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Category: particle physics – Page 11

Probing hyperon potential to resolve a longstanding puzzle in neutron stars

A research team led by Prof. Yong Gaochan from the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences has proposed a novel experimental method to probe the hyperon potential, offering new insights into resolving the longstanding “hyperon puzzle” in neutron stars. These findings were published in Physics Letters B and Physical Review C.

According to conventional theories, the extreme densities within neutron stars lead to the production of hyperons containing strange quarks (e.g., Λ particles). These hyperons significantly soften the equation of state (EoS) and reduce the maximum mass of neutron stars. However, have discovered neutron stars with masses approaching or even exceeding twice that of the sun, contradicting theoretical predictions.

Hyperon potential refers to the interaction potential between a hyperon and a nucleon. Aiming to resolve the “neutron star hyperon puzzle,” the study of hyperon potential has emerged as a frontier topic in the interdisciplinary field of nuclear and astrophysics. Currently, it is believed that if hyperon potentials exhibit stronger repulsion at high densities, they could counteract the softening effect of the EoS, thereby allowing massive to exist.

Magnetic surface enables precise atomic migration at near absolute zero

Adatoms are single atoms that get adsorbed onto the surface of a solid material and are known to hop randomly from one spot to another. In a recent study published in Nature Communications, a group of scientists from Germany demonstrated that single atoms can be steered in a chosen direction at near absolute zero temperatures (4 Kelvin), provided the surface being used is magnetic in nature—a discovery that can open up new possibilities for precise control of atomic motion, a sought-after ability in the field of nanotechnology, data storage and functional materials.

The researchers placed individual cobalt, rhodium, and iridium atoms on a 1-atom-thick manganese surface to create a magnetically well-defined surface and studied the migration behavior of adatoms using a scanning tunneling microscope (STM) at a temperature of 4 K.

According to established findings from nonmagnetic surfaces, atomic movement is usually governed by surface symmetry. In a hexagonal manganese monolayer like the one used in the study, atoms would be expected to migrate randomly in any of six directions. Yet in a surprising twist, researchers found that when a short, localized voltage pulse from the STM was applied, the atoms consistently moved in just one direction.

Study predicts existence of Type-III multiferroics, which exhibit ferroelectricity-driven magnetism

Multiferroics are materials that exhibit more than one ferroic property, typically ferroelectricity (i.e., a spontaneous electric polarization that can be reversed by electric fields) and ferromagnetism (i.e., the spontaneous magnetic ordering of electron spins). These materials have proved promising for the development of various new technologies, including spintronics, devices that exploit the spin of electrons to process and store information.

So far, physicists and material scientists have uncovered two distinct types of multiferroics, dubbed Type-I and Type-II multiferroics. In Type-I multiferroics, ferroelectricity and arise independently from distinct physical mechanisms, while in Type-II multiferroics, ferroelectricity is driven by magnetic ordering.

Researchers at Nanjing University of Science and Technology recently predicted the existence of a third type of multiferroics, referred to as Type-III multiferroics, in which magnetism is driven by ferroelectricity. Their paper, published in Physical Review Letters, could inspire future efforts aimed at identifying materials with the characteristics they described, which could be highly advantageous for the advancement of spintronics as well as other memory and information processing systems.

Physicists observe a new form of magnetism for the first time

MIT physicists have demonstrated a new form of magnetism that could one day be harnessed to build faster, denser, and less power-hungry “spintronic” memory chips.

The new magnetic state is a mash-up of two main forms of magnetism: the ferromagnetism of everyday fridge magnets and compass needles, and antiferromagnetism, in which materials have magnetic properties at the microscale yet are not macroscopically magnetized.

Now, the MIT team has demonstrated a new form of magnetism, termed “p-wave magnetism.”

Electron Handedness in a Material

A new framework for studying chiral materials puts the emphasis on electron chirality rather than on the asymmetry of the atomic structure.

Chirality is a fundamental feature of nature, manifesting across scales—from elementary particles and molecules to biological organisms and galaxy formation. An object is considered chiral if it cannot be superimposed on its mirror image. In condensed-matter physics, chirality is primarily viewed as a structural asymmetry in the spatial arrangement of atoms within a crystal lattice [1]. A perhaps less familiar fact is that chirality is also a fundamental quantum property of individual electron states [2]. Now, Tatsuya Miki from Saitama University in Japan and colleagues introduce electron chirality as a framework to quantify symmetry breaking in solids, focusing on chiral and related axial materials [3]. The researchers propose a way of measuring electron chirality with photoemission spectroscopy.

‘String breaking’ observed in 2D quantum simulator

An international team led by Innsbruck quantum physicist Peter Zoller, together with the US company QuEra Computing, has directly observed a gauge field theory similar to models from particle physics in a two-dimensional analog quantum simulator for the first time. The study, published in Nature, opens up new possibilities for research into fundamental physical phenomena.

String breaking occurs when the string between two strongly bound particles, such as a quark-antiquark pair, breaks and new particles are created. This concept is central to understanding the that occur in (QCD), the theory that describes the binding of quarks in protons and neutrons.

String breaking is extremely difficult to observe experimentally, as it only occurs in nature under extreme conditions. The recent work by scientists from the Universities of Innsbruck and Harvard, the ÖAW-Institute for Quantum Optics and Quantum Information (IQOQI) and the quantum computer company QuEra shows for the first time how this phenomenon can be reproduced in an analog quantum .

How physicists used antimatter, supercomputers and giant magnets to solve a 20-year-old mystery

Physicists are always searching for new theories to improve our understanding of the universe and resolve big unanswered questions.

But there’s a problem. How do you search for undiscovered forces or particles when you don’t know what they look like?

Take . We see signs of this mysterious cosmic phenomenon throughout the universe, but what could it possibly be made of? Whatever it is, we’re going to need new physics to understand what’s going on.

Scientists steer single atoms on magnetic surfaces for first time

Scientists in Germany have achieved a world first by moving individual atoms from one position to a precisely defined final one using magnetism, unlocking the potential for controlled atomic motion in nanotechnology and data storage.

The research team from the University of Kiel (CAU) and the University of Hamburg used a highly sensitive scanning tunneling microscope (STM) to manipulate atoms on a specially engineered magnetic surface.

Strain can unlock electron-donating orbital in tetravalent carbon atoms

Scheiner and Zierkiewicz, however, have been studying apical carbon atoms in propellane and pyramidane molecules, where the bonding situation is rather different. Along with Mariusz Michalczyk, also at Wrocław University of Science and Technology, they’ve identified an electron-donating orbital – or pseudo lone pair – on these tetrahedral carbons.

While it clearly has a negative charge, Scheiner acknowledges that the nature of this electron-donating orbital could be up for debate. Nonetheless, it appears that this region of negative electrostatic potential can attract the σ-hole of an electrophile to form various non-covalent interactions including hydrogen, halogen, chalcogen, pnictogen and tetrel bonds.