Research Highlights
Stony Brook Researchers Redefine Capacitor Behavior at the Nanoscale
Stony Brook University researchers led a new study published in Physical Review Letters that overturns long-standing assumptions about how capacitors operate when engineered at the nanoscale, offering a clearer scientific foundation for future nanoscale electronic devices.
Capacitors—core components of modern electronics—store electrical charge between metallic electrodes separated by a dielectric material. While their performance is well understood at macroscopic scales, conventional models break down at the nanoscale, where the material properties assumed in standard equations are no longer well defined. These discrepancies pose significant challenges for interpreting the dielectric response of ultrathin materials and for designing reliable nanocapacitors.
To address this problem, the SBU team developed a quantum-mechanical framework that unambiguously separates the contributions of the electrodes and the dielectric. The new protocol establishes fundamental limits on how small a capacitor can be made and provides a reliable approach for evaluating the intrinsic behavior of nanoscale insulating materials.
Demonstrating the method on ultrathin ice, the researchers found that its electronic response to electric fields is essentially indistinguishable from that of bulk ice, despite extreme confinement. The result resolves discrepancies between theoretical predictions and experimental measurements of ice films only a few molecules thick.
“This work offers a pathway to accurately characterize ultrathin dielectric materials using first-principles calculations,” said Ph.D. candidate Anthony Mannino, the study’s lead author. “With a clearer understanding of nanoscale dielectric behavior, we can improve device design and better interpret experimental data.”
The study was led by Mannino, together with fellow Ph.D. candidate Kedarsh Kaushik and visiting student Graciele M. Arvelos, under the direction of Professor Marivi Fernández-Serra at Stony Brook University’s Institute for Advanced Computational Science (IACS), where Mannino is a recipient of the IACS Graduate Fellowship.
Astronomers Sharpen the Universe’s Expansion Rate, Deepening a Cosmic Mystery
A team of astronomers using a variety of ground and space-based telescopes including the W. M. Keck Observatory on Maunakea, Hawaiʻi Island, have made one of the most precise independent measurements yet of how fast the universe is expanding, further deepening the divide on one of the biggest mysteries in modern cosmology.
Using data gathered from Keck Observatory’s Cosmic Web Imager (KCWI) as well as NASA’s James Webb Space Telescope (JWST), the Hubble Space Telescope (HST) the Very Large Telescope (VLT), and European Organisation for Astronomical Research in the Southern Hemisphere (ESO) researchers have independently confirmed that the universe’s current rate of expansion, known as the Hubble constant (H₀), does not match values predicted from measurements from the universe when it was much younger.
The finding strengthens what scientists call the “Hubble tension,” a cosmic disagreement that may point to new physics governing the universe.
“What many scientists are hoping is that this may be the beginning of a new cosmological model,” said Tommaso Treu, Distinguished Professor of Physics and Astronomy at the University of California Los Angeles and one of the authors of the study published in Astronomy and Astrophysics.
“This is the dream of every physicist. Find something wrong in our understanding so we can discover something new and profound,” added Simon Birrer, Assistant Professor of Physics at the Stony Brook University and one of the corresponding authors of the study.
The team’s measurement currently achieves 4.5% precision — an extraordinary feat, but not yet enough to confirm the discrepancy beyond doubt. The next goal is to refine that precision to better than 1.5%, a level of certainty “probably more precise than most people know how tall they are,” noted Martin Millon, postdoctoral fellow at ETH Zurich and the third corresponding author of the study.
James Webb Space Telescope Looks Within for Dark Matter
Since its launch in 2021, the JWST has observed not just galaxies at the edge of the visible Universe but also our nearest stellar neighbor, Proxima Centauri. Now Peizhi Du at the University of Science and Technology of China, formerly a postdoctoral researcher at Stony Brook, as well as Stony Brook Professor Rouven Essig and his recent graduate student Hailin Xu, and NASA scientist Bernie Rauscher, have used the JWST to look for objects that are even closer. By analyzing ostensibly blank calibration images, the team sought signs of dark matter within the telescope itself. Finding none, the researchers put constraints on the existence of dark matter that interacts strongly with ordinary matter.
The team considered one proposed type of dark matter that interacts with electrically charged particles. The strength of this interaction is orders of magnitude feebler than that of electromagnetism but is still sufficiently large that it would hinder the particles’ passage through Earth’s atmosphere. Such dark matter is therefore expected to be especially hard to spot using typical ground-based experiments. Instead, space-based instruments offer a promising alternative.
The team analyzed images acquired when JWST’s near-infrared spectrograph was covered. These images were obtained so that researchers could characterize the instrument’s noise. Even so, although the sensor was protected from external photons, pixels could still record cosmic rays and internally generated radiation. Du and colleagues filtered out those events in the hope of finding a residual signal caused by strongly interacting dark matter. The absence of such a signal implies that this form of dark matter contributes no more than 0.4% to the Universe’s total.
This work was published in PRL, selected as an Editor's Suggestion and featured in Physics.
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Late Prof. C.N. "Frank" Yang: 1922 - 2025