Research Highlights

A new study led by Stony Brook University researchers Tzu-Chieh Wei and Hongye Yu and published in Nature Communications, “Universal energy-space localization and stable quantum phases against time-dependent perturbations,” offers a striking new perspective on the stability of quantum systems. The researchers demonstrate a universal phenomenon known as energy-space localization, showing that certain quantum systems can remain remarkably close to their original state even when subjected to disturbances that change continuously over time.

The work addresses a longstanding challenge in quantum physics: while stability against fixed, static perturbations is relatively well understood, determining whether quantum systems can withstand general time-dependent disturbances has proven considerably more difficult. The researchers’ results establish that, for systems with sufficiently large energy barriers, quantum states can remain localized for exponentially long periods despite these changing perturbations.

The findings have important implications for both quantum information and computation. In particular, the study demonstrates how this stability can help protect quantum information encoded in certain low-density parity-check (LDPC) error-correcting codes, potentially providing valuable insight into how quantum systems can withstand realistic, time-varying noise.

At the same time, the remarkable stability revealed by the work presents an intriguing paradox: what protects quantum information can also hinder quantum optimization. In some computational problems, large energy barriers can trap a quantum system near a suboptimal solution, preventing it from reaching better ones.

By connecting quantum dynamics, error correction, and computational complexity, this elegant theoretical work provides a powerful new framework for understanding—and ultimately harnessing—the extraordinary stability of quantum systems.

The LHC is the world’s most powerful particle collider, located at CERN, the European Organization for Nuclear Research, and the measurements reveal how the distribution of particles is driven by pressure gradients generated by the extreme conditions in these collisions, which mimic what the universe was like just after the Big Bang.

The research is described in a paper published in Physical Review Letters by the ATLAS Collaboration at the LHC.

The international team used data from the LHC’s ATLAS experiment to analyze how particles flow outward in radial directions when two beams of lead ions — lead atoms stripped of their electrons — collide after circulating around the 17-mile circumference of the LHC at close to the speed of light.

“Earlier measurements revealing that particles flow collectively from heavy ion collisions were central to the discovery of the quark-gluon plasma at the Relativistic Heavy Ion Collider (RHIC),” said Jiangyong Jia, a physicist and professor at Stony Brook University and Brookhaven Lab, where RHIC operates as a DOE Office of Science user facility for nuclear physics research. Jia conducts research at both the RHIC and the LHC and led the new ATLAS analysis.

“The new results from ATLAS, while confirming the fluid-like nature of the QGP (quark-gluon plasma), also reveal something new because the type of flow we studied, ‘radial’ flow, has a different geometric origin from the ‘elliptic’ flow studied previously, and it is sensitive to a different type of viscosity in the fluid system,” Jia said.

The findings offer new insight into the nature of the hot, dense matter generated in these collisions, with temperatures more than 250,000 times hotter than the Sun’s core. These extreme conditions essentially melt the protons and neutrons that make up the colliding ions, setting free their innermost building blocks, quarks and gluons, to create a quark-gluon plasma.

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.