Wednesday, November 20, 2024

Constraining Galaxy-Halo Connection with Machine Learning #sciencefather...

at No comments:

Scientists Smash Atoms to Smithereens, Revealing Hidden Nuclear Shapes







Scientists employ high-energy heavy ion collisions as a powerful tool to uncover intricate details of nuclear structure, offering insights with broad implications across various fields of physics.

Scientists have developed a novel technique using high-energy particle collisions at the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research located at DOE’s Brookhaven National Laboratory. Detailed in a newly published paper in Nature, this method complements lower-energy approaches for studying nuclear structure. It offers deeper insights into the shapes of atomic nuclei, enhancing our understanding of the building blocks of visible matter.

“In this new measurement, we not only quantify the overall shape of the nucleus whether it’s elongated like a football or squashed down like a tangerine but also the subtle triaxiality, the relative differences among its three principle axes that characterize a shape in between the ‘football’ and ‘tangerine,’” said Jiangyong Jia, a professor at Stony Brook University (SBU) who has a joint appointment at Brookhaven Lab and is one of the principal authors on the STAR Collaboration publication.

Deciphering nuclear shapes has relevance to a wide range of physics questions, including which atoms are most likely to split in nuclear fission, how heavy atomic elements form in collisions of neutron stars, and which nuclei could point the way to exotic particle decay discoveries. Leveraging improved knowledge of nuclear shapes will also deepen scientists’ understanding of the initial conditions of a particle soup that mimics the early universe, which is created in RHIC’s energetic particle smashups. The method can be applied to analyzing additional data from RHIC as well as data collected from nuclear collisions at Europe’s Large Hadron Collider (LHC). It will also have relevance to future explorations of nuclei at the Electron-Ion Collider, a nuclear physics facility in the design stage at Brookhaven Lab.

Ultimately, since 99.9% of the visible matter that people and all the stars and planets of the cosmos are made of resides in the nuclei at the center of atoms, understanding these nuclear building blocks is at the heart of understanding who we are.

“The best way to demonstrate the robustness of nuclear physics knowledge gained at RHIC is to show that we can apply the technology and physics insights to other fields,” Jia said. “Now that we’ve demonstrated a robust way to image nuclear structure, there will be many applications.”

From long exposure to freeze-frame snapshots

For decades, scientists used low-energy experiments to infer nuclear shapes  for example, by exciting the nuclei and observing photons, or particles of light, emitted as the nuclei decay back to the ground state. This method probes the overall spatial arrangement of the protons inside the nucleus, but only at a relatively long time scale.

“In low-energy experiments, it’s like taking a long-exposure picture,” said Chun Shen, a theorist at Wayne State University whose calculations were used in the new analysis.

Because the exposure time is long, the low-energy methods do not capture all the subtle variations in the arrangement of protons that can occur inside a nucleus at very fast timescales. And because most of these methods use electromagnetic interactions, they can’t directly “see” the uncharged neutrons in the nucleus.

“You only get an average of the whole system,” said Dean Lee, a low-energy theorist at the Facility for Rare Isotope Beams, a DOE Office of Science user facility at Michigan State University. Though Lee and Shen are not co-authors on the study, they and other theorists have contributed to developing this new nuclear imaging method.

Reconstructing shapes from debris

How exactly does STAR see that complexity if the nuclei get destroyed? By tracking how particles fly out  and how fast  from the most central, head-on nuclear smashups.

As the STAR scientists note in their Nature paper, “In an ironic twist, this effectively realizes [famous physicist] Richard Feynman’s analogy of the seemingly impossible task of ‘figuring out a pocket watch by smashing two together and observing the flying debris.’”

From years of experiments at RHIC, the scientists know that high energy nuclear collisions melt the protons and neutrons of the nuclei to set free their inner building blocks, quarks and gluons. The shape and expansion of each hot blob of this melted nuclear matter, known as a quark-gluon plasma (QGP), is determined by the shape of the colliding nuclei. The shape and size of each QGP blob directly affect pressure gradients generated in that blob of plasma, which in turn influence the collective flow and momentum of particles emitted as the QGP cools.

The STAR scientists reasoned they could “reverse engineer” this relationship to derive information about nuclear structure. They analyzed the flow and momentum of particles emerging from collisions and compared them with models of hydrodynamic expansion for different QGP shapes to arrive at the shapes of the originally colliding nuclei.

Website: International Research Awards on High Energy Physics and Computational Science.

#HighEnergyPhysics#ParticlePhysics#QuantumPhysics#AstroparticlePhysics#ColliderPhysics#HiggsBoson#LHC#QuantumFieldTheory#NeutrinoPhysics#PhysicsResearch#ComputationalScience#DataScience#ScientificComputing#NumericalMethods#HighPerformanceComputing#MachineLearningInScience#BigData#AlgorithmDevelopment#SimulationScience#ParallelComputing

at No comments:

Tuesday, November 19, 2024

Beyond Imagination: 140 Milky Ways Spanned by Record-Breaking Black Hole Jets




Astronomers have identified the largest black hole jet structure known, named Porphyrion, stretching 23 million light-years across, akin to 140 Milky Way galaxies aligned.

This discovery, emerging from a galaxy about 10 times the mass of our Milky Way, suggests that such jets could significantly impact galaxy formation and cosmic magnetic fields.

Discovery of Colossal Black Hole Jets

Astronomers have spotted the biggest pair of black hole jets ever seen, spanning 23 million light-years in total length. That’s equivalent to lining up 140 Milky Way galaxies back to back.

“This pair is not just the size of a solar system, or a Milky Way; we are talking about 140 Milky Way diameters in total,” says Martijn Oei, a Caltech postdoctoral scholar and lead author of a new Nature paper reporting the findings. “The Milky Way would be a little dot in these two giant eruptions.”



Unveiling Porphyrion: A Record-Breaking Jet System

The jet megastructure, nicknamed Porphyrion after a giant in Greek mythology, dates to a time when our universe was 6.3 billion years old, or less than half its present age of 13.8 billion years. These fierce outflows with a total power output equivalent to trillions of suns shoot out from above and below a supermassive black hole at the heart of a remote galaxy.

Prior to Porphyrion’s discovery, the largest confirmed jet system was Alcyoneus, also named after a giant in Greek mythology. Alcyoneus, which was discovered in 2022 by the same team that found Porphyrion, spans the equivalent of around 100 Milky Ways. For comparison, the well-known Centaurus A jets (see image below), the closest major jet system to Earth, spans 10 Milky Ways.



Broader Implications for Cosmic Evolution

The latest finding suggests that these giant jet systems may have had a larger influence on the formation of galaxies in the young universe than previously believed. Porphyrion existed during an early epoch when the wispy filaments that connect and feed galaxies, known as the cosmic web, were closer together than they are now. That means enormous jets like Porphyrion reached across a greater portion of the cosmic web compared to jets in the local universe.

The LOFAR Survey: A Sky Full of Giants

The Porphyrion jet system is the biggest found so far during a sky survey that has revealed a shocking number of the faint megastructures: more than 10,000. This massive population of gargantuan jets was found using Europe’s LOFAR (LOw Frequency ARray) radio telescope.

While hundreds of large jet systems were known before the LOFAR observations, they were thought to be rare and on average smaller in size than the thousands of systems uncovered by the radio telescope.

“Giant jets were known before we started the campaign, but we had no idea that there would turn out to be so many,” says Martin Hardcastle, second author of the study and a professor of astrophysics at the University of Hertfordshire in England. “Usually when we get a new observational capability, such as LOFAR’s combination of wide field of view and very high sensitivity to extended structures, we find something new, but it was still very exciting to see so many of these objects emerging.”

Website: International Research Awards on High Energy Physics and Computational Science.

#HighEnergyPhysics#ParticlePhysics#QuantumPhysics#AstroparticlePhysics#ColliderPhysics#HiggsBoson#LHC#QuantumFieldTheory#NeutrinoPhysics#PhysicsResearch#ComputationalScience#DataScience#ScientificComputing#NumericalMethods#HighPerformanceComputing#MachineLearningInScience#BigData#AlgorithmDevelopment#SimulationScience#ParallelComputing



at No comments:

Monday, November 18, 2024

Discovering the Magic of Light Mass Os Isotopes! #sciencefather #Highene...

at No comments:

Cracks in the Cosmos: The Flawed Physics of Massive Stars and Supernovae




Scientists uncovered evidence that astrophysics models of massive stars and supernovae are inconsistent with observational gamma-ray astronomy.

The discovery came after the international research team used an innovative new experimental method to investigate uncertain nuclear properties of an unstable isotope.

Artemis Spyrou, a physics professor at Michigan State University (MSU) and the Facility for Rare Isotope Beams (FRIB), led an international team to study iron-60, a rare and unstable isotope, using a groundbreaking experimental approach. The research, involving Sean Liddick, a chemistry professor at FRIB and head of its Experimental Nuclear Science Department, along with 11 FRIB graduate students and postdoctoral researchers, was published in Nature Communications on November 7.

Investigating the Origins of Iron-60

Iron-60 captivates astrophysicists because it forms inside massive stars and is dispersed across the galaxy during supernova explosions. To study this elusive isotope, Spyrou’s team conducted experiments at the National Superconducting Cyclotron Laboratory (FRIB’s predecessor). Their method was developed in collaboration with Ann-Cecilie Larsen, a professor of nuclear and energy physics, and Magne Guttormsen, professor emeritus, both from the University of Oslo in Norway.

“The unique thing that we brought into this collaboration was that we combined our expertise in nuclear reactions, isotope beams, and beta decay to learn about a reaction that we can’t measure directly,” Spyrou said. “For this paper, we sought to measure enough of the properties surrounding the reaction we were interested in so that we could constrain it better than before.”





Advancing Astrophysical Models

Iron-60 has a long half-life for an unstable isotope more than 2 million years so it leaves a lasting signature of the supernova from which it originated. Specifically, iron-60 emits gamma rays as it decays that scientists can measure and analyze for clues about the life cycle of stars and the mechanisms of their explosive deaths. Physicists rely on this data to create and improve astrophysical models.

“One of the overarching goals of nuclear science is to achieve a comprehensive, predictive model of a nucleus that will accurately describe the nuclear properties of any atomic system,” said Liddick, “but we just don’t have that yet. We have to experimentally measure these processes first.” Scientists need to produce these rare isotopes, observe them, and then compare their findings with the model’s prediction to check for accuracy.

“To study these nuclei, we can’t just find them naturally on Earth,” said Spyrou. “We have to make them. And that is the specialty of FRIB to get stable isotopes that we can find, accelerate them, fragment them, and then produce these exotic isotopes, which might only live for a few milliseconds, so we can study them.” To that end, Spyrou and her team devised an experiment that served two purposes: First, they aimed to constrain the neutron-capture process that transforms the isotope iron-59 into iron-60; second, they wanted to use the resulting data to investigate long-standing discrepancies between supernova model predictions and the observed traces of these isotopes.

Pioneering the Beta-Oslo Method

While iron-60 has a relatively long half-life, its neighbor iron-59 is less stable and will decay with a half-life of 44 days. This makes the neutron capture on iron-59 especially challenging to measure in the laboratory since it decays away before reasonable measurements can be performed. To overcome this problem, the scientists developed their own indirect methods of constraining this reaction experimentally.

Spyrou and Liddick worked closely with their colleagues at the University of Oslo to develop a new method for studying these highly unstable isotopes. The result, called the beta-Oslo Method, is a variation of the Oslo Method first developed by project co-author Guttormsen at the Oslo Cyclotron Laboratory. Guttormsen’s approach uses a nuclear reaction to populate a nucleus so that researchers can measure its properties. Though it has proven over several decades to have many astrophysics and nuclear structure applications, it was only possible to apply to (near-) stable isotopes. By combining their expertise in detection, beta decay, and reactions, the researchers devised a way to populate a target nucleus using the process of beta decay itself rather than a reaction. This innovative approach produced the isotope they were looking for much more efficiently and provided a path to constraining neutron-capture reactions on short-lived nuclei.

“The beta-Oslo method is still the only technique that can give us some of these constraints on very exotic nuclei that are far from stability,” said Spyrou.

Improving Stellar Models

After constraining these key uncertainties about the nuclear reaction network that produces iron-60, Spyrou’s team concluded that the likelihood of that reaction happening inside a massive star is higher than model predictions by as much as a factor of two. The researchers now believe that theoretical models of supernovae are flawed, and that there are specific stellar properties that are still incorrectly represented. In their paper’s conclusion, the researchers stated, “The solution to the puzzle must come from the stellar modeling by, for example, reducing stellar rotation, assuming smaller explodability mass limits for massive stars, or modifying other stellar parameters.”

This discovery not only has far-reaching implications for the theoretical understanding of massive stars and the conditions inside them, but it also further demonstrated that the beta-Oslo Method will be a valuable tool for scientists moving forward. “This wouldn’t have worked without our project partners at the University of Oslo, who inspired Artemis and me when they presented the Oslo method at a 2014 seminar at MSU,” said Liddick. “We approached them that day with our question about using beta decay, and discussions took off from there. We’ve worked together ever since, and I have no doubt we will continue to collaborate long into the future.”

Website: International Research Awards on High Energy Physics and Computational Science.

#HighEnergyPhysics#ParticlePhysics#QuantumPhysics#AstroparticlePhysics#ColliderPhysics#HiggsBoson#LHC#QuantumFieldTheory#NeutrinoPhysics#PhysicsResearch#ComputationalScience#DataScience#ScientificComputing#NumericalMethods#HighPerformanceComputing#MachineLearningInScience#BigData#AlgorithmDevelopment#SimulationScience#ParallelComputing






at No comments:

Saturday, November 16, 2024

Color-Flavor Locked Quark Stars Explained in 60 Seconds! #sciencefather ...

at No comments:

Scientists Create Photonic Time Crystals That Amplify Light Exponentially




Scientists created photonic time crystals, unique materials that amplify light and could enhance lasers, sensors, and communication technologies.

These crystals exhibit time-based oscillations, allowing for the exponential amplification of light, with potential applications ranging from advanced sensing to communication.

Photonic Time Crystals

Scientists have successfully designed realistic photonic time crystals exotic materials capable of exponentially amplifying light. This breakthrough, an international team of researchers, opens up transformative possibilities in fields like communication, imaging, and sensing, laying the groundwork for faster, more compact lasers, sensors, and other optical technologies.

“This work could lead to the first experimental realization of photonic time crystals, propelling them into practical applications and potentially transforming industries,” says Assistant Professor Viktar Asadchy from Aalto University, Finland. “From high-efficiency light amplifiers and advanced sensors to innovative laser technologies, this research challenges the boundaries of how we can control the light-matter interaction.”

Understanding and Applications of Time Crystals

Photonic time crystals are a unique type of optical material. Unlike traditional crystals, which have repeating structures in space, these crystals remain spatially uniform but oscillate periodically in time. This property creates “momentum band gaps,” unusual states where light effectively pauses inside the crystal while its intensity grows exponentially. To illustrate this extraordinary interaction, imagine light traveling through a medium that alternates between air and water quadrillions of times per second a phenomenon that challenges the conventional understanding of optics and reveals new possibilities.

One potential application for the photonic time crystals is in nanosensing.“Imagine we want to detect the presence of a small particle, such as a virus, pollutant, or biomarker for diseases like cancer. When excited, the particle would emit a tiny amount of light at a specific wavelength. A photonic time crystal can capture this light and automatically amplify it, enabling more efficient detection with existing equipment,” says Asadchy.

Overcoming Technical Challenges

Creating photonic time crystals for visible light has long been challenging due to the need for an extremely rapid yet simultaneously large amplitude variation of material properties. To date, the most advanced experimental demonstration of photonic time crystals developed by members of the same research team  has been limited to much lower frequencies, such as microwaves. In their latest work, the team proposes, through theoretical models and electromagnetic simulations, the first practical approach to achieving “truly optical” photonic time crystals. By using an array of tiny silicon spheres, they predict that the special conditions needed to amplify light that were previously out of reach can finally be achieved in the lab using known optical techniques.

Website: International Research Awards on High Energy Physics and Computational Science.

#HighEnergyPhysics#ParticlePhysics#QuantumPhysics#AstroparticlePhysics#ColliderPhysics#HiggsBoson#LHC#QuantumFieldTheory#NeutrinoPhysics#PhysicsResearch#ComputationalScience#DataScience#ScientificComputing#NumericalMethods#HighPerformanceComputing#MachineLearningInScience#BigData#AlgorithmDevelopment#SimulationScience#ParallelComputing
at No comments:
Subscribe to: Posts (Atom)