From bits to atoms.
Category: particle physics – Page 24
Criticality in Nature’s Strongest Force
Experiments at the Relativistic Heavy Ion Collider give the first hints of a critical point in the hot quark–gluon “soup” that is thought to have pervaded the infant Universe.
The strongest force of nature—the one holding nuclear matter together—is described by the theory of quantum chromodynamics (QCD). The fundamental particles of QCD are quarks and gluons, which are normally bound within composite particles called hadrons—the most well-known of which are protons and neutrons. Only at extreme temperatures around 1012 K (a million times hotter than the core of the Sun) can quarks and gluons become deconfined, leading to a new phase of matter called the quark–gluon plasma. At vanishing densities, the transition between confined hadrons and the quark–gluon plasma is known to be ill-defined—happening across a wide range of temperatures rather than at a specific temperature. But theory predicts that at large densities and moderately high temperatures, a critical point exists, where the “fuzziness” disappears and a clear distinction can be made between the gas-like hadrons and the liquid-like quark–gluon mix [1–3].
World’s most sensitive detector tightens the net on elusive dark matter
Determining the nature of dark matter, the invisible substance that makes up most of the mass in our universe, is one of the greatest puzzles in physics. New results from the world’s most sensitive dark matter detector, LUX-ZEPLIN (LZ), have narrowed down the possibilities for one of the leading dark matter candidates: weakly interacting massive particles (WIMPs).
High-order analysis reveals more signs of phase-change ‘turbulence’ in nuclear matter
Members of the STAR collaboration, a group of physicists collecting and analyzing data from particle collisions at the Relativistic Heavy Ion Collider (RHIC), have published a new high-precision analysis of data on the number of protons produced in gold-ion smashups over a range of energies.
The results, published in Physical Review Letters, suggest scientists have observed one part of a key signature of a “critical point.” That’s a unique point on the “map” of nuclear phases that marks a change in the way quarks and gluons, the building blocks of protons and neutrons, transition from one phase of matter to another.
Discovering the critical point has been a central goal of research at RHIC, a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory. Like centuries-old efforts to map out the solid, liquid, and gaseous phases of substances like water, it’s considered essential for fully understanding and describing the quark-gluon plasma.
In a first, scientists observe short-range order in semiconductors
Inside the microchips powering your devices, atoms aren’t just randomly scattered. They follow a hidden order that can change how semiconductors behave.
A team of researchers from the Lawrence Berkeley National Laboratory (Berkeley Lab) and George Washington University has, for the first time, observed these tiny patterns, called short-range order (SRO), directly in semiconductors.
This discovery is a game-changer, as understanding how atoms naturally arrange themselves could let researchers design materials with desirable electronic properties. Such control could revolutionize quantum computing, neuromorphic devices that mimic the brain, and advanced optical detectors.
The surprising new particle that could finally explain dark matter
Physicists are eyeing charged gravitinos—ultra-heavy, stable particles from supergravity theory—as possible Dark Matter candidates. Unlike axions or WIMPs, these particles carry electric charge but remain undetectable due to their scarcity. With detectors like JUNO and DUNE, researchers now have a chance to spot their unique signal, a breakthrough that could link particle physics with gravity.
Controlling Light Emission with Photonic Time Crystals
A material whose dielectric properties vary in time could produce exotic light-emission phenomena in a nearby atom, theorists predict.
Traditional photonic technologies rely on mirrors, lenses, and diffraction gratings to shape light as it travels through a medium. Recent advances in material science have opened a strikingly different route. Instead of sculpting material properties in space, researchers can now dynamically modulate them in time [1]. Such temporal modulation transforms a passive medium into an active one, as the act of modulation itself can inject or extract energy. Adding a temporal dimension to material design confronts long-standing notions of light–matter interactions and reveals phenomena with no static counterpart. Now Bumki Min of the Korea Advanced Institute of Science and Technology (KAIST) and his collaborators have exploited this capability to reshape the photonic density of states (DOS), which quantifies the number of available optical modes into which light can be emitted [2].