Matter inside neutron stars can have different forms: a dense liquid of nucleons or a dense liquid of quarks.
Recent studies reveal that in neutron stars, quark liquids are fundamentally different from nucleon liquids, as evidenced by the unique color-magnetic field in their vortices. This finding challenges previous beliefs in quantum chromodynamics and offers new insights into the nature of confinement.
The science of neutron star matter.
A team of researchers from the ITACA Institute of the Universitat Politècnica de València (UPV) and the Research Institute of Chemical Technology, a joint center of the Spanish National Research Council (CSIC) and the UPV, has discovered a new method for the manufacture of metal nanocatalysts that is more sustainable and economical.
With great potential in the industrial sector, the method would contribute to the decarbonization of industry. The work has been published in the journal ACS Nano.
This new method is based on the exsolution process activated by microwave radiation. Exsolution is a method of generating metallic nanoparticles on the surface of ceramic materials. “At elevated temperatures and in a reducing atmosphere (usually hydrogen), metal atoms migrate from the structure of the material to its surface, forming metal nanoparticles anchored to the surface. This anchoring significantly increases the strength and stability of these nanoparticles, which positively impacts the efficiency of these catalysts,” explains Beatriz García Baños, a researcher in the Microwave Area of the ITACA Institute at the UPV.
New theoretical analysis places the likelihood of massive neutron stars hiding cores of deconfined quark matter between 80 and 90 percent. The result was reached through massive supercomputer runs utilizing Bayesian statistical inference.
Neutron star cores contain matter at the highest densities reached in our present-day Universe, with as much as two solar masses of matter compressed inside a sphere of 25 km in diameter. These astrophysical objects can indeed be thought of as giant atomic nuclei, with gravity compressing their cores to densities exceeding those of individual protons and neutrons manyfold.
These densities make neutron stars interesting astrophysical objects from the point of view of particle and nuclear physics. A longstanding open problem concerns whether the immense central pressure of neutron stars can compress protons and neutrons into a new phase of matter, known as cold quark matter. In this exotic state of matter, individual protons and neutrons no longer exist.
SN 1,006, a supernova observed over a millennium ago, has been extensively studied using NASA ’s Chandra and IXPE telescopes, revealing critical details about its magnetic field and particle acceleration, contributing to our understanding of cosmic rays.
When the object now called SN 1,006 first appeared on May 1, 1006 A.D., it was far brighter than Venus and visible during the daytime for weeks. Astronomers in China, Japan, Europe, and the Arab world all documented this spectacular sight, which was later understood to have been a supernova. With the advent of the Space Age in the 1960s, scientists were able to launch instruments and detectors above Earth’s atmosphere to observe the Universe in wavelengths that are blocked from the ground, including X-rays. The remains of SN 1,006 was one of the faintest X-ray sources detected by the first generation of X-ray satellites.
Recent observations with nasa’s x-ray telescopes.
Atomic nuclei are made of nucleons (like protons and neutrons), which themselves are made of quarks. When crushed at high densities, nuclei dissolve into a liquid of nucleons and, at even higher densities, the nucleons themselves dissolve into a quark liquid.
In a new study, published in the journal Physical Review B, researchers addressed the question of whether the liquids of nucleons and quarks are fundamentally different.
Their theoretical calculations suggest that these liquids are different. Both types of liquids produce vortices when they rotate, but in quark liquids, the vortices carry a “color-magnetic field,” similar to an ordinary magnetic field. There is no such effect in nucleon liquids. Thus, these vortices sharply distinguish quark liquids from nuclear liquids.
The Compact Muon Solenoid (CMS) ongoing Run 3 experiment has presented its initial findings about the elusive dark photons.
The Large Hadron Collider, located at CERN (European Organization for Nuclear Research) near Geneva, Switzerland, is the world’s most powerful and biggest particle accelerator.
It is made up of a 27-kilometer ring of superconducting magnets and accelerating structures that accelerate protons and other heavy particles to near-light speeds. The LHC is meant to smash these particles, allowing scientists to investigate the fundamental features of matter as well as the forces that govern the universe.
The LHC’s Run 3 experiment began in July of last year.
Researchers at Peking University in China have successfully observed the elusive 02+ state of 8 He, revealing a novel cluster structure with two strongly correlated neutron pairs. This finding provides insights into exotic nuclear structures and their potential implications for understanding neutron stars. The findings are published in Physical Review Letters.
The conventional nuclear model in physics posits a single-particle picture where nucleons, protons, and neutrons move independently within a nucleus, forming a well-defined shell structure. Governed by a mean potential created by nuclear forces, nucleons fill distinct energy levels or shells, leading to increased stability associated with magic numbers.
This model, rooted in quantum mechanics, successfully explains nuclear structure and stability but encounters limitations when addressing exotic nuclei, particularly those that are neutron-rich and unstable.
In 2015, the LIGO/Virgo experiment, a large-scale research effort based at two observatories in the United States, led to the first direct observation of gravitational waves. This important milestone has since prompted physicists worldwide to devise new theoretical descriptions for the dynamics of blackholes, building on the data collected by the LIGO/Virgo collaboration.
Researchers at Uppsala University, University of Oxford, and Université de Mons recently set out to explain the dynamics of Kerr black holes, theoretically predicted black holes that rotate at a constant rate, using theory of massive high-spin particles. Their paper, published in Physical Review Letters, specifically proposes that the dynamics of these rotating black holes is constrained by the principle of gauge symmetry, which suggests that some changes of parameters of a physical system would have no measurable effect.
“We pursued a connection between rotating Kerr black holes and massive higher-spin particles,” Henrik Johansson, co-author of the paper, told Phys.org. “In other words, we modeled the black hole as a spinning fundamental particle, similar to how the electron is treated in quantum electrodynamics.”
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Two protons next to each other in an atomic nucleus are repelling each other electromagnetically with enough force to lift a medium-sized labradoodle off the ground. Release this energy and you have, well, you have a nuclear explosion. Just as well there’s an even stronger force than the electromagnetism holding our nuclei together. But it’s not the strong force, as you might have imagined. At least not directly. Nuclei are held together by a quirk of nature, without which we would have no complex atoms, no chemistry, and certainly no labradoodles.
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