Record-breaking results provide strongest constraints yet on low-mass WIMPs, proposed dark matter particles; experiment also detected boron-8 solar neutrinos
Category: particle physics
Sharp Diffraction Pattern Produced by Atoms Passing Through Graphene
Researchers have generated high-quality atom diffraction data from graphene, which could lead to new ways to measure surface interactions.
A beam of neutral atoms striking a material can produce a diffraction pattern that is sensitive to short-range interactions between the atoms and the surface. Building on recent developments, Pierre Guichard from the University of Strasbourg in France and collaborators have now used a fast hydrogen beam to probe single-layer graphene, producing the sharpest graphene diffraction patterns to date [1].
Early atom diffraction experiments predominantly looked at reflection, because atoms transmitted through a material tend to lose their wave-like coherence. Recently, however, transmitted atoms were shown to produce a diffraction pattern from single-layer graphene [2]. The trick was to use fast atoms that traverse the target quickly, minimizing coherence-destroying interactions.
Twisted light-matter systems unlock unusual topological phenomena
Properties that remain unchanged when materials are stretched or bent, which are broadly referred to as topological properties, can contribute to the emergence of unusual physical effects in specific systems.
Over the past few years, many physicists have been investigating the physical effects emerging from the topology of non-Hermitian systems, open systems that exchange energy with their surroundings.
Researchers at Nanyang Technological University and the Australian National University set out to probe non-Hermitian topological phenomena in systems comprised of light and matter particles that strongly interact with each other.
Researchers discover a new superfluid phase in non-Hermitian quantum systems
A stable “exceptional fermionic superfluid,” a new quantum phase that intrinsically hosts singularities known as exceptional points, has been discovered by researchers at the Institute of Science Tokyo.
Their analysis of a non-Hermitian quantum model with spin depairing shows that dissipation can actively stabilize a superfluid with these singularities embedded within it. The work reveals how lattice geometry dictates the phase’s stability and provides a path to realizing it in experiments with ultracold atoms.
In the quantum world, open quantum systems are those where particle loss and directional asymmetry are fundamental features. These systems can no longer be described by conventional mathematics.
Evidence of a quantum spin liquid ground state in a kagome material
Quantum spin liquids are exotic states of matter in which spins (i.e., the intrinsic angular momentum of electrons) do not settle into an ordered pattern and continue to fluctuate, even at extremely low temperatures. This state is characterized by high entanglement, a quantum effect that causes particles to become linked so that the state of one affects the others’ states, even over long distances.
Researchers at SLAC National Accelerator Laboratory and Stanford University recently gathered evidence of intrinsic quantum spin liquid behavior in a kagome material, a magnetic material in which atoms are arranged in a particular pattern known as a kagome lattice. Their findings, published in Nature Physics, could help to further delineate the fundamental principles underpinning quantum spin liquid states.
“I’ve been interested in understanding quantum spin liquids for the past 20+ years,” Young S. Lee, senior author of the paper, told Phys.org. “These are fascinating new states of quantum matter. In principle, their ground states may possess long-range quantum entanglement, which is extremely rare in real materials.
Bose-Einstein Condensate; When Atoms Act As One
Bose–Einstein Condensate (BEC) explained: Cool a dilute gas of atoms to billionths of a degree above absolute zero and they merge into one coherent matter wave—a Bose–Einstein condensate. This video covers laser cooling, magnetic/optical traps, evaporative cooling, the onset of quantum degeneracy, and why a BEC behaves like a superfluid. See signatures: interference fringes, quantized vortices, long coherence length, and frictionless flow. Applications include atom interferometers (precision gravity and rotation sensing), quantum simulation of complex materials, and space-based experiments (ISS Cold Atom Lab). We also touch on first BECs (1995, rubidium/sodium), critical temperature, and why bosons condense while fermions do not.
Safe and affordable fast-charging batteries: Multi-layered alkali metal structures open the door to energy of the future
Skoltech scientists conducted a study that advances research on future batteries. Their paper, published in Small, sheds light on recent advances in designing multilayered structures of alkali metals, such as lithium, sodium, and potassium, within carbon anode materials.
This technology has the potential to transform the energy storage market, enabling electric vehicles to charge in minutes and providing green energy with stable, safe, and affordable storage systems.
How multilayered structures improve batteries For years, ions were believed to form only single-atom layers in a battery’s carbon materials, such as graphite. In 2018, researchers used a high-precision electron microscope and discovered a new configuration with ultradense, multiatom layers of lithium forming between two sheets of graphene.
