Category Physics

Network of conducting and insulating rivers as seen in a metal-oxide in the middle of a phase transition. Credit: A.S. Mueller

Physicists have for the first time succeeded in directly visualising on small scales how a material abruptly changes its state from conducting to insulating at low temperatures. Researchers provide evidence for a 60-year-old theory that explains this phenomenon and pave the way for more energy efficient technologies. Materials that conduct electricity at high temperature but are insulating at lower temperatures have been known for decades. However, until recently it was not possible to directly measure how such phase transitions proceed on small length scales...

Spatiotemporal optical vortices, or STOVs (thin, gray ringlike objects), are newly described three-dimensional light structures that strongly resemble smoke rings. Unlike other laser vortices, STOVs are time dynamic, which means that they travel along with the central laser pulse. Compared to other laser vortices, STOVs could prove more broadly useful for engineering applications. Credit: Howard Milchberg

3-D ring structures made by high-intensity lasers could aid the design of powerful microscopes and more efficient telecommunication lines...

To direct-write the logo of the Department of Energy’s Oak Ridge National Laboratory, scientists started with a gray-scale image. They used the electron beam of an aberration-corrected scanning transmission electron microscope to induce palladium from a solution to deposit as nanocrystals. Image credit: Oak Ridge National Laboratory, U.S. Dept. of Energy

A scanning transmission electron microscope (STEM) has been harnessed for the first time to directly write tiny patterns in metallic “ink,” forming features in liquid that are finer than half the width of a human hair. The automated process is controlled by weaving a STEM instrument’s electron beam through a liquid-filled cell to spur deposition of metal onto a silicon microchip...

Credit: CC0 Public Domain

Are time crystals just a mathematical curiosity, or could they actually physically exist? Physicists have been debating this question since 2012, when Nobel laureate Frank Wilczek first proposed the idea of time crystals. He argued that these hypothetical objects can exhibit periodic motion, such as moving in a circular orbit, in their state of lowest energy, or their “ground state.” Theoretically, objects in their ground states don’t have enough energy to move at all. Even though time crystals couldn’t be used to generate useful energy (since disturbing them makes them stop moving), and don’t violate the second law of thermodynamics, they do violate a fundamental symmetry of the laws of physics.

However, now UCSB physicists and Microsoft Station Q, UCSB campus ha...