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Category: particle physics

Researchers have found that graphene-enhanced hard drives can store data at ten times the density of existing HDDs.

By leveraging the wonder material graphene, a group at the University of Cambridge is claiming an advance in data storage that resembles more of a leap than a step forward. The new design unlocks higher operating temperatures for hard disk drives (HDDs) and with it, unprecedented data density, which the team says represents a ten-fold increase on current technologies.

In a HDD, data is written onto fast-spinning platters by a moving magnetic head. Special layers called carbon-based overcoats (COCs) protect these platters from mechanical damage and corrosion during operation, though these can only perform within a certain temperature range and also take up a lot of space.

The Cambridge researchers were able to replace the COCs used in commercial HDDs with between one and four layers of graphene, a material that is a single layer of carbon atoms with incredible strength and flexibility, among other highly-valued properties. The thinness of the graphene enabled significant space savings but also outperformed current COCs in preventing mechanical wear, reduced corrosion by 2.5 times and also offered a two-fold reduction in friction.

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To test the Standard Model of particle physics, scientists often collide particles using gigantic underground rings. In a similar fashion, high-pressure physicists compress materials to ever greater pressures to further test the quantum theory of condensed matter and challenge predictions made using the most powerful computers.

Pressures exceeding 1 million atmospheres are capable of dramatically deforming atomic electronic clouds and alter how atoms are packed together. This leads to new chemical bonding and has revealed extraordinary behaviors such as helium rain, the transformation of sodium into a transparent metal, the emergence of superionic water ice and the transformation of hydrogen into a metallic fluid.

With new techniques constantly advancing the frontier of high– physics, terapascal (TPa) pressures that were once inaccessible can now be achieved in the laboratory using static or dynamic compression (1 TPa is equivalent to approximately 10 million atmospheres).

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In the cold, dense medium of a helium-3 superfluid, scientists recently made an unexpected discovery. A foreign object travelling through the medium could exceed a critical speed limit without breaking the fragile superfluid itself.

As this contradicts our understanding of superfluidity, it presented quite a puzzle — but now, by recreating and studying the phenomenon, physicists have figured out how it happens. Particles in the superfluid stick to the object, shielding it from interacting with the bulk superfluid, thus preventing the superfluid’s breakdown.

“Superfluid helium-3 feels like a vacuum to a rod moving through it, although it is a relatively dense liquid. There is no resistance, none at all,” said physicist Samuli Autti of Lancaster University in the UK. “I find this very intriguing.”

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O,.o! Woah

When heavy ions, accelerated to the speed of light, collide with each other in the depths of European or American accelerators, quark-gluon plasma is formed for fractions of a second, or even its “cocktail” seasoned with other particles. According to scientists from the IFJ PAN, experimental data show that there are underestimated actors on the scene: photons. Their collisions lead to the emission of seemingly excess particles, the presence of which could not be explained.

Quark-gluon plasma is undoubtedly the most exotic state of matter thus far known to us. In the LHC at CERN near Geneva, it is formed during central collisions of two lead ions approaching each other from opposite directions, traveling at velocities very close to that of light. This quark-gluon soup is also sometimes seasoned with other particles. Unfortunately, the theoretical description of the course of events involving plasma and a cocktail of other sources fails to describe the data collected in the experiments.

In an article published in Physics Letters B, a group of scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow explained the reason for the observed discrepancies. Data collected during collisions of lead nuclei in the LHC, as well as during collisions of gold nuclei in the RHIC at Brookhaven National Laboratory near New York, begin to agree with the theory when the description of the processes takes into account collisions between photons surrounding both interacting ions.

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Smashing together lead particles at 99.9999991 percent the speed of light, scientists have recreated the first matter that appeared after the Big Bang.

Out of the wreck came a primordial type of matter known as quark-gluon plasma, or QGP. It only lasted a fraction of a second, but for the first time, scientists were able to probe the plasma’s liquid-like characteristics – finding it to have less resistance to flow than any other known substance – and determine how it evolved in the first moments in the early Universe.

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Physicists at the University of Bath in the UK, in collaboration with researchers from the USA, have uncovered a new mechanism for enabling magnetism and superconductivity to co-exist in the same material. Until now, scientists could only guess how this unusual coexistence might be possible. The discovery could lead to applications in green energy technologies and in the development of superconducting devices, such as next-generation computer hardware.

As a rule, superconductivity (the ability of a material to pass an with perfect efficiency) and magnetism (seen at work in fridge magnets) make poor bedfellows because the alignment of the tiny electronic magnetic particles in ferromagnets generally leads to the destruction of the electron pairs responsible for superconductivity. Despite this, the Bath researchers have found that the iron-based superconductor RbEuFe4As4, which is superconducting below-236°C, exhibits both superconductivity and magnetism below-258°C.

Physics postgraduate research student David Collomb, who led the research, explained: There’s a state in some materials where, if you get them really cold—significantly colder than the Antarctic—they become superconducting. But for this superconductivity to be taken to next-level applications, the material needs to show co-existence with . This would allow us to develop devices operating on a magnetic principle, such as magnetic memory and computation using , to also enjoy the benefits of superconductivity.

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A team at Stony Brook University used ORNL’s Summit supercomputer to model x-ray burst flames spreading across the surface of dense neutron stars.

At the heart of some of the smallest and densest stars in the universe lies nuclear matter that might exist in never-before-observed exotic phases. Neutron stars, which form when the cores of massive stars collapse in a luminous supernova explosion, are thought to contain matter at energies greater than what can be achieved in particle accelerator experiments, such as the ones at the Large Hadron Collider and the Relativistic Heavy Ion Collider.

Although scientists cannot recreate these extreme conditions on Earth, they can use neutron stars as ready-made laboratories to better understand exotic matter. Simulating neutron stars, many of which are only 12.5 miles in diameter but boast around 1.4 to 2 times the mass of our sun, can provide insight into the matter that might exist in their interiors and give clues as to how it behaves at such densities.

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Batteries and fuel cells often rely on a process known as ion diffusion to function. In ion diffusion, ionized atoms move through solid materials, similar to the process of water being absorbed by rice when cooked. Just like cooking rice, ion diffusion is incredibly temperature-dependent and requires high temperatures to happen fast.

This temperature dependence can be limiting, as the materials used in some systems like fuel cells need to withstand high temperatures sometimes in excess of 1000 degrees Celsius. In a new study, a team of researchers at MIT and the University of Muenster in Germany showed a new effect, where ion is enhanced while the material remains cold, by only exciting a select number of vibrations known as phonons. This new approach—which the team refers to as “ catalysis”—could lead to an entirely new field of research. Their work was published in Cell Reports Physical Science.

In the study, the research team used a to determine which vibrations actually caused ions to move during ion diffusion. Rather than increasing the temperature of the entire material, they increased the temperature of just those specific vibrations in a process they refer to as targeted phonon excitation.

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What is time? What is humankind’s role in the universe? What is the meaning of life? For much of human history, these questions have been the province of religion and philosophy. What answers can science provide?

In this talk, Sean Carroll will share what physicists know, and don’t yet know, about the nature of time. He’ll argue that while the universe might not have purpose, we can create meaning and purpose through how we approach reality, and how we live our lives.

Sean Carroll is a Research Professor of theoretical physics at the California Institute of Technology, and an External Professor at the Santa Fe Institute. His research has focused on fundamental physics and cosmology, especially issues of dark matter, dark energy, spacetime symmetries, and the origin of the universe.

Recently, Carroll has worked on the foundations of quantum mechanics, the emergence of spacetime, and the evolution of entropy and complexity. Carroll is the author of Something Deeply Hidden, The Big Picture, The Particle at the End of the Universe amongst other books and hosts the Mindscape podcast.

“The Passage of Time and the Meaning of Life” was given on May 4, 02021 as part of Long Now’s Seminar series. The series was started in 02003 to build a compelling body of ideas about long-term thinking from some of the world’s leading thinkers. The Seminars take place in San Francisco and are curated and hosted by Stewart Brand. To follow the talks, you can:

Explore the full series: http://longnow.org/seminars.
More ideas on long-term thinking: http://blog.longnow.org.

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JÜLICH, Germany, May 28, 2021 — Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can result in the loss of sensitive quantum effects. In the renowned journal Science, however, researchers from TU Delft, RWTH Aachen University and Forschungszentrum Jülich now present an experiment in which a quantum system consisting of two coupled atoms behaves surprisingly stable under electron bombardment. The experiment provide an indication that special quantum states might be realised in a quantum computer more easily than previously thought.

The so-called decoherence is one of the greatest enemies of the quantum physicist. Experts understand by this the decay of quantum states. This inevitably occurs when the system interacts with its environment. In the macroscopic world, this exchange is unavoidable, which is why quantum effects rarely occur in daily life. The quantum systems used in research, such as individual atoms, electrons or photons, are better shielded, but are fundamentally similarly sensitive.

“Systems subject to quantum physics, unlike classical objects, are not sharply defined in all their properties. Instead, they can occupy several states at once. This is called superposition,” Markus Ternes explains. “A famous example is Schrödinger’s thought experiment with the cat, which is temporarily dead and alive at the same time. However, the superposition breaks down as soon as the system is disturbed or measured. What is left then is only a single state, which is the measured value,” says the quantum physicist from Forschungszentrum Jülich and RWTH Aachen University.

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