that dietary sugar consumed as a beverage (SSB and fruit juice) is associated with incident T2D risk. The results do not support the common assumption that dietary sugar (i.e., total sugar and sucrose), irrespective of type and amount, is consistently associated with increased T2D risk.

Thumbnail of figure from publication
Daniel Hodge and Richard Sandberg (et al.)

The last decade has shown the great potential that X-ray Free Electron Lasers (FEL) have to study High Energy Density (HED) physics. Experiments at FELs have made significant breakthroughs in Shock Physics and Dynamic Diffraction, Dense Plasma Physics and Warm Dense Matter Science, using techniques such as isochoric heating, inelastic scattering, small angle scattering and X-ray diffraction. In addition, and complementary to these techniques, the coherent properties of the FEL beam can be used to image HED samples with high fidelity. We present new imaging diagnostics and techniques developed at the Matter in Extreme Conditions (MEC) instrument at Linac Coherent Light Source (LCLS) over the last few years. We show results in Phase Contrast Imaging geometry, where the X-ray beam propagates from the target to a camera revealing its phase, as well as in Direct Imaging geometry, where a real image of the sample plane is produced in the camera with a spatial resolution down to 200 nm. Last, we show an implementation of the Talbot Imaging method allowing both X-ray phase and intensity measurements change introduced by a target with sub-micron resolution.

Thumbnail of figure from publication
Trigg Randall, Levi Homer, Garrett Davis, and John S. Colton (et al.)

Hybrid perovskite dimensional engineering enables the creation of one- to three-dimensional (1D to 3D) networks of corner-sharing metal halide octahedra interspersed by organic cations, offering opportunities to tailor semiconducting properties through quantum- and dielectric-confinement effects. Beyond the discrete options, intermediate dimensionality has been introduced in the form of quasi-2D phases with inorganic layers of varying thickness. The current study extends this approach to quasi-1D lead-iodide systems with variable ribbon widths from 2 to 6 octahedra, stabilized by flexible molecular configurations, cation mixing of organic cations, or guest molecule selection. This family of quasi-1D structures adopts characteristic well-like configurations, with intraoctahedral distortion increasing from the core to the edges. First-principles density-functional theory (DFT) calculations and optical characterizations─i.e., temperature-dependent UV–visible absorption, electro-absorption, photoluminescence, and circular dichroism─collectively demonstrate lower bandgap and exciton binding energy with increased ribbon width due to tailorable quantum confinement and structural distortions. Access to two ribbon widths within a single well-ordered structure yields distinguishable bandgaps and excitonic properties, demonstrating a class of dual-quantum confinement materials within the perovskite family. Our study serves as a starting point, showcasing a paradigm to stabilize increased ribbon widths through further tuning of organic templating effects. This continuum between 2D and 1D structures offers promise for fine-tuning the dimensionality and optoelectronic properties of hybrid perovskites.

Thumbnail of figure from publication
Michael C. Mortenson, Tracianne B. Neilsen, and David F. Van Komen (et al.)

In shallow-water downward-refracting ocean environments, hydrophone measurements of shipping noise encode information about the seabed. In this study, neural networks are trained on synthetic data to predict seabed classes from multichannel hydrophone spectrograms of shipping noise. Specifically, ResNet-18 networks are trained on different combinations of synthetic inputs from one, two, four, and eight channels. The trained networks are then applied to measured ship spectrograms from the Seabed Characterization Experiment 2017 (SBCEX 2017) to obtain an effective seabed class for the area. Data preprocessing techniques and ensemble modeling are leveraged to improve performance over previous studies. The results showcase the predictive capability of the trained networks; the seabed predictions from the measured ship spectrograms tend towards two seabed classes that share similarities in the upper few meters of sediment and are consistent with geoacoustic inversion results from SBCEX 2017. This work also demonstrates how ensemble modeling yields a measure of precision and confidence in the predicted results. Furthermore, the impact of using data from multiple hydrophone channels is quantified. While the water sound speed in this experiment was only slightly upward refracting, we anticipate increased advantages of using multiple channels to train neural networks for more varied sound speed profiles.

Thumbnail of figure from publication

The coupling between structural, electronic and magnetic degrees of freedom across the metal-insulator transition in V2O3 makes it hard to determine the main driving mechanism behind the transition. Specifically, the role of magnetism is debated and its interplay with the other transitions has not been established. To address this issue, this work uses a combination of muon spin relaxation/rotation, electrical transport and reciprocal space mapping which allows to correlate magnetic, electronic and structural degrees of freedom in strain-engineered V2O3 thin films. Evidence is found for a magnetic instability in the vicinity of the structural transition. This is manifested as a decrease in the antiferromagnetic moment in proximity to the structural and electronic transitions. Moreover, this work finds evidence for an onset of antiferromagnetic (AF) fluctuations in the rhombohedral phase even without a structural transition to the monoclinic phase. In samples where the transition is most strongly suppressed by strain, a depth-dependent magnetic state is observed. These results reveal the importance of an AF instability in the paramagnetic phase in triggering the metal-insulator transition and the crucial role of the structural transition in allowing for the formation of an ordered AF state.

Thumbnail of figure from publication
Rylee S. Russell, Brian E. Anderson, and Michael H. Denison

Time Reversal (TR) is a signal processing technique that can be used to focus acoustic waves to a specific location in space, with most applications aiming to create an impulsive focus. This study instead aims to focus long-duration noise signals using TR. This paper seeks to generate higher amplitude noise at a desired location over an existing method of broadcasting equalized noise. Additionally, this paper explores various characteristics associated with focusing long duration noise using TR. The dependence of the focal amplitude on the duration of the focused signal is explored as well as the implications of using multiple sources when focusing noise. The focal amplitude decreases with longer duration and then levels off when the duration exceeds a few seconds. Coherent addition of focused noise is observed if all loudspeakers have coherent noise signals convolved with their reversed impulse responses. Lastly, focusing noise with a desired spectrum is explored.